Skin DiseasesSkin: The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.Lumpy skin disease virus: A species of CAPRIPOXVIRUS causing a cattle disease occurring in Africa.Psoriasis: A common genetically determined, chronic, inflammatory skin disease characterized by rounded erythematous, dry, scaling patches. The lesions have a predilection for nails, scalp, genitalia, extensor surfaces, and the lumbosacral region. Accelerated epidermopoiesis is considered to be the fundamental pathologic feature in psoriasis.Skin Diseases, Vesiculobullous: Skin diseases characterized by local or general distributions of blisters. They are classified according to the site and mode of blister formation. Lesions can appear spontaneously or be precipitated by infection, trauma, or sunlight. Etiologies include immunologic and genetic factors. (From Scientific American Medicine, 1990)Lumpy Skin Disease: A poxvirus infection of cattle characterized by the appearance of nodules on all parts of the skin.Dermatitis: Any inflammation of the skin.Skin Diseases, Parasitic: Skin diseases caused by ARTHROPODS; HELMINTHS; or other parasites.Skin Neoplasms: Tumors or cancer of the SKIN.Skin Diseases, Viral: Skin diseases caused by viruses.Skin Aging: The process of aging due to changes in the structure and elasticity of the skin over time. It may be a part of physiological aging or it may be due to the effects of ultraviolet radiation, usually through exposure to sunlight.Dermatitis, Atopic: A chronic inflammatory genetically determined disease of the skin marked by increased ability to form reagin (IgE), with increased susceptibility to allergic rhinitis and asthma, and hereditary disposition to a lowered threshold for pruritus. It is manifested by lichenification, excoriation, and crusting, mainly on the flexural surfaces of the elbow and knee. In infants it is known as infantile eczema.Dermatology: A medical specialty concerned with the skin, its structure, functions, diseases, and treatment.Dermatitis, Occupational: A recurrent contact dermatitis caused by substances found in the work place.Skin Diseases, Genetic: Diseases of the skin with a genetic component, usually the result of various inborn errors of metabolism.Skin Physiological Phenomena: The functions of the skin in the human and animal body. It includes the pigmentation of the skin.Epidermis: The external, nonvascular layer of the skin. It is made up, from within outward, of five layers of EPITHELIUM: (1) basal layer (stratum basale epidermidis); (2) spinous layer (stratum spinosum epidermidis); (3) granular layer (stratum granulosum epidermidis); (4) clear layer (stratum lucidum epidermidis); and (5) horny layer (stratum corneum epidermidis).Acne Vulgaris: A chronic disorder of the pilosebaceous apparatus associated with an increase in sebum secretion. It is characterized by open comedones (blackheads), closed comedones (whiteheads), and pustular nodules. The cause is unknown, but heredity and age are predisposing factors.Skin Diseases, Infectious: Skin diseases caused by bacteria, fungi, parasites, or viruses.Keratinocytes: Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell.Prurigo: A name applied to several itchy skin eruptions of unknown cause. The characteristic course is the formation of a dome-shaped papule with a small transient vesicle on top, followed by crusting over or lichenification. (From Dorland, 27th ed)Pemphigus: Group of chronic blistering diseases characterized histologically by ACANTHOLYSIS and blister formation within the EPIDERMIS.Skin Tests: Epicutaneous or intradermal application of a sensitizer for demonstration of either delayed or immediate hypersensitivity. Used in diagnosis of hypersensitivity or as a test for cellular immunity.Eczema: A pruritic papulovesicular dermatitis occurring as a reaction to many endogenous and exogenous agents (Dorland, 27th ed).Skin Absorption: Uptake of substances through the SKIN.Dermatitis, Seborrheic: A chronic inflammatory disease of the skin with unknown etiology. It is characterized by moderate ERYTHEMA, dry, moist, or greasy (SEBACEOUS GLAND) scaling and yellow crusted patches on various areas, especially the scalp, that exfoliate as dandruff. Seborrheic dermatitis is common in children and adolescents with HIV INFECTIONS.Pruritus: An intense itching sensation that produces the urge to rub or scratch the skin to obtain relief.Skin UlcerSkin Diseases, Bacterial: Skin diseases caused by bacteria.Rosacea: A cutaneous disorder primarily of convexities of the central part of the FACE, such as FOREHEAD; CHEEK; NOSE; and CHIN. It is characterized by FLUSHING; ERYTHEMA; EDEMA; RHINOPHYMA; papules; and ocular symptoms. It may occur at any age but typically after age 30. There are various subtypes of rosacea: erythematotelangiectatic, papulopustular, phymatous, and ocular (National Rosacea Society's Expert Committee on the Classification and Staging of Rosacea, J Am Acad Dermatol 2002; 46:584-7).Dermatomycoses: Superficial infections of the skin or its appendages by any of various fungi.Epidermolysis Bullosa: Group of genetically determined disorders characterized by the blistering of skin and mucosae. There are four major forms: acquired, simple, junctional, and