seborrhea

Seborrhea refers to excessive sebum production by the sebaceous glands, leading to oily, shiny skin or scalp. It is not a disease in itself but a trait influenced by androgens and genetics. Sebum production tends to be highest in adolescence and may persist into adulthood, and it can be affected by hormones, medications, and individual skin type.

Seborrheic dermatitis is the inflammatory manifestation of seborrhea. It is characterized by oily skin with flaky scales, redness, and itching, most often affecting the scalp (dandruff), eyebrows, eyelashes, nasolabial folds, and the chest. In infants, cradle cap is a mild form of this condition.

Pathophysiology is multifactorial. Androgens stimulate sebaceous glands, increasing sebum production, while colonization with Malassezia yeast on oily skin appears to contribute to inflammation in susceptible individuals. Skin barrier function, immune responses, and environmental factors such as season, stress, and humidity also influence flare frequency.

Diagnosis is clinical; laboratory tests are not routinely required. The main differential diagnoses include acne vulgaris, psoriasis, rosacea, contact dermatitis, and other sebaceous conditions. Atypical, widespread, or treatment-resistant lesions may warrant further evaluation.

Treatment focuses on reducing oiliness and controlling inflammation. For general oily skin, regular washing with mild, nonirritating cleansers and noncomedogenic moisturizers is advised. Seborrheic dermatitis is treated with antifungal shampoos or creams containing ketoconazole, ciclopirox, zinc pyrithione, or selenium sulfide, often used on the scalp and affected areas; topical corticosteroids are used short-term for inflammation, with calcineurin inhibitors as alternatives. In infants, cradle cap generally improves with gentle washing; more persistent cases should be managed by a clinician.

Prognosis and management: Seborrhea and seborrheic dermatitis are typically chronic with relapses. Ongoing management aims to control symptoms and reduce recurrence. Regular skin care, adherence to medicated shampoos or topical therapies, and avoidance of harsh products help; severe or treatment-resistant cases require medical evaluation.