How to treat tinea versicolor like a dermatologist. Tinea versicolor is a common fungal skin infection that presents as light to tan/brown spots on the back or chest and can last for years without treatment. It is caused by the same yeast/fungus that causes dandruff, so using an anti-dandruff shampoo, like Nizoral, can help clear up this rash. To use, lather Nizoral shampoo on your chest or back, leave it on for about 5 minutes, then rinse off. Repeat 2-3 times per week. If you are prone to gett