Allergic contact dermatitis is an inflammatory process induced by direct contact of the skin of a sensitized individual to an allergen.

Leukocytoclastic vasculitis (LCV) is a histopathologic term used to describe diseases clinically classified as “cutaneous small vessel vasculitis,” the most common type of vasculitis manifesting in the skin.

A condition of persons of any age, but particularly children with a genetic proclivity for allergic rhinitis and conjunctivitis, and allergic asthma.

A papule, sometimes eroded, ulcerated, crusted, or keratotic, on a helix or antehelix consequent to the effects of persistent trauma.

An inflammatory process characterized by symmetrical distribution, especially on the skin of the scalp, overlying the scapulae and the sacrum, on the buttocks, and on the extensor surface of the extremities, of clusters of urticarial papules, papulovesicles, and vesicles that are so intensely pruritic that they soon are scratched away, leaving in the wake erosions, ulcers, hemorrhagic crusts, and eventually pigmented macules and scars.

Dermatitis (and/or panniculitis) induced artificially and deliberately by a patient and characterized clinically by findings unlike those of any “authentic” disease, for example, by lesions that have sharply angulated margins, lesions that are artificially linear, and ulcers that have a punched-out appearance, all of these changes occurring on sites that are within easy reach of manipulating hands.

An inflammatory process of unknown cause consisting of pruritic coin-shaped lesions of different sizes and made up of vesicles that soon are scratched away, leaving erosions, ulcerations, and crusts as residua.

An inflammatory process, but not a vasculitis, that involves the legs especially with purpuric macules and subtle papules (Schamberg’s disease), lichenoid papules (lichenoid purpura of Gougerot-Blum), and scaly papules (eczematid-like purpura of Doucas and Kapetanakis), all of which seem to be variants of the same basic pathologic process.

An inflammatory process that results from either topical or systemic sensitization coupled with the effects of ultraviolet light.

An inflammatory process that represents the combined effects of a toxic substance applied topically or administered systemically in combination with the effects of ultraviolet light, the result being a caricature of sunburn.

An inflammatory process that consists of tiny papules covered by prominent scales and localized typically to the “seborrheic region,” namely, scalp, forehead, eyebrows, malar eminences, paranasal and nasolabial folds, and retroauricular zone, and sometimes the chest and axillary vault.