What causes melasma?

Melasma is a common pigmentation condition that produces brown or gray-brown patches on the face. If you have noticed these patches appearing, especially during or after pregnancy, you are far from alone. Melasma is driven by a combination of factors, mainly sun exposure, hormones, and genetics, and understanding those triggers is the first step toward controlling it. Below is a clear look at what actually causes melasma and what can be done about it.

What is melasma?

Melasma is a chronic skin condition in which certain areas of the face produce too much pigment. The patches most often appear on the cheeks, forehead, upper lip, and nose, and they tend to be roughly symmetrical, showing up in similar spots on both sides of the face. That symmetry is one of the features that helps a dermatologist tell melasma apart from other forms of discoloration, such as sun spots. If you are not sure which one you have, see our guide on how melasma differs from sun spots.

Melasma is much more common in women than in men, and it more often affects people with medium to deep skin tones. It is not harmful, but because it appears on the face and can be persistent, it often affects confidence.

The main causes of melasma

The exact cause of melasma is not fully understood. According to the American Academy of Dermatology, it likely occurs when melanocytes, the cells that give skin its color, become overactive and produce too much pigment. Several triggers are known to set that process off.

Sun exposure

Sunlight is one of the most common triggers. Ultraviolet light stimulates melanocytes to make more pigment, and even small, everyday doses, such as walking outside or driving, can bring melasma back after it has faded. Visible light, including the light from screens, may also play a role, which is why tinted mineral sunscreens are often recommended. Tanning beds produce especially strong UV and should be avoided entirely. Because the sun is such a powerful driver, daily protection matters more than any single product; see our guide to the best sunscreens for melasma.

Hormonal changes

Hormones are a major catalyst. Shifts in estrogen and progesterone can push melanocytes to overproduce pigment, which is why melasma so often appears during pregnancy, where it is sometimes called chloasma or the "mask of pregnancy." Birth control pills and postmenopausal hormone therapy can trigger it in the same way. If your melasma began during pregnancy, our post on melasma during pregnancy explains why and what your options are.

Genetics and family history

Family history is a strong risk factor. In one study of 324 melasma patients cited by the AAD, 48 percent reported having a blood relative who also had melasma. If the condition runs in your family, your own skin may be more likely to react to triggers like sun and hormones, which makes consistent prevention especially important.

Other contributing factors

Beyond the three main drivers, several everyday factors can aggravate melasma. Skin irritation is a common one: harsh scrubs, strong fragrances, and alcohol-heavy products can inflame the skin and worsen pigment, so gentle, barrier-friendly products are better. Some medications that increase sun sensitivity may also contribute, so mention any new prescriptions to your dermatologist. Heat from saunas, steam, and hot climates can aggravate melasma even without direct sun. Finally, thyroid disease has been linked to a higher risk of melasma in some people.

Who is most likely to develop melasma?

Melasma most often affects women between the ages of 20 and 40, particularly those with medium to deep skin tones and those with a family history of the condition. Pregnancy and hormonal medications raise the risk further. Knowing you fall into a higher-risk group is useful, because it makes a case for starting sun protection and gentle skincare before patches ever appear.

How melasma is treated

Melasma is manageable, though it usually requires a tailored plan rather than a single product. Sun protection is the foundation, and treatment is typically built on top of it. Topical options include the best topical ingredients for melasma, such as prescription formulations, azelaic acid, and kojic acid, along with tranexamic acid, which addresses pigment at its source. For deeper or stubborn pigment, in-office treatments such as chemical peels and lasers may be added. Because melasma can worsen if treated too aggressively, especially in darker skin tones, these decisions are best made with a dermatologist. Learn more on our professional melasma treatment page.

When to see a dermatologist

If your melasma is spreading, has not responded to over-the-counter products, or is affecting your confidence, a board-certified dermatologist can identify your specific triggers and build a plan around your skin type and the depth of your pigmentation. To learn more, visit our Melasma Treatment NYC page or schedule a consultation at .