Papules

Papules are a class of skin lesion characterized by a circumscribed, solid elevation of the skin that measures less than 1 centimeter in diameter. Unlike vesicles or pustules, papules do not contain fluid. They may be erythematous (red), skin-colored, or pigmented, and can be dome-shaped, flat-topped, or rounded. Papules arise from localized epidermal or superficial dermal proliferation, inflammation, or infiltration of cells and can occur alone or in clusters.

Papules are a common feature of many dermatologic conditions. Examples include acne vulgaris, where inflammatory papules appear on the face and trunk; dermatitis such as contact or atopic dermatitis with itchy red papules; lichen planus, which presents as shiny, violaceous papules often on wrists or ankles; molluscum contagiosum, which forms dome-shaped, central-umbilicated papules; warts caused by human papillomavirus; and folliculitis.

Diagnosis is typically clinical, based on appearance and distribution. In uncertain cases, dermoscopy or skin biopsy may be used to distinguish papules from other lesions. Histologically, papules show epidermal hyperplasia or dermal inflammatory infiltrates without fluid-filled spaces.

Management focuses on the underlying condition. Treatments may include topical corticosteroids for inflammatory papules, retinoids or keratolytics for acne or warts, antibiotics for bacterial involvement, or observation for molluscum contagiosum as lesions often resolve spontaneously.

Prognosis varies with cause; many papules resolve with treatment or spontaneously, while some persist until adolescence or require ongoing management.