Angioedema is an area of swelling (edema) of the lower layer of skin and tissue just under the skin or mucous membranes. The swelling may occur in the face, tongue, larynx, abdomen, or arms and legs. Often it is associated with hives, which are swelling within the upper skin. Onset is typically over minutes to hours. The underlying mechanism typically involves histamine or bradykinin. The version related to histamine is due to an allergic reaction to agents such as insect bites, foods, or medications. The version related to bradykinin may occur due to an inherited problem known as C1 esterase inhibitor deficiency, medications known as angiotensin-converting enzyme inhibitors, or a lymphoproliferative disorder. Treatment to protect the airway may include intubation or cricothyroidotomy. Histamine-related angioedema can be treated with antihistamines, corticosteroids, and epinephrine. In those with bradykinin-related disease a C1 esterase inhibitor, ecallantide, or icatibant may be used. Fresh frozen plasma may be used instead. In the United States the disease affects about 100,000 people a year.

Reference
Wiki: Angioedema

    Haptoglobin (abbreviated as Hp) is the protein that in humans is encoded by the HP gene. In blood plasma, haptoglobin binds with high affinity to free hemoglobin released from erythrocytes, and thereby inhibits its deleterious oxidative activity. Compared to Hp, hemopexin binds to free heme. The haptoglobin-hemoglobin complex will then be removed by the reticuloendothelial system (mostly the spleen). In clinical settings, the haptoglobin assay is used to screen for and monitor intravascular hemolytic anemia. In intravascular hemolysis, free hemoglobin will be released into circulation and hence haptoglobin will bind the hemoglobin. This causes a decline in haptoglobin levels. The protein was discovered as a "plasma substance" in 1938 by French biochemists Max-Fernand Jayle and Michel Polonovski.

Reference
Wiki: Anhaptoglobinemia

    Autoinflammatory diseases (AIDs) are a group of rare disorders caused by dysfunction of the innate immune system. These responses are characterized by periodic or chronic systemic inflammation, usually without the involvement of adaptive immunity. Autoinflammatory diseases are a separate class from autoimmune diseases; however, both are characterized by an immune system malfunction that may cause similar symptoms, such as rash, swelling, or fatigue. However, the main source of the diseases are different. A key difference between the two classes of diseases is that while AIDs triggers a malfunction of the innate immune system, autoimmune diseases trigger a malfunction of the adaptive immune system. The boundaries between autoinflammation (overactivity of the innate immunity), autoimmunity (overactivity of the adaptive immunity), and immunodeficiency (decreased activity of the innate or adaptive immunity) are often fluid. Clinical phenotypes associated with these processes are driven by the cell type most affected by a particular mutation or signal. Excessive activation of neutrophils, monocytes/macrophages, and dendritic cells leads to auto-inflammatory symptoms, while T cell and B cell dysfunction leads to autoimmunity. Failure of innate and/or adaptive immune cells to appropriately activate, recognize, and clear infectious agents causes immunodeficiency and vulnerability to infection.

Reference
Wiki: Autoinflammation, panniculitis, and dermatosis syndrome

    Ichthyosis (also named fish scale disease) is a family of genetic skin disorders characterized by dry, thickened, scaly skin. The more than 20 types of ichthyosis range in severity of symptoms, outward appearance, underlying genetic cause and mode of inheritance (e.g., dominant, recessive, autosomal or X-linked). Ichthyosis comes from the Greek ?¦Ö¦È?? ichthys, literally 'fish', since dry, scaly skin is the defining feature of all forms of ichthyosis. The severity of symptoms can vary enormously, from the mildest, most common, types such as ichthyosis vulgaris, which may be mistaken for normal dry skin, up to life-threatening conditions such as harlequin-type ichthyosis. Ichthyosis vulgaris accounts for more than 95% of cases.

Reference
Wiki: Autosomal recessive congenital ichthyosis

    Epidermolytic ichthyosis (EI), is a severe form of dry scaly skin, that initially presents with redness, blisters, erosions, and peeling in a newborn baby. Hyperkeratosis typically develops several months later. Other symptoms include itch, painful fissures, strong body odor, and absence of sweat. Symptoms vary in severity and extent of skin involvement. The two main types are divided into one involving palms and soles and the other without. EI is caused by a genetic mutation. The condition involves the clumping of keratin filaments. The condition is rare, affecting around 1 in 200,000 to 300,000 babies.

Reference
Wiki: Bullous ichthyosiform erythroderma

    A bone disease characterized by replacement of bone in the jaws with fibrous tissue leding to facial swelling that has_material_basis_in heterozygous mutation in the SH3BP2 gene on chromosome 4p16.3.

Reference
DiseaseOntology: Cherubism

    Chronic mucocutaneous candidiasis is an immune disorder of T cells.[4] It is characterized by chronic infections with Candida that are limited to mucosal surfaces, skin, and nails.[5]:?310? It can also be associated with other types of infections, such as human papilloma virus. An association with chromosome 2 has been identified.

Reference
Wiki: Chronic mucocutaneous candidiasis

     A candidiasis that refers to a heterogeneous group of disorders characterized by recurrent or persistent superficial fungal infections located_in skin, located_in mucous membrane, or located_in nail due to T-cell defects, has-agent Candida species and has_symptom scaling of skin lesions, has_symptom thickening of nails, has_symptom swollen periungal tissue, and has_symptom scarring of the scalp.

