In simple terms, Melasma can be caused by hormones. Scientifically, Melanocyte-stimulating hormone describes a group of hormones produced by the anterior pituitary gland, hypothalamus and skin cells. There are different forms of MSH that belong to a group called melanocortins. The group includes adrenocorticotropic (ACTH), a-MSH, b-MSH and y-MSH. They are all peptides and are cleavage products of the precursor peptide called proopiomelanocortin (POMC).When there is an increase in MSH, the skin may become darker in areas. MSH along with other sex hormones increase during pregnancy and peak during the third trimester. There are also links between thyroid hormones and melasma, though this is still a controversial topic. Whatever the triggering factor in the development of melasma, there are people who have a predisposition toward both melasma and thyroid autoimmunity.
See below for tips on identifying clinical features of melasma:
- Centrofacial pattern: forehead, cheeks, nose and upper lips
- Malar pattern: cheeks and nose
- Lateral cheek pattern
- Mandibular pattern: jawline
- Redden or inflamed forms of melasma also known as erythrosis pigmentosa facial.
- Brachial melasma that affects shoulders and upper arms
- Epidermal melasma
- Dermal melasma
- Mixed melasma
The characteristic appearance of melasma allows for an easy diagnosis. Though with the many different forms of melasma and the many types of manifestation we need to understand which melasma we are treating.
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Yours in Skin