Skin surface lipids in HIV-positive patients with and without seborrheic dermatitis.
Seborrheic dermatitis (SD) is a frequent complication of infection with the human immunodeficiency virus (HIV). Most studies examining the cause of SD have concentrated on the roles of Pityrosporum ovale and sebaceous lipids. Previous studies of skin surface lipid from patients with SD have produced conflicting results, with some authors reporting an abnormal lipid composition and others finding little or no abnormality. The composition of skin surface lipid was studied in 15 HIV-positive and 10 HIV-negative men with SD, in 14 HIV-positive men without SD, and in 16 unaffected controls. Total lipids were extracted from unaffected forehead skin into petroleum ether and separated into lipid classes by thin layer chromatography. The lipid classes were quantitated by densitometry after charring with sulfuric acid. Patients, HIV-positive with SD, had significantly lower proportions of free fatty acid (FFA) and higher levels of triglyceride than normal controls. Patients, HIV-positive without SD, had a significantly increased proportion of FFA compared to HIV-positive patients with SD. Patients with SD, both HIV-positive and HIV-negative, had a similar pattern of skin surface lipid. Levels of FFA were lower and those of triglyceride higher than in the patients unaffected by SD, whether HIV-positive or not. There was no significant difference found between groups in free cholesterol, wax esters, and squalene. Abnormalities of skin surface lipid composition may play a part in the development of SD in both HIV-positive and HIV-negative men.