Hyperpigmentation is a common, usually harmless condition in which patches of skin become darker in color than the normal surrounding skin .
Hyperpigmentation may be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris. People with darker Asian, Mediterranean or African skin tones are also more prone to hyperpigmentation, especially if they have excess sun exposure.
Hyperpigmentation is associated with a number of diseases or conditions, including :
- Addison's disease and other sources of adrenal insufficiency, in which hormones that stimulate melanin synthesis, such as melanocyte-stimulating hormone (MSH), are frequently elevated.
- Cushing's disease or other excessive adrenocorticotropic hormone (ACTH) production, because MSH production is a byproduct of ACTH synthesis from proopiomelanocortin (POMC).
- Acanthosis nigricans – hyperpigmentation of intertriginous areas associated with insulin resistance.
- Melasma, also known as chloasma – patchy hyperpigmentation often found in pregnant women.
- Linea nigra – a hyperpigmented line found on the abdomen during pregnancy.
- Peutz-Jeghers syndrome – an autosomal dominant disorder characterized by hyperpigmented macules on the lips and oral mucosa and gastrointestinal polyps.
- Exposure to certain chemicals such as salicylic acid, bleomycin, and cisplatin.
- Smoker's melanosis
- Celiac disease
- Cronkite-Canada syndrome
- Tinea fungal infections such as ringworm
- Haemochromatosis - a common but debilitating genetic disorder characterized by the chronic accumulation of iron in the body.
- Mercury poisoning - particularly cases of cutaneous exposure resulting from the topical application of mercurial ointments or skin-whitening creams.
- Aromatase deficiency
- Nelson's syndrome
treatment of hyperpigmentation may include hydroquinone, tretinoin (Retinol), topical glucocorticoids, and licorice extract , and treating the main cause if there is any .
References: formulamedical ,aocd ,wikipedia