More common in women 20 to 50 years of age, melasma is, in part, caused by prolonged exposure to ultraviolet light from either sunlight or tanning booths, although there are other contributing factors. Considered a common skin condition, it often appears somewhere on the face, although it may also appear on any other part of your body that is regularly exposed to sunlight or some other form of UV light. Being mindful of your exposure to sun is one of the most effective ways to prevent the condition from developing.
Link to Pregnancy Melasma often occurs during pregnancy in the second or third trimester. In fact, it is so commonly associated with pregnancy that it is often referred to as "the mask of pregnancy" (the medical term for melasma related to pregnancy is chloasma gravidarum). Women with darker complexions are more likely to develop it while pregnant. It is caused by a sharp increase in estrogen levels. The extra estrogen stimulates the excess production of a dark brown or black pigment called melanin, which results in visible discoloration on the skin.
Other than pregnancy, contributing factors to melasma may include the use of contraceptives and certain hormone drugs and treatments such as hormone replacement therapy. The skin condition may also be triggered be medical conditions that result in hormone changes or produce imbalances in hormone levels. There is some evidence it may be triggered by certain dyes or perfumes or by prolonged periods of stress or anxiety. Melasma may run in families, suggesting that it may be hereditary.
Since melasma is also linked to sun exposure, an important step you can take to prevent it, or minimize your risk of experiencing a breakout, is to use sunscreen when outdoors. The general recommendation is to use a sunscreen with a sun protection factor (SPF) of 30 or higher. No sunscreen offers complete protection and there is no evidence that choosing a product with a higher SPF will offer more benefits than what you'd get with SPF 30, but you do want to avoid sunscreens with a lower SPF. Sunscreens that are "water resistant" are not "waterproof" and will need to be replied.
Minimizing your exposure to UV rays should also include reducing your time outdoors on especially bright and sunny days if you're prone to outbreaks of melasma. Sunlight is usually strongest between the hours of 10am and 4pm. If you are unable to avoid being in the sun during this time, make an effort to seek shade as much as possible or wear wide hats to shield your skin. Also avoid tanning beds and sunlamps. Doing so will also reduce your risk of developing skin cancer.
Melasma is not curable, but it is also not cancerous and there is no evidence it will change into skin cancer. People in climates that naturally receive more sun or places where there are more days with direct sunlight are also susceptible to developing the condition. Melasma cannot be passed along to others through contact, nor is it a condition related to an infection or associated with seasonal allergies. The condition often appears during summer months and occurs less frequently during winter months.