Reference
DiseaseOntology: Chronic mucocutaneous candidiasis disease

    The porphyrias are diseases caused by defects in heme synthesis, resulting in the accumulation and increased excretion of porphyrins or porphyrin precursors. They are classified as erythropoietic or hepatic, depending on whether the enzyme deficiency occurs in red blood cells or in the liver.

Reference
OMIM: Congenital erythropoietic porphyria

    A multiple benign circumferential skin creases on limbs characterized by folding of excess skin, which leads to ringed creases, primarily of the limbs, intellectual disability, cleft palate, and dysmorphic features that has_material_basis_in heterozygous mutation in the TUBB gene on chromosome 6p21.33.

Reference
DiseaseOntology: congenital symmetric circumferential skin creases 1

    Melanoma is the most dangerous type of skin cancer; it develops from the melanin-producing cells known as melanocytes.[1] It typically occurs in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma).[1][2] In women, melanomas most commonly occur on the legs; while in men, on the back.[2] Melanoma is frequently referred to as malignant melanoma. However, the medical community stresses that there is no such thing as a 'benign melanoma' and recommends that the term 'malignant melanoma' should be avoided as redundant.[7][8][9]

Reference
Wiki: Cutaneous melanoma

    Melanoma is the most dangerous type of skin cancer; it develops from the melanin-producing cells known as melanocytes. It typically occurs in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma). In women, melanomas most commonly occur on the legs; while in men, on the back. Melanoma is frequently referred to as malignant melanoma. However, the medical community stresses that there is no such thing as a 'benign melanoma' and recommends that the term 'malignant melanoma' should be avoided as redundant. About 25% of melanomas develop from moles. Changes in a mole that can indicate melanoma include increase¡ªespecially rapid increase¡ªin size, irregular edges, change in color, itchiness, or skin breakdown. The primary cause of melanoma is ultraviolet light (UV) exposure in those with low levels of the skin pigment melanin. The UV light may be from the sun or other sources, such as tanning devices. Those with many moles, a history of affected family members, and poor immune function are at greater risk. A number of rare genetic conditions, such as xeroderma pigmentosum, also increase the risk. Diagnosis is by biopsy and analysis of any skin lesion that has signs of being potentially cancerous. Avoiding UV light and using sunscreen in UV-bright sun conditions may prevent melanoma. Treatment typically is removal by surgery of the melanoma and the potentially affected adjacent tissue bordering the melanoma. In those with slightly larger cancers, nearby lymph nodes may be tested for spread (metastasis). Most people are cured if metastasis has not occurred. For those in whom melanoma has spread, immunotherapy, biologic therapy, radiation therapy, or chemotherapy may improve survival. With treatment, the five-year survival rates in the United States are 99% among those with localized disease, 65% when the disease has spread to lymph nodes, and 25% among those with distant spread. The likelihood that melanoma will reoccur or spread depends on its thickness, how fast the cells are dividing, and whether or not the overlying skin has broken down. Melanoma is the most dangerous type of skin cancer. Globally, in 2012, it newly occurred in 232,000 people. In 2015, 3.1 million people had active disease, which resulted in 59,800 deaths. Australia and New Zealand have the highest rates of melanoma in the world. High rates also occur in Northern Europe and North America, while it is less common in Asia, Africa, and Latin America. In the United States, melanoma occurs about 1.6 times more often in men than women. Melanoma has become more common since the 1960s in areas mostly populated by people of European descent.

Reference
Wiki: Cutaneous metastatic melanoma

    Cutaneous squamous-cell carcinoma (cSCC), also known as squamous-cell carcinoma of the skin or squamous-cell skin cancer, is one of the three principal types of skin cancer, alongside basal-cell carcinoma and melanoma.[10] cSCC typically presents as a hard lump with a scaly surface, though it may also present as an ulcer.[1] Onset and development often occurs over several months.[4] Compared to basal cell carcinoma, cSCC is more likely to spread to distant areas.[11] When confined to the epidermis, the outermost layer of the skin, the pre-invasive or in situ form of cSCC is termed Bowen's disease.[12][13]

Reference
Wiki: Cutaneous squamous cell carcinoma

    Cutaneous T-cell lymphoma (CTCL) is a class of non-Hodgkin lymphoma, which is a type of cancer of the immune system. Unlike most non-Hodgkin lymphomas (which are generally B-cell-related), CTCL is caused by a mutation of T cells. The cancerous T cells in the body initially migrate to the skin, causing various lesions to appear. These lesions change shape as the disease progresses, typically beginning as what appears to be a rash which can be very itchy and eventually forming plaques and tumors before spreading to other parts of the body.

Reference
Wiki: Cutaneous T-cell lymphoma

    Cutis laxa or pachydermatocele is a group of rare connective tissue disorders in which the skin becomes inelastic and hangs loosely in folds.

Reference
Wiki: Cutis laxa

    Darier's disease (DD) is a rare, genetic skin disorder. It is an autosomal dominant disorder discovered by French dermatologist Ferdinand-Jean Darier in 1889.

Reference
Wiki: Darier disease

    Buschke¨COllendorff syndrome (BOS) is a rare genetic skin disorder associated with LEMD3, that typically presents with widespread painless papules. It is inherited in an autosomal dominant manner. Conditions that may appear similar include tuberous sclerosis, pseudoxanthoma elasticum, neurofibroma, and lipoma, among others. Its frequency is almost 1 case per every 20,000 people, and it is equally found in both males and females. It is named for Abraham Buschke and Helene Ollendorff Curth, who described the condition in one female in 1928.

