The  skin discoloration is there year round, but its appearance is variable.  In dark complexioned people it is a lighter area of skin. In light complexioned people the involved skin is darker.  In patients who tan heavily in the summer and lose their tan in winter, the rash reverses with the tan.  Ironically, the causative fungus, of the Malassezia family of dermatophytes, lives on most people’s skin unnoticed. With infection it becomes symptomatic.

Besides the discoloration, the involved skin may itch, and if scratched, may release scale.  It typically is seen on the chest, back, neck and upper extremities, however people may also have it in the groin area. Hot, humid weather with associated sweating causes spread.  The infection promotes visits to the doctor mostly for cosmetic  reasons.  Many people think it looks or insinuates that they are dirty.  However, it can probably be isolated from almost everyone if a practiced eye swabs the skin.

Treatment can be accomplished to diminish or eradicate the rash, but it usually recurs.  Selenium, found in dandruff control shampoos such as Selsun Blue, can be applied in the shower to the skin like a body shampoo.  After lathering, the shower water should be turned off and the suds allowed to stand on the skin for five minutes before rinsing. Patients are usually advised to use these preparations every shower the first week, three times a week the second week, then once a week to keep the rash at bay.  It can be harder to control.  

There are prescription shampoo, cream, and lotion preparations which may be more efficacious.  Oral antifungal meds such as Nizoral (ketoconazole) are available in tablet form by prescription only.  One week-long method of therapy is to take the pill once a day, then wait two hours and exercise until perspiring.  The drug is thought to be released through sweat and oil glands into the skin, enhancing eradication of the fungus.  Still, it may return posing the question: why?

Most medicines kill bacteria or fungi work by providing a chemical to the target organism which is used as a building block in cell wall construction or some other critical process of reproduction.  This building block does not work and causes cell death.  To be susceptible, the medication has to be available to the target organisms during cellular division.  Since fungi divide slowly or infrequently, many dormant cells may remain on the skin after medications are washed off or metabolized.  Division occurs and the infection is reestablished.  This requires re-treatment.

Fortunately, this skin infection, for people with normal immune defenses, is not dangerous.  It is just noticeable.  Most primary care providers can recognize Tinea Versicolor at first sight. If the cause is in doubt, a simple scraping of cells placed upon a glass slide and treated with a few drops of potassium hydroxide, the KOH prep, will show, under magnification, fungal elements reminiscent of spaghetti and meatballs.  The diagnosis is clinched and accurate treatment can begin.  Your doctor can help.