Pityrosporum and Candida-yeasts are opportunistic pathogens and
infections require predisposing factors. These factors are also of major importance in treatment and the reason for recurrence and sometimes chronicity of the disease caused by these yeasts. Pityrosporum orbiculare and P.ovale are both lipophilic, probably identical, and both are members of the normal human cutaneous flora. In
pityriasis versicolor they change from the blastospore form to the mycelial form. My favourite treatment for
pityriasis versicolor is
propylene glycol 50% in water applied with a gauze pad twice daily for 2 weeks. This will clear 95-100%. Other treatment modalities are:
zinc pyrithione shampoo,
selenium sulfide shampoo and the
imidazoles. For extensive cases, patients who frequently relapse, and
infections refractary to other treatments
ketoconazole orally may be an effective alternative both therapeutically and prophylactically. In another disease caused by these yeasts, Pityrosporum
folliculitis, both
propylene glycol and
ketoconazole are effective. Although Candida species are only seldom found on normal-looking skin predisposing factors are still the main reason for disease. Under the influence of these factors the organism changes from the blastospore to the mycelial form. The main predisposing factors important to control are: occlusion, underlying
skin diseases,
diabetes mellitus and immunodeficiency diseases. The
imidazoles in a cream vehicle are very effective for many
infections and applied for 2-3 weeks they will clear most lesions. The addition of a
corticosteroid to the
imidazole will not shorten the time of treatment but will give a more prompt symptomatic relief. In extensive cutaneous lesions and lesions refractary to other treatments
ketoconazole is an effective alternative.