Many people who have been traveling in warm climates or those who sweat a lot can experience a fungal infection called tinea versicolor. Warm, moist environments are ideal conditions for this type of fungus to proliferate. This skin condition is characterized by red, brown and white scaly patches that are most commonly found on the chest, neck, back and arms, and skin discoloration can also occur. Tinea versicolor may be helped by applying an antidandruff shampoo with a medicated ingredient, such as pyrithione zinc, on the affected area for a couple of minutes several times a week. Because the infection tends to become chronic, seek advice from your doctor.