Seborrhea means excessive oily secretions. Seborrhoeic dermatitis is a chronic scaly inflammatory eruption affecting areas rich in sebaceous glands.
Evidence suggests a role of Malasezia furfur/Pityrosporum ovale, a yeast that colonises the skin of patients with seborrhoeic dermatitis; however, it is unclear if this is the cause or effect of the condition. Seborrheic dermatitis is common in patients with HIV infection and may be a presenting feature.
The lesions appear pinkish due to mild erythema and scaly due to increased epidermal proliferation. The commonest areas affected are the eyebrows and around the eyes extending into the scalp. The areas around the nose and upper lip are also affected. In babies a widespread lesion of the scalp (cradle cap) is seen, and in the elderly lesions are often more diffuse.
Seborrhoeic dermatitis is treated with a combination of low-potency steroids and topical antifungal creams/shampoos.