The carriage of Malassezia furfur serovars A, B and C in patients with pityriasis versicolor, seborrhoeic dermatitis and controls

Abstract

The aetiological role of Malassezia furfur in various dermatoses is controversial. The role of the three serovars of M. furfur in Malassezia-associated diseases has not been investigated. This study measured population densities of M. furfur serovars A, B and C, propionibacteria and Micrococcaceae on the chest, back, forehead, left and right cheeks of 10 patients with pityriasis versicolor, and 10 age- and sex-matched controls; and 10 patients with seborrhoeic dermatitis, and 10 age- and sex-matched controls. The population densities of M. furfur, propionibacteria and Micrococcaceae did not vary at a given site between patients and the corresponding control subjects. Malassezia furfur serovar A was found to be the predominant isolate on the chest and back of all four groups, but there was no difference in the distribution of serovars on the forehead and cheeks. No serovar was specifically associated with lesional skin in either disease. Thus, this data indicated that there was no difference in either the total population density of M. furfur or the distribution of serovars on lesional skin compared with control skin in either pityriasis versicolor or seborrhoeic dermatitis.

Pityrosporum species as a cause of allergy and infection

“…Two reports found a reduced lymphocyte stimulation reaction when lymphocytes from patients with seborrheic dermatitis were stimulated with P. ovale extract (33,34). However, another study found an increase in both lymphocyte transformation response and leukocyte migration inhibition assay (18). As with pityriasis versicolor, the preparation of the antigen extract may, explain the difference in results.…”

“…Other studies have found raised antibody titers (31) or no differences in titers (32). Two reports found a reduced lymphocyte stimulation reaction when lymphocytes from patients with seborrheic dermatitis were stimulated with P. ovale extract (33,34).…”

Atopic Dermatitis and Fungi

“…Seborrheic dermatitis is characterized by red scaly lesions located predominantly on the scalp, face, and upper trunk. There are now many studies indicating that the Malassezia yeasts play an important role in seborrheic dermatitis (6,14,36,41,42,43). Many of these are treatment studies which describe the effectiveness of antimycotics, paralleled by a reduction in number of the Malassezia yeasts, whereas recolonization leads to a recurrence of seborrheic dermatitis.…”

“…The increased incidence of seborrheic dermatitis in patients with immunosuppressive disorders suggests that the relationship between Malassezia and the immune system is important, but the exact mechanism involved is still unknown. Studies designed to investigate this mechanism in patients with seborrheic dermatitis fall into four areas (6,43): the humoral response to Malassezia, lymphocyte transformation response to Malassezia extract, T helper (CD4)/T suppressor (CD8) cell ratios, and cytokine responses. However, studies in all of these areas have given inconsistent results, and the local reaction in the skin may give a better answer.…”

Immunology of Diseases Associated withMalasseziaSpecies

“…Ashbee et al (27) carried out a study of the microbiology of PV and took samples from sites on the trunk and head of 10 patients. They measured the total amount of Malassezia and the amount of each serovar (A, B, and C) at each site in an attempt to determine if any particular serovar was associated with the lesions of the disease.…”