dystrophic. Each of the latter three has several varieties.Keratosis: Any horny growth such as a wart or callus.Dermatologic Agents: Drugs used to treat or prevent skin disorders or for the routine care of skin.Pemphigoid, Bullous: A chronic and relatively benign subepidermal blistering disease usually of the elderly and without histopathologic acantholysis.Lupus Erythematosus, Cutaneous: A form of lupus erythematosus in which the skin may be the only organ involved or in which skin involvement precedes the spread into other body systems. It has been classified into three forms - acute (= LUPUS ERYTHEMATOSUS, SYSTEMIC with skin lesions), subacute, and chronic (= LUPUS ERYTHEMATOSUS, DISCOID).Skin Pigmentation: Coloration of the skin.Dermatitis, Allergic Contact: A contact dermatitis due to allergic sensitization to various substances. These substances subsequently produce inflammatory reactions in the skin of those who have acquired hypersensitivity to them as a result of prior exposure.Ultraviolet Therapy: The use of ultraviolet electromagnetic radiation in the treatment of disease, usually of the skin. This is the part of the sun's spectrum that causes sunburn and tanning. Ultraviolet A, used in PUVA, is closer to visible light and less damaging than Ultraviolet B, which is ionizing.Capripoxvirus: A genus of the family POXVIRIDAE, subfamily CHORDOPOXVIRINAE, comprising poxviruses infecting sheep, goats, and cattle. Transmission is usually mechanical by arthropods, but also includes contact, airborne routes, and non-living reservoirs (fomites).National Institute of Arthritis and Musculoskeletal and Skin Diseases (U.S.): Component of the NATIONAL INSTITUTES OF HEALTH. It supports research into the causes, treatment, and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research; and the dissemination of information on research progress. It was established in 1986.Blister: Visible accumulations of fluid within or beneath the epidermis.Tinea Pedis: Dermatological pruritic lesion in the feet, caused by Trichophyton rubrum, T. mentagrophytes, or Epidermophyton floccosum.Malassezia: A mitosporic fungal genus that causes a variety of skin disorders. Malassezia furfur (Pityrosporum orbiculare) causes TINEA VERSICOLOR.PUVA Therapy: Photochemotherapy using PSORALENS as the photosensitizing agent and ultraviolet light type A (UVA).Scabies: A contagious cutaneous inflammation caused by the bite of the mite SARCOPTES SCABIEI. It is characterized by pruritic papular eruptions and burrows and affects primarily the axillae, elbows, wrists, and genitalia, although it can spread to cover the entire body.Erythema: Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of causes.Administration, Topical: The application of drug preparations to the surfaces of the body, especially the skin (ADMINISTRATION, CUTANEOUS) or mucous membranes. This method of treatment is used to avoid systemic side effects when high doses are required at a localized area or as an alternative systemic administration route, to avoid hepatic processing for example.Non-Fibrillar Collagens: A family of structurally-related short-chain collagens that do not form large fibril bundles.Mycobacterium ulcerans: A slow-growing mycobacterium that infects the skin and subcutaneous tissues, giving rise to indolent BURULI ULCER.Lichen Planus: An inflammatory, pruritic disease of the skin and mucous membranes, which can be either generalized or localized. It is characterized by distinctive purplish, flat-topped papules having a predilection for the trunk and flexor surfaces. The lesions may be discrete or coalesce to form plaques. Histologically, there is a "saw-tooth" pattern of epidermal hyperplasia and vacuolar alteration of the basal layer of the epidermis along with an intense upper dermal inflammatory infiltrate composed predominantly of T-cells. Etiology is unknown.Vitiligo: A disorder consisting of areas of macular depigmentation, commonly on extensor aspects of extremities, on the face or neck, and in skin folds. Age of onset is often in young adulthood and the condition tends to progress gradually with lesions enlarging and extending until a quiescent state is reached.Dermis: A layer of vascularized connective tissue underneath the EPIDERMIS. The surface of the dermis contains innervated papillae. Embedded in or beneath the dermis are SWEAT GLANDS; HAIR FOLLICLES; and SEBACEOUS GLANDS.Hand DermatosesScleroderma, Localized: A term used to describe a variety of localized asymmetrical SKIN thickening that is similar to those of SYSTEMIC SCLERODERMA but without the disease features in the multiple internal organs and BLOOD VESSELS. Lesions may be characterized as patches or plaques (morphea), bands (linear), or nodules.Skin Physiological Processes: Biological activities and functions of the SKIN.Desmoglein 1: A desmosomal cadherin that is an autoantigen in the acquired skin disorder PEMPHIGUS FOLIACEUS.Skin, Artificial: Synthetic material used for the treatment of burns and other conditions involving large-scale loss of skin. It often consists of an outer (epidermal) layer of silicone and an inner (dermal) layer of collagen and chondroitin 6-sulfate. The dermal layer elicits new