IgE antibodies to Malassezia furfur, M. sympodialis and Pityrosporum orbiculare in patients with atopic dermatitis, seborrheic eczema or pityriasis versicolor, and identification of respective allergens.

Malassezia yeasts may be a trigger factor for atopic dermatitis. Following the recent reclassification of the genus, the presence of specific IgE antibodies was examined in the sera of patients with atopic dermatitis (n = 223), pityriasis versicolor (n = 83), seborrheic eczema (n = 50) and hymenoptera allergy (n = 39) and in controls without skin diseases (n = 50). In addition to using the commercially available radioallergosorbent test (RAST) for Pityrosporum orbiculare couplings were also made against the reference strains for M. furfur and M. sympodialis. To characterize the specificity and molecular weight of corresponding epitopes identical material was used for production of an immunoblot. Despite high total levels of IgE, controls and patients with pityriasis versicolor showed no specific IgE antibodies. Six patients (12%) with seborrheic eczema were positive while 78 patients (35%) with atopic dermatitis had specific IgE antibodies in higher RAST classes that differed between the Malassezia species. The molecular weights of the main antigens of M. sympodialis and M. furfur were determined to be 15, 22, 30, 37, 40, 58, 79, 92, 99 and 124 kDa and 15, 25, 27, 43, 58, 92, 99 and 107 kDa, respectively. Evaluated according to the location of their disease, patients with head and neck lesions most frequently showed Malassezia-specific IgE antibodies. However, there were differences between the Malassezia species tested, the previously used strain P. orbiculare being assignable to the species M. sympodialis.