Arthropods are common in the environment. Although many can bite or sting humans, only a few infest humans. Arachnids (mites) are the most common, parasitizing humans and animals by burrowing into the skin and depositing eggs within the skin. Scabies…
Erythema multiforme (EM), reactive infectious mucocutaneous eruption (RIME), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN) are acute hypersensitivity reactions characterized by cutaneous and mucosal necrosis. These syndromes represent a hypersensitivity reaction to a precipitating cause, usually infectious organisms or…
Vascular anomalies can be divided into two major categories: tumors and malformations. Vascular tumors are characterized by hypercellularity, proliferation, and growth. Vascular malformations, however, are developmental defects derived from the capillary, venous, arterial, or lymphatic vessels. In contrast to hemangiomas,…
Birthmark is a term that describes congenital anomalies of the skin. It should not be used as a definitive diagnosis because congenital skin lesions vary greatly in their appearance and prognosis. The differential diagnosis of various birthmarks is listed in…
Etiology Seborrheic dermatitis is a common, chronic inflammatory disease that has different clinical presentations at different ages. Seborrheic dermatitis classically presents in infants as cradle cap or dermatitis in the intertriginous areas of the axillae, groin, antecubital and popliteal fossae,…
Etiology and Epidemiology Inflammation in the top layers of the skin, caused by direct contact with a substance, is divided into two subtypes: irritant contact dermatitis and allergic contact dermatitis. Irritant contact dermatitis is observed after the skin surface is…
Etiology Atopic dermatitis is a chronic inflammatory disease with no known cure. It is associated with significant psychosocial morbidity and decreased health-related quality of life. For many affected individuals, atopic dermatitis is the skin manifestation of atopy accompanied by asthma…
Etiology Acne vulgaris (or acne) is a chronic inflammatory disorder that affects areas with the greatest concentration of sebaceous glands, such as the face, chest, and back. Gender, age, genetic factors, and environment are all major contributing pathogenic factors. Stress…
Approximately one in three Americans of any age has at least one recognizable skin disorder at any time. The most common cutaneous diseases encountered in community settings are dermatophytosis, acne vulgaris, seborrheic dermatitis, atopic dermatitis (eczema), verrucae (warts), tumors, psoriasis,…