growth and vascular invasion and the outer layer is later removed and replaced by a graft.Skin Diseases, Eczematous: Any of a variety of eruptive skin disorders characterized by erythema, oozing, vesiculation, and scaling. Etiology is varied.Ichthyosis: Any of several generalized skin disorders characterized by dryness, roughness, and scaliness, due to hypertrophy of the stratum corneum epidermis. Most are genetic, but some are acquired, developing in association with other systemic disease or genetic syndrome.Skin Diseases, Metabolic: Diseases of the skin associated with underlying metabolic disorders.Military HygieneDermatitis, Contact: A type of acute or chronic skin reaction in which sensitivity is manifested by reactivity to materials or substances coming in contact with the skin. It may involve allergic or non-allergic mechanisms.Skin Abnormalities: Congenital structural abnormalities of the skin.Keratoderma, Palmoplantar: Group of mostly hereditary disorders characterized by thickening of the palms and soles as a result of excessive keratin formation leading to hypertrophy of the stratum corneum (hyperkeratosis).Acantholysis: Separation of the prickle cells of the stratum spinosum of the epidermis, resulting in atrophy of the prickle cell layer. It is seen in diseases such as pemphigus vulgaris (see PEMPHIGUS) and DARIER DISEASE.Desmoglein 3: A desmosomal cadherin that is an autoantigen in the acquired skin disorder PEMPHIGUS VULGARIS.Patch Tests: Skin tests in which the sensitizer is applied to a patch of cotton cloth or gauze held in place for approximately 48-72 hours. It is used for the elicitation of a contact hypersensitivity reaction.Staphylococcal Skin Infections: Infections to the skin caused by bacteria of the genus STAPHYLOCOCCUS.Mite Infestations: Infestations with arthropods of the subclass ACARI, superorder Acariformes.Administration, Cutaneous: The application of suitable drug dosage forms to the skin for either local or systemic effects.Agricultural Workers' Diseases: Diseases in persons engaged in cultivating and tilling soil, growing plants, harvesting crops, raising livestock, or otherwise engaged in husbandry and farming. The diseases are not restricted to farmers in the sense of those who perform conventional farm chores: the heading applies also to those engaged in the individual activities named above, as in those only gathering harvest or in those only dusting crops.Erythema Multiforme: A skin and mucous membrane disease characterized by an eruption of macules, papules, nodules, vesicles, and/or bullae with characteristic "bull's-eye" lesions usually occurring on the dorsal aspect of the hands and forearms.Ectoparasitic Infestations: Infestations by PARASITES which live on, or burrow into, the surface of their host's EPIDERMIS. Most ectoparasites are ARTHROPODS.Hidradenitis Suppurativa: A chronic suppurative and cicatricial disease of the apocrine glands occurring chiefly in the axillae in women and in the groin and anal regions in men. It is characterized by poral occlusion with secondary bacterial infection, evolving into abscesses which eventually rupture. As the disease becomes chronic, ulcers appear, sinus tracts enlarge, fistulas develop, and fibrosis and scarring become evident.Scalp DermatosesPoxviridae Infections: Virus diseases caused by the POXVIRIDAE.Dermatitis, Irritant: A non-allergic contact dermatitis caused by prolonged exposure to irritants and not explained by delayed hypersensitivity mechanisms.Pyoderma Gangrenosum: An idiopathic, rapidly evolving, and severely debilitating disease occurring most commonly in association with chronic ulcerative colitis. It is characterized by the presence of boggy, purplish ulcers with undermined borders, appearing mostly on the legs. The majority of cases are in people between 40 and 60 years old. Its etiology is unknown.Dermatitis, Exfoliative: The widespread involvement of the skin by a scaly, erythematous dermatitis occurring either as a secondary or reactive process to an underlying cutaneous disorder (e.g., atopic dermatitis, psoriasis, etc.), or as a primary or idiopathic disease. It is often associated with the loss of hair and nails, hyperkeratosis of the palms and soles, and pruritus. (From Dorland, 27th ed)Buruli Ulcer: A lesion in the skin and subcutaneous tissues due to infections by MYCOBACTERIUM ULCERANS. It was first reported in Uganda, Africa.Warts: Benign epidermal proliferations or tumors; some are viral in origin.Ultraviolet Rays: That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.Keratolytic Agents: Agents that soften, separate, and cause desquamation of the cornified epithelium or horny layer of skin. They are used to expose mycelia of infecting fungi or to treat corns, warts, and certain other skin diseases.Keratin-14: A type I keratin that is found associated with the KERATIN-5 in the internal stratified EPITHELIUM. Mutations in the gene for keratin-14 are associated with EPIDERMOLYSIS BULLOSA SIMPLEX.Scleroderma, Diffuse: A rapid onset form of SYSTEMIC SCLERODERMA with progressive widespread SKIN thickening over the arms, the legs and the trunk, resulting in stiffness and disability.Urticaria: A vascular reaction of the skin