Pityriasis capitisor Seborrhoeic dermatitis (SD) is a common, chronic, relapsing condition characterized by reddish scaly patches and variable itching. It affects the scalp, face and central chest-areas with a high density of sebaceous(oil) glands. On scalp without inflammation it isreferred to as dandruff or pityriasis capitis.
Malassezia (Pityrosprum) yeasts are associated with SD and cause dandruff through indirect and possibly immunological mechanisms.
Dandruff affects up to half of the world’s population post puberty.
Dandruff (SD) occurs more commonly in winter and usually improves with sun exposure.
SD (dandruff) onsets in early adult life with localized inflammation and superficial flaking of the skin. It runs a chronic relapsing course. Facial involvement with fine flaking of skin with mild redness is seen around nasolabial folds,ear creases, eyelids, medial eyebrows, and in the external ear canals. Scalp involvement ranges from mild flaking to inflammatory dermatitis with thicker, yellowish, greasy scales and crusts. Involvement of the anterior eyelid margin may occur in SD and presents with flaky debris on the eyelashes.
SD is generally considered to be a chronic complaint, with flares and requires long term treatment.
There is no definitive cure for SD (dandruff). Long term maintenance treatment is required but some patients only use treatment intermittently for acute, symptomatic flares. Topical antifungals shampoos are the mainstay of therapy due to their safety in all ages.
Rook’s Textbook of Dermatology, Ninth Edition