There are three main types of skin hypo pigmentation:
Is characterized by depigmented areas, usually sharply demarcated and often symmetric, caused by a lack of melanocytes (cells that are responsible for the skin color). Depigmentation may involve one or two spots or may cover most of the skin surface. Hair in vitiliginous areas is usually white. Skin lesions are accentuated under Wood's light.
Vitiligo is an autoimmune condition that causes skin depigmentation. It takes the form of skin white spots with a sharp margin and a milk white color. The normal texture and sensation of the skin are preserved. No scaling occurs.
Follows healing of certain inflammatory disorders (ex. dermatitis), burns, and skin infections. It is related to scars and atrophic skin. Skin pigmentation is reduced, but it may not be milk-white as in vitiligo. Spontaneous repigmentation may sometimes occur.
Leucoderma is just another name for vitiligo: "leuco" means white and "derma" refers to the skin (Greek root).
Yes, people it can be associated to other autoimmune disorders.
Is a rare autosomal recessive inherited disorder in which melanocytes are present but do not form melanin (substance that colors the skin). There are various forms. In tyrosinase-negative albinism, the hair is white, the skin pale, and the eyes pink; nystagmus and errors of refraction are common. They should avoid sunlight, use sunglasses, and during daylight hours use a sunscreen with an SPF of >= 15.
Apart from these three main types of hypopigmentation, a common skin condition that usually causes skin depigmentation is known as Pityriasis.