Some cells present in skin give colour to it. Most of us have brown skin, which has a natural tendency to turn dark on sun-exposure or after injury. Sunlight-exposure darkens the skin. Some cosmetics contain a potent photo-sensitizer, which causes dark patches on the sides of neck and behind the ears. Some drugs like Sulfas, Tetracycline, Diuretics can cause pigmentation in sensitive individuals.

Nylon brush, which is used to clean utensils, is used by many people to clean their skin. Daily brushing gives brown-black colour on bony prominences.

In winter, tanned skin comes back to it's original colour.

Fungus infections can cause white patches on chest and face.

Leucoderma (vitiligo) is complete loss of pigmentation. About 1-2% of general population has vitiligo. In early stages, vitiligo can be cured or controlled with Allopathic medicines.

Dr. Kiran Godse Skin Specialist Laksh-Deep Hospital