Hyperpigmentation is the increase in the natural color of the skin. It is the darkening of an area of skin or nails caused by increased melanin.
History of skin inflammation (post-inflammatory hyperpigmentation).
Use of certain medications.
Endocrine diseases such as Addison's disease.
Hemochromatosis (iron overload).
Sun exposure sun damage.
Inflammation, or other skin injuries, including those related to acne Vulgaris.
1. Cushing's disease or other excessive adrenocorticotropic hormone (ACTH) production.
2. Acanthosis nigricans – hyperpigmentation of intertriginous areas associated with insulin resistance.
3. Melasma, also known as chloasma – patchy hyperpigmentation often found in pregnant women.
4. Linea nigra – a hyperpigmented line found on the abdomen during pregnancy.