Reference
Wiki: Dermatofibrosis lenticularis disseminata

    Dyschromatosis universalis hereditaria is a type of pigmentation disorder of the skin. It is characterized by dark and light spots formed like lace in a generalized distribution. Both autosomal dominant and recessive inheritance have been reported with the disorder. It has been associated with mutations in genes SASH1 and ABCB6. It is a rare genodermatosis.

Reference
Wiki: Dyschromatosis universalis hereditaria

    Epidermolysis bullosa (EB) is a group of rare medical conditions that result in easy blistering of the skin and mucous membranes. Blisters occur with minor trauma or friction and are painful. Its severity can range from mild to fatal. Inherited EB is a rare disease with a prevalence in the United States of 8.2 per million live births. Those with mild cases may not develop symptoms until they start to crawl or walk. Complications may include esophageal narrowing, squamous cell skin cancer, and the need for amputations. EB is due to a mutation in at least one of 16 different genes. Some types are autosomal dominant while others are autosomal recessive. The underlying mechanism is a defect in attachment between or within the layers of the skin. Loss or diminished function of type VII collagen leads to weakness in the structural architecture of the dermal¨Cepidermal junction (DEJ) and mucosal membranes. There are four main types: epidermolysis bullosa simplex (EBS), dystrophic epidermolysis bullosa (DEB), junctional epidermolysis bullosa (JEB), and Kindler syndrome. The diagnosis is suspected based on symptoms and confirmed by skin biopsy or genetic testing. There is no cure for the condition. Management involves wound care, pain control, controlling infections, nutritional support, and prevention and treatment of complications. About half a million people are affected globally. It occurs equally commonly in males and females.

Reference
Wiki: Dystrophic epidermolysis bullosa

    Epidermodysplasia verruciformis (EV) is a skin condition characterised by warty skin lesions. It results from an abnormal susceptibility to HPV infection (HPV) and is associated with a high lifetime risk of squamous cell carcinomas in skin. It generally presents with scaly spots and small bumps particularly on the hands, feet, face and neck; typically beginning in childhood or in a young adult. The bumps tend to be flat, grow in number and then merge to form plaques. On the trunk, it typically appears like pityriasis versicolor; lesions there being slightly scaly and tan, brown, red or looking pale. On the elbows, it may appear like psoriasis. On the forehead, neck and trunk, the lesions may appear like seborrheic keratosis. It is most frequently inherited as an autosomal recessive trait, with some reports of autosomal dominant and X-linked inheritance. Other types include atypical EV which develops due to gene mutations that cause an impaired immune system, and acquired EV which occurs due to acquired immunodeficiency. It is characterized by an inability to protect against HPV infection of skin. HPV types 5 and 8 are detected in around 90% of skin cancers in people with EV. Other types are also associated with EV. In rare cases, the warts may develop into giant horns resulting in treeman syndrome. Prevention of skin cancer requires sun protection. Treatment typically involves surgery; sometimes with the addition of skin grafting. Medications used to treat the lesions include ALA-PDT (photodynamic therapy with aminolevulinic acid), applying 5-FU, imiquimod, and retinoids by mouth. The lesions tend to recur on stopping treatment. The condition is rare. The lesions have been noted to occur at a younger age in warmer climates. EV associated skin cancer develops less frequently in Africans. The condition was first described by Felix Lewandowsky and Wilhelm Lutz in 1922.

Reference
Wiki: Epidermodysplasia verruciformis

    A vesiculobullous skin disease that is characterized by formation of blisters with only minor skin trauma, which can cause widespread wounds, dehydration, electrolyte abnormalities, and severe infection, frequently develops_from mutations in connective tissue elements, including genes encoding keratin, collagen, and laminin.

Reference
DiseaseOntology: Epidermolysis bullosa

    Junctional epidermolysis bullosa 5B with pyloric atresia (JEB5B) is an autosomal recessive blistering disease of skin and mucous membranes. Severity of skin involvement ranges from extensive full thickness skin loss (aplasia cutis congenita) to mild epidermolysis bullosa that improves with age. The plane of skin cleavage is through the lamina lucida of the cutaneous basement membrane zone. Pyloric atresia is usually evident within a few days to weeks of life. Atresia may occur at other gastrointestinal sites including the esophagus and duodenum. JEB5B is usually lethal within the first few weeks of life despite surgical correction of pyloric atresia. Milder, non-lethal forms with less skin blistering have been reported (summary by Has et al., 2020).

Reference
OMIM: Epidermolysis bullosa junctionalis with pyloric atresia

    Epidermolysis bullosa (EB) is a group of rare medical conditions that result in easy blistering of the skin and mucous membranes. Blisters occur with minor trauma or friction and are painful. Its severity can range from mild to fatal. Inherited EB is a rare disease with a prevalence in the United States of 8.2 per million live births. Those with mild cases may not develop symptoms until they start to crawl or walk. Complications may include esophageal narrowing, squamous cell skin cancer, and the need for amputations. EB is due to a mutation in at least one of 16 different genes. Some types are autosomal dominant while others are autosomal recessive. The underlying mechanism is a defect in attachment between or within the layers of the skin. Loss or diminished function of type VII collagen leads to weakness in the structural architecture of the dermal¨Cepidermal junction (DEJ) and mucosal membranes. There are four main types: epidermolysis bullosa simplex (EBS), dystrophic epidermolysis bullosa (DEB), junctional epidermolysis bullosa (JEB), and Kindler syndrome. The diagnosis is suspected based on symptoms and confirmed by skin biopsy or genetic testing. There is no cure for the condition. Management involves wound care, pain control, controlling infections, nutritional support, and prevention and treatment of complications. About half a million people are affected globally. It occurs equally commonly in males and females.

