Melasma

What it is

Melasma is a progressive, macular, nonscaling hypermelanosis of skin exposed to the sun: hyperpigmented macules in sun-exposed areas, typically involving the face and the dorsal forearms.

The term chloasma is sometimes used interchangeably, but more specifically describes the appearance of melasma during pregnancy.

How it presents

There are three common patterns of melasma, and each is named for the part of the face involved: centrofacial, malar and mandibular.

The case built on the mandibular pattern runs like this. A 46-year-old female with a past medical history of polycystic ovary syndrome and migraine headaches has bilateral, hyperpigmented patches along her mandible. The patches are asymptomatic, but they bother her cosmetically and seem to be darkening.

So what marks it out is what it does not do. It does not itch, it does not scale, it is bilateral, and it sits on skin exposed to the sun.