characterized by erythema and wheal formation due to localized increase of vascular permeability. The causative mechanism may be allergy, infection, or stress.Dermatomyositis: A subacute or chronic inflammatory disease of muscle and skin, marked by proximal muscle weakness and a characteristic skin rash. The illness occurs with approximately equal frequency in children and adults. The skin lesions usually take the form of a purplish rash (or less often an exfoliative dermatitis) involving the nose, cheeks, forehead, upper trunk, and arms. The disease is associated with a complement mediated intramuscular microangiopathy, leading to loss of capillaries, muscle ischemia, muscle-fiber necrosis, and perifascicular atrophy. The childhood form of this disease tends to evolve into a systemic vasculitis. Dermatomyositis may occur in association with malignant neoplasms. (From Adams et al., Principles of Neurology, 6th ed, pp1405-6)Carcinoma, Basal Cell: A malignant skin neoplasm that seldom metastasizes but has potentialities for local invasion and destruction. Clinically it is divided into types: nodular, cicatricial, morphaic, and erythematoid (pagetoid). They develop on hair-bearing skin, most commonly on sun-exposed areas. Approximately 85% are found on the head and neck area and the remaining 15% on the trunk and limbs. (From DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1471)Keratins: A class of fibrous proteins or scleroproteins that represents the principal constituent of EPIDERMIS; HAIR; NAILS; horny tissues, and the organic matrix of tooth ENAMEL. Two major conformational groups have been characterized, alpha-keratin, whose peptide backbone forms a coiled-coil alpha helical structure consisting of TYPE I KERATIN and a TYPE II KERATIN, and beta-keratin, whose backbone forms a zigzag or pleated sheet structure. alpha-Keratins have been classified into at least 20 subtypes. In addition multiple isoforms of subtypes have been found which may be due to GENE DUPLICATION.Langerhans Cells: Recirculating, dendritic, antigen-presenting cells containing characteristic racket-shaped granules (Birbeck granules). They are found principally in the stratum spinosum of the EPIDERMIS and are rich in Class II MAJOR HISTOCOMPATIBILITY COMPLEX molecules. Langerhans cells were the first dendritic cell to be described and have been a model of study for other dendritic cells (DCs), especially other migrating DCs such as dermal DCs and INTERSTITIAL DENDRITIC CELLS.Alopecia Areata: Loss of scalp and body hair involving microscopically inflammatory patchy areas.Neurodermatitis: An extremely variable eczematous skin disease that is presumed to be a response to prolonged vigorous scratching, rubbing, or pinching to relieve intense pruritus. It varies in intensity, severity, course, and morphologic expression in different individuals. Neurodermatitis is believed by some to be psychogenic. The circumscribed or localized form is often referred to as lichen simplex chronicus.Drug Eruptions: Adverse cutaneous reactions caused by ingestion, parenteral use, or local application of a drug. These may assume various morphologic patterns and produce various types of lesions.Skin Diseases, Papulosquamous: A group of dermatoses with distinct morphologic features. The primary lesion is most commonly a papule, usually erythematous, with a variable degree of scaling on the surface. Plaques form through the coalescing of primary lesions.Emollients: Oleagenous substances used topically to soothe, soften or protect skin or mucous membranes. They are used also as vehicles for other dermatologic agents.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Desmogleins: A group of desmosomal cadherins with cytoplasmic tails that resemble those of classical CADHERINS.Autoimmune Diseases: Disorders that are characterized by the production of antibodies that react with host tissues or immune effector cells that are autoreactive to endogenous peptides.Foot Dermatoses: Skin diseases of the foot, general or unspecified.Antipruritics: Agents, usually topical, that relieve itching (pruritus).Chemokine CCL27: A CC-type chemokine with specificity for CCR10 RECEPTORS. It is constitutively expressed in the skin and may play a role in T-CELL trafficking during cutaneous INFLAMMATION.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Immunoglobulin E: An immunoglobulin associated with MAST CELLS. Overexpression has been associated with allergic hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).Dermcidins: 47-amino acid peptides secreted by ECCRINE GLANDS and having a role in innate cutaneous defense, being antimicrobial to some pathogenic BACTERIA. They are overexpressed by some primary BREAST CANCER cells. They are derived from 110 residue PROTEIN PRECURSORS.Parapsoriasis: The term applied to a group of relatively uncommon inflammatory, maculopapular, scaly eruptions of unknown etiology and resistant to conventional treatment. Eruptions are both psoriatic and lichenoid in appearance, but the diseases are distinct from psoriasis, lichen planus, or other recognized dermatoses. Proposed nomenclature divides parapsoriasis into two distinct subgroups, PITYRIASIS LICHENOIDES and parapsoriasis en