Reference
Wiki: Epidermolysis bullosa simplex

    An ichthyosis that is characterized by generalized erythema, skin blisters and skin fragility, manifested at birth.

Reference
DiseaseOntology: Epidermolytic hyperkeratosis

    Extramammary Paget's disease (EMPD) is a rare and slow-growing malignancy which occurs within the epithelium and accounts for 6.5% of all Paget's disease. The clinical presentation of this disease is similar to the characteristics of mammary Paget's disease (MPD). However, unlike MPD, which occurs in large lactiferous ducts and then extends into the epidermis, EMPD originates in glandular regions rich in apocrine secretions outside the mammary glands. EMPD incidence is increasing by 3.2% every year, affecting hormonally-targeted tissues such as the vulva and scrotum. In women, 81.3% of EMPD cases are related to the vulva, while for men, 43.2% of the manifestations present at the scrotum. The disease can be classified as being either primary or secondary depending on the presence or absence of associated malignancies. EMPD presents with typical symptoms such as scaly, erythematous, eczematous lesions accompanied by itchiness. In addition to this, 10% of patients are often asymptomatic. As a consequence, EMPD has high rates of misdiagnoses and delayed diagnoses. There are a variety of treatment options available, but most are unsuccessful. If caught early and treated, prognosis is generally good.

Reference
Wiki: Extramammary Paget disease

    Gerodermia osteodysplastica (GO) is a rare autosomal recessive connective tissue disorder included in the spectrum of cutis laxa syndromes. Usage of the name "Walt Disney dwarfism" is attributed to the first known case of the disorder, documented in a 1950 journal report, in which the authors described five affected members from a Swiss family as having the physical appearance of dwarves from a Walt Disney film. The terms "geroderma" or "gerodermia" can be used interchangeably with "osteodysplastica" or "osteodysplasticum", with the term "hereditaria" sometimes appearing at the end.

Reference
Wiki: Geroderma osteodysplastica

    Iron overload (also haemochromatosis (British English) or hemochromatosis (American English)) is the abnormal and increased accumulation of total iron in the body causing organ damage. Oxidative stress is the primary mediator of organ damage, as abnormally elevated intracellular iron levels increase free radical formation (via the Fenton reaction). Iron overload is often primary (i.e., hereditary haemochromatosis) but may also be secondary to repeated blood transfusions (i.e., transfusional iron overload). Iron deposition most commonly occurs in the liver, pancreas, skin, heart, and joints. People with iron overload, therefore, classically present with the triad of liver cirrhosis, secondary diabetes mellitus, and bronze skin. However, due to the earlier detection nowadays, symptoms are often limited to general chronic malaise, arthralgia, and hepatomegaly.

Reference
Wiki: Hemochromatosis

    Many skin conditions affect the human integumentary system¡ªthe organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against the external environment. The skin weighs an average of four kilograms, covers an area of two square metres, and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue. The two main types of human skin are: glabrous skin, the hairless skin on the palms and soles (also referred to as the "palmoplantar" surfaces), and hair-bearing skin. Within the latter type, the hairs occur in structures called pilosebaceous units, each with hair follicle, sebaceous gland, and associated arrector pili muscle. In the embryo, the epidermis, hair, and glands form from the ectoderm, which is chemically influenced by the underlying mesoderm that forms the dermis and subcutaneous tissues. The epidermis is the most superficial layer of skin, a squamous epithelium with several strata: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Nourishment is provided to these layers by diffusion from the dermis since the epidermis is without direct blood supply. The epidermis contains four cell types: keratinocytes, melanocytes, Langerhans cells, and Merkel cells. Of these, keratinocytes are the major component, constituting roughly 95 percent of the epidermis. This stratified squamous epithelium is maintained by cell division within the stratum basale, in which differentiating cells slowly displace outwards through the stratum spinosum to the stratum corneum, where cells are continually shed from the surface. In normal skin, the rate of production equals the rate of loss; about two weeks are needed for a cell to migrate from the basal cell layer to the top of the granular cell layer, and an additional two weeks to cross the stratum corneum. The dermis is the layer of skin between the epidermis and subcutaneous tissue, and comprises two sections, the papillary dermis and the reticular dermis. The superficial papillary dermis interdigitates with the overlying rete ridges of the epidermis, between which the two layers interact through the basement membrane zone. Structural components of the dermis are collagen, elastic fibers, and ground substance. Within these components are the pilosebaceous units, arrector pili muscles, and the eccrine and apocrine glands. The dermis contains two vascular networks that run parallel to the skin surface¡ªone superficial and one deep plexus¡ªwhich are connected by vertical communicating vessels. The function of blood vessels within the dermis is fourfold: to supply nutrition, to regulate temperature, to modulate inflammation, and to participate in wound healing. The subcutaneous tissue is a layer of fat between the dermis and underlying fascia. This tissue may be further divided into two components, the actual fatty layer, or panniculus adiposus, and a deeper vestigial layer of muscle, the panniculus carnosus. The main cellular component of this tissue is the adipocyte, or fat cell. The structure of this tissue is composed of septal (i.e. linear strands) and lobular compartments, which differ in microscopic appearance. Functionally, the subcutaneous fat insulates the body, absorbs trauma, and serves as a reserve energy source. Conditions of the human integumentary system constitute a broad spectrum of diseases, also known as dermatoses, as well as many nonpathologic states (like, in certain circumstances, melanonychia and racquet nails). While only a small number of skin diseases account for most visits to the physician, thousands of skin conditions have been described. Classification of these conditions often presents many nosological challenges, since underlying etiologies and pathogenetics are often not known. Therefore, most current textbooks present a classification based on location (for example, conditions of the mucous membrane), morphology (chronic blistering conditions), etiology (skin conditions resulting from physical factors), and so on. Clinically, the diagnosis of any particular skin condition is made by gathering pertinent information regarding the presenting skin lesion(s), including the location (such as arms, head, legs), symptoms (pruritus, pain), duration (acute or chronic), arrangement (solitary, generalized, annular, linear), morphology (macules, papules, vesicles), and color (red, blue, brown, black, white, yellow). Diagnosis of many conditions often also requires a skin biopsy which yields histologic information that can be correlated with the clinical presentation and any laboratory data.

