Pityriasis versicolor manifests as slightly scaly, hypopigmented macules which appear on the upper trunk and shoulders and may spread to the lower trunk, upper arms, neck and face. Hands and lower limbs are usually not involved. The earlier lesions are usually located around the hair follicles, but soon these merge with each other to form large areas. This disease is rare in children, but common in young adults.
The lesions are asymptomatic and may not be discovered for long periods.
Some patients report aggravations in summer. Systemic corticosteroids have also been observed to lead to aggravations.
If untreated,the disease may persist indefinitely or show spontaneous remissions and exacerbations.
Sometimes, particularly in fair skinned individuals, the lesions are brownish scaly macules.
The disease is caused by an organism called Malassezia furfur which can be demonstrated in the scrapings from the lesions but cannot be grown in artificial media.
This organism is now believed to be the hyphal phase of Pityrosporon orbiculare which is normally present on the skin.
Treatment of Pityriasis Versicolor
These lesions should be treated with local applications of a lotion containing three percent salicylic acid, three percent benzoic acid, 25 percent alcohol and 25 percent sodium thiosulphate in distilled water. This lotion is to be applied all over the lesions daily at night and should be continued for two to three months.
The organism tends to disappear within two to four weeks but the color of the skin takes much longer to return to normal.
An alternative method of treatment consists of local applications of selenium sulphide shampoo for 15 minutes before bath daily once a day for the first week and then on alternate days during the following two or three weeks; occasionally, however, the patient may not be able to tolerate such frequent applications of selenium sulphide and may develop a local reaction.
Local applications of five percent lactic acid/sodium lactate, two percent miconazole or clotrimazole twice a day are also useful. Sometimes, the lesions recur at a later date in which case, the same treatment can be repeated.
Systemic antifungals may be given in severe cases of pityriasis versicolor.