plaques (small- and large-plaque parapsoriasis).Coal Tar: A by-product of the destructive distillation of coal used as a topical antieczematic. It is an antipruritic and keratoplastic agent used also in the treatment of psoriasis and other skin conditions. Occupational exposure to soots, tars, and certain mineral oils is known to be carcinogenic according to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985) (Merck Index, 11th ed).Ichthyosis, Lamellar: A chronic, congenital ichthyosis inherited as an autosomal recessive trait. Infants are usually born encased in a collodion membrane which sheds within a few weeks. Scaling is generalized and marked with grayish-brown quadrilateral scales, adherent at their centers and free at the edges. In some cases, scales are so thick that they resemble armored plate.Folliculitis: Inflammation of follicles, primarily hair follicles.Alopecia: Absence of hair from areas where it is normally present.Methoxsalen: A naturally occurring furocoumarin compound found in several species of plants, including Psoralea corylifolia. It is a photoactive substance that forms DNA ADDUCTS in the presence of ultraviolet A irradiation.Sebaceous Glands: Small, sacculated organs found within the DERMIS. Each gland has a single duct that emerges from a cluster of oval alveoli. Each alveolus consists of a transparent BASEMENT MEMBRANE enclosing epithelial cells. The ducts from most sebaceous glands open into a HAIR FOLLICLE, but some open on the general surface of the SKIN. Sebaceous glands secrete SEBUM.Dog Diseases: Diseases of the domestic dog (Canis familiaris). This term does not include diseases of wild dogs, WOLVES; FOXES; and other Canidae for which the heading CARNIVORA is used.Ointments: Semisolid preparations used topically for protective emollient effects or as a vehicle for local administration of medications. Ointment bases are various mixtures of fats, waxes, animal and plant oils and solid and liquid hydrocarbons.Wound Healing: Restoration of integrity to traumatized tissue.Autoantibodies: Antibodies that react with self-antigens (AUTOANTIGENS) of the organism that produced them.Inflammation: A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function.Larva Migrans: Infections caused by nematode larvae which never develop into the adult stage and migrate through various body tissues. They commonly infect the skin, eyes, and viscera in man. Ancylostoma brasiliensis causes cutaneous larva migrans. Toxocara causes visceral larva migrans.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.Irritants: Drugs that act locally on cutaneous or mucosal surfaces to produce inflammation; those that cause redness due to hyperemia are rubefacients; those that raise blisters are vesicants and those that penetrate sebaceous glands and cause abscesses are pustulants; tear gases and mustard gases are also irritants.Desmosomes: A type of junction that attaches one cell to its neighbor. One of a number of differentiated regions which occur, for example, where the cytoplasmic membranes of adjacent epithelial cells are closely apposed. It consists of a circular region of each membrane together with associated intracellular microfilaments and an intercellular material which may include, for example, mucopolysaccharides. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990; Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Stevens-Johnson Syndrome: Rare cutaneous eruption characterized by extensive KERATINOCYTE apoptosis resulting in skin detachment with mucosal involvement. It is often provoked by the use of drugs (e.g., antibiotics and anticonvulsants) or associated with PNEUMONIA, MYCOPLASMA. It is considered a continuum of Toxic Epidermal Necrolysis.Antiparasitic Agents: Drugs used to treat or prevent parasitic infections.Hyperkeratosis, Epidermolytic: A form of congenital ichthyosis inherited as an autosomal dominant trait and characterized by ERYTHRODERMA and severe hyperkeratosis. It is manifested at birth by blisters followed by the appearance of thickened, horny, verruciform scales over the entire body, but accentuated in flexural areas. Mutations in the genes that encode KERATIN-1 and KERATIN-10 have been associated with this disorder.Ivermectin: A mixture of mostly avermectin H2B1a (RN 71827-03-7) with some avermectin H2B1b (RN 70209-81-3), which are macrolides from STREPTOMYCES avermitilis. It binds glutamate-gated chloride channel to cause increased permeability and hyperpolarization of nerve and muscle cells. It also interacts with other CHLORIDE CHANNELS. It is a broad spectrum antiparasitic that is active against microfilariae of ONCHOCERCA VOLVULUS but not the adult form.Skin Diseases, Vascular: Skin diseases affecting or involving the cutaneous blood vessels and generally manifested as inflammation, swelling, erythema, or necrosis in the affected area.Lichen Sclerosus et Atrophicus: A chronic inflammatory mucocutaneous disease usually affecting the female genitalia (VULVAR LICHEN SCLEROSUS) and BALANITIS XEROTICA OBLITERANS in males. It is also called white spot disease and Csillag's disease.Dermatitis Herpetiformis: Rare, chronic, papulo-vesicular disease characterized by an intensely pruritic eruption consisting of various combinations of symmetrical, erythematous, papular, vesicular, or bullous lesions. The disease is strongly associated with the presence of HLA-B8 and HLA-DR3 antigens. A variety of different autoantibodies has been detected in small numbers in patients with dermatitis herpetiformis.Onchocerciasis: Infection with nematodes of the genus ONCHOCERCA. Characteristics include the presence of firm subcutaneous nodules filled with adult worms, PRURITUS, and ocular lesions.