Reference
Wiki: Hereditary cutaneous melanoma

    Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scarring is not usually present. Hair loss in some people causes psychological distress. Common types include male- or female-pattern hair loss, alopecia areata, and a thinning of hair known as telogen effluvium. The cause of male-pattern hair loss is a combination of genetics and male hormones; the cause of female pattern hair loss is unclear; the cause of alopecia areata is autoimmune; and the cause of telogen effluvium is typically a physically or psychologically stressful event. Telogen effluvium is very common following pregnancy. Less common causes of hair loss without inflammation or scarring include the pulling out of hair, certain medications including chemotherapy, HIV/AIDS, hypothyroidism, and malnutrition including iron deficiency. Causes of hair loss that occurs with scarring or inflammation include fungal infection, lupus erythematosus, radiation therapy, and sarcoidosis. Diagnosis of hair loss is partly based on the areas affected. Treatment of pattern hair loss may simply involve accepting the condition, which can also include shaving one's head. Interventions that can be tried include the medications minoxidil (or finasteride) and hair transplant surgery. Alopecia areata may be treated by steroid injections in the affected area, but these need to be frequently repeated to be effective. Hair loss is a common problem. Pattern hair loss by age 50 affects about half of men and a quarter of women. About 2% of people develop alopecia areata at some point in time.

Reference
Wiki: Hypotrichosis

    A skin disease characterized by drying and scaling of skin with the accumulation of thick scales and cracks that may be painful or bleed.

Reference
DiseaseOntology: ichthyosis

    An ichthyosis that is characterized by generalized erythema, skin blisters and skin fragility, manifested at birth.

Reference
DiseaseOntology: Keratinocytic non-epidermolytic nevus

    Darier's disease (DAR) is a rare, inherited skin disorder that presents with multiple greasy, crusting, thick brown bumps that merge into patches. It is an autosomal dominant disorder discovered by French dermatologist Ferdinand-Jean Darier. Mild forms of the disease are the most common, consisting solely of skin rashes that flare up under certain conditions such as high humidity, high stress, or tight-fitting clothes. Short stature, when combined with poorly-formed fingernails that contain vertical striations, is diagnostic even for mild forms of DAR. Symptoms will usually appear in late childhood or early adulthood between the ages of 15 and 30 years and will vary over the lifespan. More severe cases are characterized by dark crusty patches on the skin that are mildly greasy and that emit a strong odor. These patches, also known as keratotic papules, keratosis follicularis, or dyskeratosis follicularis, most often appear on the scalp, forehead, upper arms, chest, back, knees, elbows, and behind the ear.

Reference
Wiki: Keratosis follicularis

    Noonan syndrome with multiple lentigines (NSML) which is part of a group called Ras/MAPK pathway syndromes, is a rare autosomal dominant, multisystem disease caused by a mutation in the protein tyrosine phosphatase, non-receptor type 11 gene (PTPN11). The disease is a complex of features, mostly involving the skin, skeletal and cardiovascular systems, which may or may not be present in all patients. The nature of how the mutation causes each of the condition's symptoms is not well known; however, research is ongoing. It is a RASopathy. Noonan syndrome with multiple lentigines is caused by a different missense mutation of the same gene. Noonan syndrome is fairly common (1:1,000 to 1:2,500 live births), and neurofibromatosis 1 (which was once thought to be related to NSML) is also common (1:3500); however, no epidemiological data exists for NSML.

Reference
Wiki: LEOPARD syndrome

    A palmoplantar keratosis characterized by autosomal recessive inheritance of symmetric palmoplantar hyperkeratosis that progressively extends to the dorsal surfaces of hands and feet and ichthyotic changes elsewhere that has_material_basis_in homozygous mutation in the SLURP1 gene on chromosome 8q24.

Reference
DiseaseOntology: Mal de Meleda

    Meningioma, also known as meningeal tumor, is typically a slow-growing tumor that forms from the meninges, the membranous layers surrounding the brain and spinal cord. Symptoms depend on the location and occur as a result of the tumor pressing on nearby tissue. Many cases never produce symptoms. Occasionally seizures, dementia, trouble talking, vision problems, one sided weakness, or loss of bladder control may occur. Risk factors include exposure to ionizing radiation such as during radiation therapy, a family history of the condition, and neurofibromatosis type 2. They appear to be able to form from a number of different types of cells including arachnoid cells. Diagnosis is typically by medical imaging. If there are no symptoms, periodic observation may be all that is required. Most cases that result in symptoms can be cured by surgery. Following complete removal fewer than 20% recur. If surgery is not possible or all the tumor cannot be removed, radiosurgery may be helpful. Chemotherapy has not been found to be useful. A small percentage grow rapidly and are associated with worse outcomes. About one per thousand people in the United States are currently affected. Onset is usually in adults. In this group they represent about 30% of brain tumors. Women are affected about twice as often as men. Meningiomas were reported as early as 1614 by Felix Plater.

