Light areas on the skin of a 29 year old man with the fungal infection pityriasis versicolor, also known as tinea versicolor. This skin condition is caused by the yeast Malassezia furfur, which is normally found on the skin without causing any problems. However, in warm humid environments it may proliferate and cause an infection. It most commonly affects the back, upper arms, chest and neck, causing light patches and occasionally scaly skin and itching. Treatment is with antifungal cream.