Pityrosporum orbiculare
Summary
Infections caused by Pityrosporum occur in the hair follicles
Route Of Exposure
Allergen Exposure
Pityrosporum is a lipophilic yeast form of Malassezia furfur usually considered to be a non-pathogenic saprophyte and can be found in the skin of more than 80% of healthy adults but is rare in young children. Infections caused by Pityrosporum occur in the hair follicles.
Clinical Relevance
There appears to be an intimate relation recently described between IgE sensitization to P. orbiculare and severe atopic eczema. These authors found a strong relationship between atopic eczema and the occurrence of IgE antibodies to the mold and concluded that these antibodies may be pathogenetically important in at least some patients with atopic eczema.
Kieffer et al. found IgE antibodies to Pityrosporum in patients with atopic dermatitis (AD) but found no evidence of immediate or delayed hypersensitivity in the seborrheic dermatitis. Rokugo et al. also found positive prick tests to Porbiculare extract in 75% of their AD patients.
Review
Pityrosporum is a lipophilic yeast form of Malassezia furfur usually considered to be a non-pathogenic saprophyte and can be found in the skin of more than 80% of healthy adults but is rare in young children. Infections caused by Pityrosporum occur in the hair follicles.
There appears to be an intimate relation recently described between IgE sensitization to P. orbiculare and severe atopic eczema. These authors found a strong relationship between atopic eczema and the occurrence of IgE antibodies to the mold and concluded that these antibodies may be pathogenetically important in at least some patients with atopic eczema. Kieffer et al. found IgE antibodies to Pityrosporum in patients with atopic dermatitis (AD) but found no evidence of immediate or delayed hypersensitivity in the seborrheic dermatitis. Rokugo et al. also found positive prick tests to Porbiculare extract in 75% of their AD patients. They concluded that the mold plays a role as an allergen derived from the host environment in the exacerbation of the skin lesions of AD.
References
- Nordvall LS, Johansson S. IgE antibodies to Pityrosporum orbiculate in children with atopic diseases. Acta Paediatr Scand 1990;70(3):343-8.
- Kieffer M, Bergbrant IM, Faergemann J, Jemec GB, Ottevanger V, Stahl Skov B, Svejgaard E. Immune reactions to Pityrosporum ovale in adult patients with atopic and seborrheic dermatitis. J Am Acad Dermatol 1990;22(5, Pt 1):739-42.
- Rokugo M, Tagami H, Usuba Y, Tomita Y. Contact sensitivity to Pityrosporum ovale in patients with atopic dermatitis. Arch Dermatol 1990;126(5):627-32.