Reference
Wiki: Malignant meningiomas

    Melanoma is the most dangerous type of skin cancer; it develops from the melanin-producing cells known as melanocytes. It typically occurs in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma). In women, melanomas most commonly occur on the legs; while in men, on the back. Melanoma is frequently referred to as malignant melanoma. However, the medical community stresses that there is no such thing as a 'benign melanoma' and recommends that the term 'malignant melanoma' should be avoided as redundant. About 25% of melanomas develop from moles. Changes in a mole that can indicate melanoma include increase¡ªespecially rapid increase¡ªin size, irregular edges, change in color, itchiness, or skin breakdown. The primary cause of melanoma is ultraviolet light (UV) exposure in those with low levels of the skin pigment melanin. The UV light may be from the sun or other sources, such as tanning devices. Those with many moles, a history of affected family members, and poor immune function are at greater risk. A number of rare genetic conditions, such as xeroderma pigmentosum, also increase the risk. Diagnosis is by biopsy and analysis of any skin lesion that has signs of being potentially cancerous. Avoiding UV light and using sunscreen in UV-bright sun conditions may prevent melanoma. Treatment typically is removal by surgery of the melanoma and the potentially affected adjacent tissue bordering the melanoma. In those with slightly larger cancers, nearby lymph nodes may be tested for spread (metastasis). Most people are cured if metastasis has not occurred. For those in whom melanoma has spread, immunotherapy, biologic therapy, radiation therapy, or chemotherapy may improve survival. With treatment, the five-year survival rates in the United States are 99% among those with localized disease, 65% when the disease has spread to lymph nodes, and 25% among those with distant spread. The likelihood that melanoma will reoccur or spread depends on its thickness, how fast the cells are dividing, and whether or not the overlying skin has broken down. Melanoma is the most dangerous type of skin cancer. Globally, in 2012, it newly occurred in 232,000 people. In 2015, 3.1 million people had active disease, which resulted in 59,800 deaths. Australia and New Zealand have the highest rates of melanoma in the world. High rates also occur in Northern Europe and North America, while it is less common in Asia, Africa, and Latin America. In the United States, melanoma occurs about 1.6 times more often in men than women. Melanoma has become more common since the 1960s in areas mostly populated by people of European descent.

Reference
Wiki: Melanoma

    Melanoma is the most dangerous type of skin cancer; it develops from the melanin-producing cells known as melanocytes. It typically occurs in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma). In women, melanomas most commonly occur on the legs; while in men, on the back. Melanoma is frequently referred to as malignant melanoma. However, the medical community stresses that there is no such thing as a 'benign melanoma' and recommends that the term 'malignant melanoma' should be avoided as redundant. About 25% of melanomas develop from moles. Changes in a mole that can indicate melanoma include increase¡ªespecially rapid increase¡ªin size, irregular edges, change in color, itchiness, or skin breakdown. The primary cause of melanoma is ultraviolet light (UV) exposure in those with low levels of the skin pigment melanin. The UV light may be from the sun or other sources, such as tanning devices. Those with many moles, a history of affected family members, and poor immune function are at greater risk. A number of rare genetic conditions, such as xeroderma pigmentosum, also increase the risk. Diagnosis is by biopsy and analysis of any skin lesion that has signs of being potentially cancerous. Avoiding UV light and using sunscreen in UV-bright sun conditions may prevent melanoma. Treatment typically is removal by surgery of the melanoma and the potentially affected adjacent tissue bordering the melanoma. In those with slightly larger cancers, nearby lymph nodes may be tested for spread (metastasis). Most people are cured if metastasis has not occurred. For those in whom melanoma has spread, immunotherapy, biologic therapy, radiation therapy, or chemotherapy may improve survival. With treatment, the five-year survival rates in the United States are 99% among those with localized disease, 65% when the disease has spread to lymph nodes, and 25% among those with distant spread. The likelihood that melanoma will reoccur or spread depends on its thickness, how fast the cells are dividing, and whether or not the overlying skin has broken down. Melanoma is the most dangerous type of skin cancer. Globally, in 2012, it newly occurred in 232,000 people. In 2015, 3.1 million people had active disease, which resulted in 59,800 deaths. Australia and New Zealand have the highest rates of melanoma in the world. High rates also occur in Northern Europe and North America, while it is less common in Asia, Africa, and Latin America. In the United States, melanoma occurs about 1.6 times more often in men than women. Melanoma has become more common since the 1960s in areas mostly populated by people of European descent.

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Wiki: Metastatic melanoma

    A vein disease that is characterized by multiple bluish cutaneous or mucosal venous lesions that has_material_basis_in heterozygous mutation in the TEK gene on chromosome 9p21.

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DiseaseOntology: Multiple cutaneous and mucosal venous malformations

    Pachyonychia congenita (often abbreviated as "PC") is a rare group of autosomal dominant skin disorders that are caused by a mutation in one of five different keratin genes. Pachyonychia congenita is often associated with thickened toenails, plantar keratoderma, and plantar pain.

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Wiki: Pachyonychia congenita

    A syndrome characterized by palmoplantar keratoderma and esophageal cancer that has_material_basis_in heterozygous mutation in the RHBDF2 gene on chromosome 17q25.1.

