Chloasma–the mask of pregnancy.
Bolanca I, Bolanca Z, Kuna K, Vuković A, Tuckar N, Herman R, Grubisić G. Coll Antropol. 2008 Oct;32 Suppl 2:139-41. Review.
- Melasma (chloasma, pregnancy mask) can affect 50 to 70% of pregnant women and presents as symmetric hyperpigmented macules which can be located on cheeks, upper lip, chin, forehead
- The cause remains largely unknown but there are known etiological factors:
- Hormonal factors play a role.
- Estrogen, progesterone and melanocyte stimulating hormone (MSH) are all increased during the third trimester of pregnancy.
- However normal levels are found in women not having had children with normal levels of estrogen and MSH.
- Melasma can occur in women taking estrogen and progesterone containing oral contraceptive pills.
- The hypothesis where progesterone might play a most important role is that postmenopausal women who are given hormonal replacement therapy (HRT) with progesterone develop melasma whereas those who are given only estrogen do not.
- UVB and UVA as well as visible light are independently capable of stimulating melanogenesis.
Source of information: here