Seborrheic dermatitis

Seborrheic dermatitis is a common skin condition that mainly affects areas rich in oil glands, such as the scalp, face, and upper chest. It causes redness, flaky scales, and sometimes itching or discomfort. The condition involves the skin's natural oils and a yeast called Malassezia, which can trigger inflammation. It is not contagious and tends to be chronic with periods of improvement and worsening. While it primarily affects the skin, it can impact a person's comfort and appearance. The condition is often mistaken for dandruff or eczema but has distinct features. Understanding the affected areas and symptoms helps in recognizing this common skin disorder.

Seborrheic dermatitis is a chronic inflammatory skin disorder characterized by erythematous plaques with greasy, yellowish scales predominantly in sebaceous gland-rich areas. The pathogenesis involves an abnormal immune response to the commensal yeast Malassezia species, combined with increased sebum production and epidermal barrier dysfunction. It commonly affects the scalp, face (especially nasolabial folds and eyebrows), and upper trunk. The condition is associated with factors such as stress, cold weather, neurological diseases, and immunosuppression. Histologically, it shows spongiosis, parakeratosis, and a superficial perivascular lymphocytic infiltrate. Clinically, it is significant due to its chronicity, potential for secondary infection, and impact on quality of life. It is distinct from psoriasis and atopic dermatitis by its distribution and scale characteristics.