Melasma is condition of abnormally darkened skin that occurs mostly on the face of pregnant women. This condition is also known as Chloasma faciei or the mask of pregnancy. However, melasma can also occur in women that are not pregnant and is always related to some form of hormonal imbalance often a result of hormone replacement therapy or the use of birth control pills.
Melasma usually manifests as darkened areas located on your upper cheek, nose, lips, upper lip, and forehead. These hyperpigmented areas can look like discrete freckles or may appear as patches which may develop gradually over time.
Melasma is thought to result from the excessive stimulation of melanocytes (pigment-producing cells) under the influence of female sex hormones such as estrogen and progesterone. These hormone sensitive melanocytes will consequently lead to irregular skin coloration especially when these areas of skin are exposed to sunlight.
Melasma is most prevalent in women that have light brown skin and have been exposed to intense levels of sunlight. There is also some genetic predisposition to melasma.
Any condition that increases melanocyte stimulating hormone (MSH) can increase your risk of developing melasma. MSH is produced in a specific part of your brain known as the pro-opio- melano-cortin receptor (POMC). Your POMC is influenced by thyroid disease, sun exposure, various forms of stress and adrenal disease.
A specific form of melasma known as Melasma Suprarenale can be a symptom of Addison’s disease (adrenal cortex failure) that results in excessive production of adrenal cotico tropic hormone (ACTH) which as affects your POMC.
It is likely that any form of excessive stress that leads to overstimulation of ACTH can contribute to the development of melasma.