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Hair Follicle: A tube-like invagination of the EPIDERMIS from which the hair shaft develops and into which SEBACEOUS GLANDS open. The hair follicle is lined by a cellular inner and outer root sheath of epidermal origin and is invested with a fibrous sheath derived from the dermis. (Stedman, 26th ed) Follicles of very long hairs extend into the subcutaneous layer of tissue under the SKIN.Impetigo: A common superficial bacterial infection caused by STAPHYLOCOCCUS AUREUS or group A beta-hemolytic streptococci. Characteristics include pustular lesions that rupture and discharge a thin, amber-colored fluid that dries and forms a crust. This condition is commonly located on the face, especially about the mouth and nose.Biopsy: Removal and pathologic examination of specimens in the form of small pieces of tissue from the living body.Injections, Intradermal: The forcing into the skin of liquid medication, nutrient, or other fluid through a hollow needle, piercing the top skin layer.Molluscum Contagiosum: A common, benign, usually self-limited viral infection of the skin and occasionally the conjunctivae by a poxvirus (MOLLUSCUM CONTAGIOSUM VIRUS). (Dorland, 27th ed)Bowen's Disease: A persistent progressive non-elevated red scaly or crusted plaque which is due to an intradermal carcinoma and is potentially malignant. Atypical squamous cells proliferate through the whole thickness of the epidermis. The lesions may occur anywhere on the skin surface or on mucosal surfaces. The cause most frequently found is trivalent arsenic compounds. Freezing, cauterization or diathermy coagulation is often effective. (From Rook et al., Textbook of Dermatology, 4th ed, pp2428-9)Autoantigens: Endogenous tissue constituents that have the ability to interact with AUTOANTIBODIES and cause an immune response.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Erythrokeratodermia Variabilis: An autosomal dominant skin disease characterized by transient and variable noninflammatory ERYTHEMA and hyperkeratosis. It has been associated with mutations in the genes that code for CONNEXINS. Erythrokeratodermia variabilis inherited in an autosomal recessive fashion has also been reported. Affected individuals often develop PALMOPLANTAR KERATODERMA.Mycosis Fungoides: A chronic, malignant T-cell lymphoma of the skin. In the late stages, the LYMPH NODES and viscera are affected.Epidermolysis Bullosa, Junctional: Form of epidermolysis bullosa having onset at birth or during the neonatal period and transmitted through autosomal recessive inheritance. It is characterized by generalized blister formation, extensive denudation, and separation and cleavage of the basal cell plasma membranes from the basement membrane.Arthritis, Psoriatic: A type of inflammatory arthritis associated with PSORIASIS, often involving the axial joints and the peripheral terminal interphalangeal joints. It is characterized by the presence of HLA-B27-associated SPONDYLARTHROPATHY, and the absence of rheumatoid factor.Intermediate Filament Proteins: Filaments 7-11 nm in diameter found in the cytoplasm of all cells. Many specific proteins belong to this group, e.g., desmin, vimentin, prekeratin, decamin, skeletin, neurofilin, neurofilament protein, and glial fibrillary acid protein.Cytokines: Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.Dermatologic Surgical Procedures: Operative procedures performed on the SKIN.T-Lymphocytes: Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.Epidermolysis Bullosa Simplex: A form of epidermolysis bullosa characterized by serous bullae that heal without scarring. Mutations in the genes that encode KERATIN-5 and KERATIN-14 have been associated with several subtypes of epidermolysis bullosa simplex.Lymphoma, T-Cell, Cutaneous: A group of lymphomas exhibiting clonal expansion of malignant T-lymphocytes arrested at varying stages of differentiation as well as malignant infiltration of the skin. MYCOSIS FUNGOIDES; SEZARY SYNDROME; LYMPHOMATOID PAPULOSIS; and PRIMARY CUTANEOUS ANAPLASTIC LARGE CELL LYMPHOMA are the best characterized of these disorders.Photosensitivity Disorders: Abnormal responses to sunlight or artificial light due to extreme reactivity of light-absorbing molecules in tissues. It refers almost exclusively to skin photosensitivity, including sunburn, reactions due to repeated prolonged exposure in the absence of photosensitizing factors, and reactions requiring photosensitizing factors such as photosensitizing agents and certain diseases. With restricted reference to skin tissue, it does not include photosensitivity of the eye to light, as in photophobia or photosensitive epilepsy.Mice, Inbred C57BLScleroderma, Systemic: A