Seborrhoeic dermatitis and Pityrosporum ovale: a cultural and immunological study.

Seborrhoeic dermatitis is associated with Pityrosporum ovale, but the exact role of the organism is not clarified. In order to study this connection we have investigated 30 patients with seborrhoeic dermatitis with quantitative culture for P. ovale, serum IgG antibodies against P. ovale and lipid measurements. We compared the patients with 60 healthy individuals and found no significant difference in the number of P. ovale or serum antibodies. The lipid content on the skin was significantly higher in the patient group (p = 0.0001). There was no difference in the number of P. ovale in lesions compared to healthy skin in the patient group. This study support our theory that an abnormal reaction in the skin to P. ovale causes the inflammation and the number of P. ovale is of minor importance.