Overview of Pigmentation Disorders
Pigmentation disorders involve hypopigmentation, depigmentation, or hyperpigmentation. Areas may be focal or diffuse. In hypopigmentation, pigment is decreased, whereas in depigmentation, pigment is completely lost, leaving white skin.
Focal hypopigmentation is most commonly a consequence of
Focal hypopigmentation or depigmentation is also a feature of vitiligo (which may involve large areas of skin), leprosy, nutritional deficiencies (kwashiorkor), and genetic conditions (eg, tuberous sclerosis, piebaldism, Waardenburg syndrome).
Diffuse hypopigmentation or depigmentation is most often caused by
Hyperpigmentation typically occurs after inflammation due to various causes. This postinflammatory hyperpigmentation is usually focal in distribution. Hyperpigmentation may also be caused by a systemic disorder, drug, or cancer; distribution is usually more diffuse.