Hi,
Tinea versicolor is a chronic fungal infection of the skin. It is a relatively common skin infection caused by a fungus and may be seen at the back, underarms, upper arms, legs, chest, and neck. The condition is most common in adolescent and is associated with hot climates.
The main symptom is persistent patches of discolored skin with sharp borders and fine scales, often merging together to form a larger patch . The patches are often dark reddish-tan in color. Affected areas do not darken in the sun and may have associated increased sweating or itching. Diagnosis is through a skin scraping and subsequent examination under a microscope. Treatment consists of anti-fungal medicines applied to the skin. Over-the-counter dandruff shampoos applied to the skin for 10 minutes each day in the shower may also help treat the lesions.
Take care and regards.
Just thought I should add that the patch is really made up of smaller patches that come together in the center and that I'm not sure that the hair grows faster there.