Erythematous

Erythematous describes redness of the skin or mucous membranes resulting from increased blood flow in the superficial dermis, usually due to dilation of capillaries (hyperemia) involved in an inflammatory process. The term derives from Greek erythros, meaning red, with a suffix indicating a marked condition. Erythema may be blanchable when pressed, and the affected area is often warmer than surrounding skin.

clinically, erythematous skin appears red or pink and may be diffuse or localized. The redness can be accompanied by warmth, mild swelling, itching, or tenderness. In darker skin tones, erythema may be less obvious and appear as a purplish or brownish discoloration rather than a bright red.

Causes of erythema are broad and include infections (such as cellulitis or candidal mucosal involvement), inflammatory skin conditions (eczema, contact dermatitis, psoriasis), rosacea, sunburn, and other phototoxic or photoallergic reactions. It can follow irritation from chemicals or friction, burns, or radiation. Drug reactions, including erythema multiforme, and systemic inflammatory or vasodilatory states can also produce erythematous changes. Erythema may be part of a normal physiological response to heat or exercise.

Diagnosis relies on history and physical examination. New or persistent, enlarging, non-blanching, or painful red lesions, especially with fever, spreading symptoms, or systemic signs, warrant further evaluation to exclude infection or other pathology. In uncertain cases, dermatologic or medical consultation and, if needed, biopsy or laboratory testing may be employed.

Management focuses on treating the underlying cause and symptomatic relief. This may include avoiding irritants, applying moisturizers, using cool compresses, and, for inflammatory dermatoses, topical corticosteroids. Antibiotics are indicated for bacterial infections; more extensive therapy is guided by the diagnosis.