chronic multi-system disorder of CONNECTIVE TISSUE. It is characterized by SCLEROSIS in the SKIN, the LUNGS, the HEART, the GASTROINTESTINAL TRACT, the KIDNEYS, and the MUSCULOSKELETAL SYSTEM. Other important features include diseased small BLOOD VESSELS and AUTOANTIBODIES. The disorder is named for its most prominent feature (hard skin), and classified into subsets by the extent of skin thickening: LIMITED SCLERODERMA and DIFFUSE SCLERODERMA.Ear: The hearing and equilibrium system of the body. It consists of three parts: the EXTERNAL EAR, the MIDDLE EAR, and the INNER EAR. Sound waves are transmitted through this organ where vibration is transduced to nerve signals that pass through the ACOUSTIC NERVE to the CENTRAL NERVOUS SYSTEM. The inner ear also contains the vestibular organ that maintains equilibrium by transducing signals to the VESTIBULAR NERVE.Skin Cream: A water-soluble medicinal preparation applied to the skin.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Croton Oil: Viscous, nauseating oil obtained from the shrub Croton tiglium (Euphorbaceae). It is a vesicant and skin irritant used as pharmacologic standard for skin inflammation and allergy and causes skin cancer. It was formerly used as an emetic and cathartic with frequent mortality.Photomicrography: Photography of objects viewed under a microscope using ordinary photographic methods.Mice, Hairless: Mutant strains of mice that produce little or no hair.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Anti-Allergic Agents: Agents that are used to treat allergic reactions. Most of these drugs act by preventing the release of inflammatory mediators or inhibiting the actions of released mediators on their target cells. (From AMA Drug Evaluations Annual, 1994, p475)Interleukin-17: A proinflammatory cytokine produced primarily by T-LYMPHOCYTES or their precursors. Several subtypes of interleukin-17 have been identified, each of which is a product of a unique gene.Sarcoptes scabiei: A species of mite that causes SCABIES in humans and sarcoptic mange in other animals. Specific variants of S. scabiei exist for humans and animals, but many have the ability to cross species and cause disease.Anti-Inflammatory Agents: Substances that reduce or suppress INFLAMMATION.Ichthyosis Vulgaris: Most common form of ICHTHYOSIS characterized by prominent scaling especially on the exterior surfaces of the extremities. It is inherited as an autosomal dominant trait.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Dinitrofluorobenzene: Irritants and reagents for labeling terminal amino acid groups.Histamine H1 Antagonists: Drugs that selectively bind to but do not activate histamine H1 receptors, thereby blocking the actions of endogenous histamine. Included here are the classical antihistaminics that antagonize or prevent the action of histamine mainly in immediate hypersensitivity. They act in the bronchi, capillaries, and some other smooth muscles, and are used to prevent or allay motion sickness, seasonal rhinitis, and allergic dermatitis and to induce somnolence. The effects of blocking central nervous system H1 receptors are not as well understood.Collagen Type VII: A non-fibrillar collagen involved in anchoring the epidermal BASEMENT MEMBRANE to underlying tissue. It is a homotrimer comprised of C-terminal and N-terminal globular domains connected by a central triple-helical region.Histamine H1 Antagonists, Non-Sedating: A class of non-sedating drugs that bind to but do not activate histamine receptors (DRUG INVERSE AGONISM), thereby blocking the actions of histamine or histamine agonists. These antihistamines represent a heterogenous group of compounds with differing chemical structures, adverse effects, distribution, and metabolism. Compared to the early (first generation) antihistamines, these non-sedating antihistamines have greater receptor specificity, lower penetration of BLOOD-BRAIN BARRIER, and are less likely to cause drowsiness or psychomotor impairment.Telepathology: Transmission and interpretation of tissue specimens via remote telecommunication, generally for the purpose of diagnosis or consultation but may also be used for continuing education.Medicine, Traditional: Systems of medicine based on cultural beliefs and practices handed down from generation to generation. The concept includes mystical and magical rituals (SPIRITUAL THERAPIES); PHYTOTHERAPY; and other treatments which may not be explained by modern medicine.Darier Disease: An autosomal dominantly inherited skin disorder characterized by warty malodorous papules that coalesce into plaques. It is caused by mutations in the ATP2A2 gene encoding SERCA2 protein, one of the SARCOPLASMIC RETICULUM CALCIUM-TRANSPORTING ATPASES. The condition is similar, clinically and histologically, to BENIGN FAMILIAL PEMPHIGUS, another autosomal dominant skin disorder. Both diseases have defective calcium pumps (CALCIUM-TRANSPORTING ATPASES) and unstable desmosomal adhesion junctions (DESMOSOMES) between KERATINOCYTES.