Revista de Dermatologia e Doenças Dermatológicas

Melasma and Endocrine Disorders

Abstract

Ilaria Muller and Aled Rees

Melasma is an acquired and chronic disorder characterized by a localized symmetrical hypermelanosis of the face or, less frequently, involving the neck and forearms. It occurs with a high prevalence during pregnancy, especially during the second half of the gestational period, and in women taking exogenous female hormones. Melasma has also rarely been described in males, especially those affected by primary hypogonadism or taking estrogens for prostatic cancer. Melasma thus appears to be pathologically related to female sex hormones, but this is not consistently reflected in high circulating levels of estrogens or progesterone. This implies that other factors are likely to be relevant, including genetic predisposition, exposure to ultraviolet light, cosmetics and some medications. Melanocortins play a key role in melanogenesis but no cases of melasma have been described in pituitary or adrenal diseases, including those associated with an increase in serum ACTH. An association between melasma and thyroid disorders has been reported only once and not confirmed in subsequent studies. The skin is both a source of, and a target for vitamin D; however, no cases of melasma have been described in association with disordered vitamin D production. Finally, clinicians should distinguish the localized hypermelanosis of melasma from general hyperpigmentation occurring in pregnancy or in pituitary and adrenal diseases associated with a raised serum ACTH.