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DiseaseOntology: Palmoplantar keratoderma-esophageal carcinoma syndrome

    Pityriasis rubra pilaris refers to a group of chronic disorders characterized by reddish orange, scaling plaques and keratotic follicular papules.:?442? Symptoms may include reddish-orange patches (Latin: rubra) on the skin, severe flaking (Latin: pityriasis), uncomfortable itching, thickening of the skin on the feet and hands, and thickened bumps around hair follicles (Latin: pilus for hair). For some, early symptoms may also include generalized swelling of the legs, feet and other parts of the body. PRP has a varied clinical progression and a varied rate of improvement. There is currently no known cause or cure for PRP. It was first described by Marie-Guillaume-Alphonse Devergie in 1856, and the condition is also known as Devergie's disease.

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Wiki: Pityriasis rubra pilaris

    Porokeratosis is a rare skin disorder characterized by one or more annular plaques with a surrounding raised horny border that spreads centrifugally. Variants of porokeratosis have been described that differ in morphologic shapes, distribution, and clinical course (Schamroth et al., 1997). However, as noted by Sybert (2010), several families with expression of more than one variant of porokeratosis among members, and several individuals expressing more than one variant, have been reported, suggesting that the distinctions among these variants may be artificial.

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OMIM: Porokeratosis

    A skin disease that is characterized by patches of thick red skin and silvery scales.

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DiseaseOntology: Psoriasis

    Skin cancers are cancers that arise from the skin. They are due to the development of abnormal cells that have the ability to invade or spread to other parts of the body. Skin cancer is the most commonly diagnosed form of cancer in humans. There are three main types of skin cancers: basal-cell skin cancer (BCC), squamous-cell skin cancer (SCC) and melanoma. The first two, along with a number of less common skin cancers, are known as nonmelanoma skin cancer (NMSC). Basal-cell cancer grows slowly and can damage the tissue around it but is unlikely to spread to distant areas or result in death. It often appears as a painless raised area of skin that may be shiny with small blood vessels running over it or may present as a raised area with an ulcer. Squamous-cell skin cancer is more likely to spread. It usually presents as a hard lump with a scaly top but may also form an ulcer. Melanomas are the most aggressive. Signs include a mole that has changed in size, shape, color, has irregular edges, has more than one color, is itchy or bleeds. More than 90% of cases are caused by exposure to ultraviolet radiation from the Sun. This exposure increases the risk of all three main types of skin cancer. Exposure has increased, partly due to a thinner ozone layer. Tanning beds are another common source of ultraviolet radiation. For melanomas and basal-cell cancers, exposure during childhood is particularly harmful. For squamous-cell skin cancers, total exposure, irrespective of when it occurs, is more important. Between 20% and 30% of melanomas develop from moles. People with lighter skin are at higher risk as are those with poor immune function such as from medications or HIV/AIDS. Diagnosis is by biopsy. Decreasing exposure to ultraviolet radiation and the use of sunscreen appear to be effective methods of preventing melanoma and squamous-cell skin cancer. It is not clear if sunscreen affects the risk of basal-cell cancer. Nonmelanoma skin cancer is usually curable. Treatment is generally by surgical removal but may, less commonly, involve radiation therapy or topical medications such as fluorouracil. Treatment of melanoma may involve some combination of surgery, chemotherapy, radiation therapy and targeted therapy. In those people whose disease has spread to other areas of the body, palliative care may be used to improve quality of life. Melanoma has one of the higher survival rates among cancers, with over 86% of people in the UK and more than 90% in the United States surviving more than 5 years. Skin cancer is the most common form of cancer, globally accounting for at least 40% of cancer cases. The most common type is nonmelanoma skin cancer, which occurs in at least 2¨C3 million people per year. This is a rough estimate, however, as good statistics are not kept. Of nonmelanoma skin cancers, about 80% are basal-cell cancers and 20% squamous-cell skin cancers. Basal-cell and squamous-cell skin cancers rarely result in death. In the United States, they were the cause of less than 0.1% of all cancer deaths. Globally in 2012, melanoma occurred in 232,000 people and resulted in 55,000 deaths. White people in Australia, New Zealand and South Africa have the highest rates of melanoma in the world. The three main types of skin cancer have become more common in the last 20 to 40 years, especially regions where the population is predominantly White.

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Wiki: Skin cancer

    Acral lentiginous melanoma is a type of skin cancer.[6] It typically begins as a uniform brownish mark before becoming darker and wider with a blurred irregular edge, most frequently seen in the foot of a person with darker skin.[6] It may become bumpy and ulcerate.[6] Just under the nail it typically appears as dark longitudinal streaks, and it may spread.[7]

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Wiki: Skin cutaneous melanoma

    The human skin is the outer covering of the body and is the largest organ of the integumentary system. The skin has up to seven layers of ectodermal tissue guarding muscles, bones, ligaments and internal organs. Human skin is similar to most of the other mammals' skin, and it is very similar to pig skin. Though nearly all human skin is covered with hair follicles, it can appear hairless. There are two general types of skin: hairy and glabrous skin (hairless). The adjective cutaneous literally means "of the skin" (from Latin cutis, skin). Skin plays an important immunity role in protecting the body against pathogens and excessive water loss. Its other functions are insulation, temperature regulation, sensation, synthesis of vitamin D, and the protection of vitamin B folates. Severely damaged skin will try to heal by forming scar tissue. This is often discoloured and depigmented. In humans, skin pigmentation (affected by melanin) varies among populations, and skin type can range from dry to non-dry and from oily to non-oily. Such skin variety provides a rich and diverse habitat for the approximately one thousand species of bacteria from nineteen phyla which have been found on human skin.