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Epidermolysis Bullosa Dystrophica: Form of epidermolysis bullosa characterized by atrophy of blistered areas, severe scarring, and nail changes. It is most often present at birth or in early infancy and occurs in both autosomal dominant and recessive forms. All forms of dystrophic epidermolysis bullosa result from mutations in COLLAGEN TYPE VII, a major component fibrils of BASEMENT MEMBRANE and EPIDERMIS.Cathelicidins: Antimicrobial cationic peptides with a highly conserved amino terminal cathelin-like domain and a more variable carboxy terminal domain. They are initially synthesized as preproproteins and then cleaved. They are expressed in many tissues of humans and localized to EPITHELIAL CELLS. They kill nonviral pathogens by forming pores in membranes.Immunosuppressive Agents: Agents that suppress immune function by one of several mechanisms of action. Classical cytotoxic immunosuppressants act by inhibiting DNA synthesis. Others may act through activation of T-CELLS or by inhibiting the activation of HELPER CELLS. While immunosuppression has been brought about in the past primarily to prevent rejection of transplanted organs, new applications involving mediation of the effects of INTERLEUKINS and other CYTOKINES are emerging.Antimicrobial Cationic Peptides: Small cationic peptides that are an important component, in most species, of early innate and induced defenses against invading microbes. In animals they are found on mucosal surfaces, within phagocytic granules, and on the surface of the body. They are also found in insects and plants. Among others, this group includes the DEFENSINS, protegrins, tachyplesins, and thionins. They displace DIVALENT CATIONS from phosphate groups of MEMBRANE LIPIDS leading to disruption of the membrane.Otitis Externa: Inflammation of the OUTER EAR including the external EAR CANAL, cartilages of the auricle (EAR CARTILAGE), and the TYMPANIC MEMBRANE.Plant Extracts: Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.Occupational Exposure: The exposure to potentially harmful chemical, physical, or biological agents that occurs as a result of one's occupation.Chronic Disease: Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.Allergens: Antigen-type substances that produce immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).Cat Diseases: Diseases of the domestic cat (Felis catus or F. domesticus). This term does not include diseases of the so-called big cats such as CHEETAHS; LIONS; tigers, cougars, panthers, leopards, and other Felidae for which the heading CARNIVORA is used.Onchocerca volvulus: A species of parasitic nematodes widely distributed throughout central Africa and also found in northern South America, southern Mexico, and Guatemala. Its intermediate host and vector is the blackfly or buffalo gnat.Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Melanocytes: Mammalian pigment cells that produce MELANINS, pigments found mainly in the EPIDERMIS, but also in the eyes and the hair, by a process called melanogenesis. Coloration can be altered by the number of melanocytes or the amount of pigment produced and stored in the organelles called MELANOSOMES. The large non-mammalian melanin-containing cells are called MELANOPHORES.Phototherapy: Treatment of disease by exposure to light, especially by variously concentrated light rays or specific wavelengths.Proteinase Inhibitory Proteins, Secretory: Peptides and proteins found in BODILY SECRETIONS and BODY FLUIDS that are PROTEASE INHIBITORS. They play a role in INFLAMMATION, tissue repair and innate immunity (IMMUNITY, INNATE) by inhibiting endogenous proteinases such as those produced by LEUKOCYTES and exogenous proteases such as those produced by invading microorganisms.Immunoglobulin G: The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Mice, Inbred BALB CMycobacterium Infections, Nontuberculous: Infections with nontuberculous mycobacteria (atypical mycobacteria): M. kansasii, M. marinum, M. scrofulaceum, M. flavescens, M. gordonae, M. obuense, M. gilvum, M. duvali, M. szulgai, M. intracellulare (see MYCOBACTERIUM AVIUM COMPLEX;), M. xenopi (littorale), M. ulcerans, M. buruli, M. terrae, M. fortuitum (minetti, giae), M. chelonae.Hydroxychloroquine: A chemotherapeutic agent that acts against erythrocytic forms of malarial parasites. Hydroxychloroquine appears to concentrate in food vacuoles of affected protozoa. It inhibits plasmodial heme polymerase. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p970)Mice, Mutant Strains: Mice bearing mutant genes which are phenotypically expressed in the animals.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Psoralens: Linear furanocoumarins which are found in many PLANTS, especially UMBELLIFERAE and RUTACEAE, as well as PSORALEA from which they were originally discovered. They can intercalate DNA and, in an UV-initiated reaction of the furan portion, alkylate PYRIMIDINES, resulting in PHOTOSENSITIVITY DISORDERS.Papilloma: A circumscribed benign epithelial tumor projecting from the surrounding surface; more precisely, a benign epithelial neoplasm consisting of villous or arborescent outgrowths of fibrovascular stroma covered by neoplastic cells. (Stedman, 25th ed)Edema: Abnormal fluid accumulation in TISSUES or body cavities. Most cases of edema are present under the SKIN in SUBCUTANEOUS TISSUE.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.