A diagnosis that I regularly make in and out of the clinic is melasma. While it's a satisfying one to offer to patients, I keep my mouth shut when I notice it on strangers or acquaintances, although I'm curious whether they've noticed the pigmentation changes to their face and whether they know the cause.
Melasma is an acquired increase in pigmentation to exposed body areas, usually the face. It's most often caused by the birth control pill or pregnancy, and is precipitated by sun exposure. It is not painful or itchy - it's a cosmetic issue only.
* Photo from the Color Atlas and Synopsis of Clinical Dermatology. (That volume is quite delightful as a coffee table book, by the way. Guests pore over the images; they can't help themselves.)
Melasma is also known as chloasma or "the mask of pregnancy," and can be striking, as in the patient pictured above. But in my experience, melasma more often presents as a subtler darkening of the cheeks, or as a brownish smudge along the upper lip. If they notice it at all, patients usually attribute it to aging, freckling or tanning.
The macules or patches can range from light brown to black in colour, have well-defined margins, and are distributed symmetrically. The most common locations are the cheeks (especially below the eyes), the forehead and bridge of nose, and the upper lip.
Darker-skinned individuals and those living in sunny climates are more prone to this skin condition. The incidence among Vancouverites with fair skin is much lower than among Cubans, say. In northern climes melasma may be seasonal, fading over the darker winter months and become more pronounced again in summer.
Discontinuation of the pill or delivery of the baby usually causes the pigmentation to fade over months. (With subsequent pregnancies, the pigmentation tends to return, and to progressively darken.)
Avoiding sun exposure can prevent the onset or worsening of melasma. Sunscreens with an SPF of at least 30 and containing a physical sunblock such as titanium oxide or zinc oxide should be applied liberally and consistently.
Prescription skin bleaching creams can be effective. Hydroquinone 3-4% cream, sometimes in conjunction with tretinoin, may be prescribed for weeks or months.
Patients are impressed when, at the first visit, I know their contraceptive choice the second I lay eyes on them. I've made deductions about some friends and family as well, but haven't yet tested their reactions.
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