A substance called melanin is responsible for the colour of the skin. But illness, injury, and a few conditions may cause changes in the pigmentation due to increased or decreased melanin production. When the skin gets darkened, it's called hyperpigmentation, while discolouration is termed as hypopigmentation. Conditions such as Addison's disease and pregnancy induce more production of melanin resulting in hyperpigmentation. Exposure to sunlight is said to aggravate the hyperpigmented areas. Certain drugs too, cause hyperpigmentation. Hyperpigmentation during pregnancy is called Melasma where dark brown patches appear on the skin. Melasma usually goes away after pregnancy and can also be treated with hydroquinone creams, especially when it affects the men which is a rarity. Hypopigmentation is the condition where melanin production is insufficient. Most common conditions are: Vitiligo – An autoimmune disorder in which the pigment-producing cells are damaged. Treatments include cosmetic cover-ups, corticosteroid creams, and ultraviolet light treatments. Albinism – This is a rare inherited disorder that is caused by the lack of an enzyme essential for melanin production. There is a complete lack of pigmentation in skin, hair, and eyes in this condition. There is no cure for this disorder, and it can occur in any race but is more prevalent in Caucasians. Persons with this disorder should always use sunscreen as they are prone to skin cancer and sun damage. Sometimes pigmentation loss happens because of skin damage due to skin infection, blisters, burns, or other damage to the skin. More often, this is not permanent and the skin repairs by itself.