Dermatite atopica: Un ruolo patogenetico per l'allergia al Pityrosporum orbiculare?

A pathogenetic role for IgE-mediated allergy to the lipophilic yeast Pityrosporum orbiculare (PO), a saprophyte of normal skin, has been proposed in some cases of atopic dermatitis. In this study the presence of specific IgE was evaluated in vitro by the CAP System in 72 children with atopic dermatitis in an active phase and in 54 non-atopic children (RAST-negative for common food and inhalant allergens). 83% of the patients had specific IgE for at least one of the common food or inhalant allergens tested and in 54% the eczematous lesions involved the skin of the head and/or neck. Sensitization to PO was found in 22% of the 72 patients, but was absent in all 54 non-atopic controls. Specific IgE levels were low (>0.35-0.7 Ku/l) in 8/16 and reached modest levels (>0.7-3.5 Ku/l) in the remaining 8. The frequency of sensitization to PO was similar in the presence or absence of involvement of the skin of the head and/or neck. These data together with those of the literature suggest a role of sensitization to PO in at least some cases of infantile atopic dermatitis and the possible advantage of specific treatment in such cases.