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Wiki: Skin thickness

    A neoplasm is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists in growing abnormally, even if the original trigger is removed.[3][4][5] This abnormal growth usually forms a mass, which may be called a tumour or tumor.[6]

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Wiki: Skin tumor

    A sebaceous gland disease characterized by the presence of multiple benign sebaceous cysts that has_material_basis_in heterozygous mutation in the KRT17 gene on chromosome 17q21.2.

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DiseaseOntology: Steatocystoma multiplex

    Steatosis, also called fatty change, is abnormal retention of fat (lipids) within a cell or organ.[1] Steatosis most often affects the liver ¨C the primary organ of lipid metabolism ¨C where the condition is commonly referred to as fatty liver disease. Steatosis can also occur in other organs, including the kidneys, heart, and muscle.[2] When the term is not further specified (as, for example, in 'cardiac steatosis'), it is assumed to refer to the liver.[3]

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Wiki: Steatosis

    Congenital symmetric circumferential skin creases (CSCSC) is characterized by the folding of excess skin, which leads to ringed creases, primarily of the limbs. Affected individuals also exhibit intellectual disability, cleft palate, and dysmorphic features (summary by Isrie et al., 2015).

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OMIM: Symmetric circumferential skin creases

    Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun. Common symptoms in humans and other animals include red or reddish skin that is hot to the touch or painful, general fatigue, and mild dizziness. Other symptoms include blistering, peeling skin, swelling, itching, and nausea. Excessive UV radiation is the leading cause of (primarily) non-malignant skin tumors,[1][2] which in extreme cases can be life-threatening. Sunburn is an inflammatory response in the tissue triggered by direct DNA damage by UV radiation. When the cells' DNA is overly damaged by UV radiation, type I cell-death is triggered and the tissue is replaced.[3]

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Wiki: UV-induced skin damage

    A hospital is a healthcare institution providing patient treatment with specialized health science and auxiliary healthcare staff and medical equipment. The best-known type of hospital is the general hospital, which typically has an emergency department to treat urgent health problems ranging from fire and accident victims to a sudden illness. A district hospital typically is the major health care facility in its region, with many beds for intensive care and additional beds for patients who need long-term care. Specialized hospitals include trauma centers, rehabilitation hospitals, children's hospitals, geriatric hospitals, and hospitals for specific medical needs, such as psychiatric hospitals for psychiatric treatment and other disease-specific categories. Specialized hospitals can help reduce health care costs compared to general hospitals. Hospitals are classified as general, specialty, or government depending on the sources of income received. A teaching hospital combines assistance to people with teaching to health science students and auxiliary healthcare students. A health science facility smaller than a hospital is generally called a clinic. Hospitals have a range of departments (e.g. surgery and urgent care) and specialist units such as cardiology. Some hospitals have outpatient departments and some have chronic treatment units. Common support units include a pharmacy, pathology, and radiology. Hospitals are typically funded by public funding, health organizations (for-profit or nonprofit), health insurance companies, or charities, including direct charitable donations. Historically, hospitals were often founded and funded by religious orders, or by charitable individuals and leaders. Hospitals are currently staffed by professional physicians, surgeons, nurses, and allied health practitioners. In the past, however, this work was usually performed by the members of founding religious orders or by volunteers. However, there are various Catholic religious orders, such as the Alexians and the Bon Secours Sisters that still focus on hospital ministry in the late 1990s, as well as several other Christian denominations, including the Methodists and Lutherans, which run hospitals. In accordance with the original meaning of the word, hospitals were original "places of hospitality", and this meaning is still preserved in the names of some institutions such as the Royal Hospital Chelsea, established in 1681 as a retirement and nursing home for veteran soldiers.

Reference
Wiki: Warts

    Xeroderma pigmentosum (XP) is a genetic disorder in which there is a decreased ability to repair DNA damage such as that caused by ultraviolet (UV) light. Symptoms may include a severe sunburn after only a few minutes in the sun, freckling in sun-exposed areas, dry skin and changes in skin pigmentation. Nervous system problems, such as hearing loss, poor coordination, loss of intellectual function and seizures, may also occur. Complications include a high risk of skin cancer, with about half having skin cancer by age 10 without preventative efforts, and cataracts. There may be a higher risk of other cancers such as brain cancers. XP is autosomal recessive, with mutations in at least nine specific genes able to result in the condition. Normally, the damage to DNA which occurs in skin cells from exposure to UV light is repaired by nucleotide excision repair. In people with xeroderma pigmentosum, this damage is not repaired. As more abnormalities form in DNA, cells malfunction and eventually become cancerous or die. Diagnosis is typically suspected based on symptoms and confirmed by genetic testing. There is no cure for XP. Treatment involves completely avoiding the sun. This includes protective clothing, sunscreen and dark sunglasses when out in the sun. Retinoid creams may help decrease the risk of skin cancer. Vitamin D supplementation is generally required. If skin cancer occurs, it is treated in the usual way. The life expectancy of those with the condition is about 30 years less than normal. The disease affects about 1 in 100,000 worldwide. By region, it affects about 1 in 370 in India, 1 in 20,000 in Japan, 1 in 250,000 people in the United States and 1 in 430,000 in Europe. It occurs equally commonly in males and females. Xeroderma pigmentosum was first described in the 1870s by Moritz Kaposi. In 1882, Kaposi coined the term xeroderma pigmentosum for the condition, referring to its characteristic dry, pigmented skin. Individuals with the disease have been referred to as "children of the night" or "moon children".

Reference
Wiki: Xeroderma pigmentosum