Brown spots on skin are almost always caused by extra melanin, the pigment that gives skin its color. Most are harmless and result from sun exposure, aging, hormonal changes, or past skin inflammation. A small percentage, however, can signal something more serious like melanoma. Understanding what different types look like helps you figure out which ones to ignore and which ones deserve a closer look.
How Brown Spots Form
Your skin produces melanin as a defense against ultraviolet radiation. When UV light hits your skin, it generates free radicals that activate melanocytes, the cells responsible for pigment production. An enzyme then converts the amino acid tyrosine into melanin granules, which are distributed to surrounding skin cells to absorb further UV damage. This process is why you tan in the sun, but when melanin production becomes uneven or excessive, it leaves behind visible brown spots.
The triggers go beyond sunlight. Hormonal shifts, skin injuries, inflammation, and even certain medications can all push melanocytes into overdrive in specific areas. The type of brown spot you end up with depends largely on which trigger caused it.
Sun Spots and Age Spots
The most common brown spots are solar lentigines, often called age spots or liver spots (they have nothing to do with your liver). These flat, tan-to-dark-brown patches show up on areas that get the most sun: the backs of your hands, your forearms, face, shoulders, and chest. They’re especially common after age 50, though people with significant sun exposure can develop them earlier.
Solar lentigines are the result of years of cumulative UV exposure. Unlike a tan, which fades when you stay out of the sun, these spots reflect permanent changes in how melanin is distributed in that patch of skin. They’re flat, evenly colored, and have well-defined edges. They don’t itch, bleed, or change shape over time. While they’re cosmetically bothersome for some people, they’re benign.
Seborrheic Keratoses
These raised, waxy-looking growths are another extremely common cause of brown spots, especially in middle-aged and older adults. They range from light tan to dark brown or even black, and they have a distinctive “stuck-on” appearance, as if someone pressed a blob of candle wax onto the skin. The surface often looks rough or scaly.
Seborrheic keratoses can appear anywhere on the body except the palms and soles. They’re completely benign, though their dark color and irregular texture sometimes make people worry about skin cancer. The key giveaway is that stuck-on, slightly raised quality. They don’t need treatment unless they become irritated by clothing or you want them removed for cosmetic reasons.
Melasma and Hormonal Spots
Melasma produces symmetrical brown patches, most often on the cheeks, forehead, nose, or upper lip. The color is typically an even brown, and the patches tend to appear on both sides of the face in a mirror-image pattern. It’s strongly linked to estrogen and progesterone, which is why it’s common during pregnancy (sometimes called “the mask of pregnancy”), in women taking birth control pills, and in those using hormone replacement therapy during menopause.
Sun exposure makes melasma worse, and in many cases it’s the combination of hormonal changes plus UV light that triggers it. Melasma can fade on its own after pregnancy or after stopping hormonal medications, but it often lingers and can be stubborn to treat. It’s not dangerous, but it tends to recur with sun exposure even after it clears.
Post-Inflammatory Hyperpigmentation
If you’ve ever had a dark mark linger for weeks or months after a pimple healed, that’s post-inflammatory hyperpigmentation (PIH). Any skin inflammation or injury can trigger it: acne, eczema, psoriasis, bug bites, burns, cuts, or even aggressive skin treatments like chemical peels or laser procedures. The inflammation causes melanocytes in the affected area to produce excess pigment, leaving behind a flat brown or dark patch after the original problem resolves.
PIH is significantly more common and more severe in people with darker skin tones. Up to 65% of people with darker skin who have acne develop noticeable dark spots afterward. The most frequent causes in darker-skinned individuals are acne, eczema, and bacterial skin infections. PIH is harmless, but the spots can take months to fade on their own, and picking at or re-irritating the area makes them darker and longer-lasting.
When a Brown Spot Could Be Skin Cancer
Most brown spots are benign, but melanoma, the most dangerous form of skin cancer, can look like a new or changing brown spot. The National Cancer Institute uses the ABCDE rule to describe warning signs:
- Asymmetry: one half of the spot doesn’t match the other half in shape
- Border: the edges are ragged, notched, or blurred, or pigment seems to spread into surrounding skin
- Color: the spot has uneven coloring, with mixtures of brown, black, tan, white, red, pink, or blue
- Diameter: the spot is larger than 6 millimeters across (about the size of a pencil eraser), though melanomas can be smaller
- Evolving: the spot has changed in size, shape, or color over the past few weeks or months
Any brown spot that checks one or more of these boxes warrants professional evaluation. The same goes for a spot that bleeds, itches persistently, or is an open sore that won’t heal. Melanoma is highly treatable when caught early, so changes in an existing mole or the sudden appearance of an unusual new spot shouldn’t be ignored.
Treatment Options for Harmless Spots
Benign brown spots don’t require treatment, but many people want them gone for cosmetic reasons. The options depend on the type and depth of pigmentation.
Topical products containing ingredients that slow melanin production (like hydroquinone, vitamin C, azelaic acid, or retinoids) can gradually lighten sun spots, melasma, and PIH over several weeks to months. Consistent sunscreen use is essential alongside any treatment, since UV exposure will darken existing spots and create new ones.
For faster or more dramatic results, professional procedures are an option. Laser treatment is considered the gold standard for removing pigmented spots. Newer picosecond lasers break up pigment with rapid pulses that cause less heat damage to surrounding skin than older technology. In studies comparing the two approaches, picosecond lasers achieved better clearance in fewer sessions (averaging about 4 sessions versus 5 or more with older lasers), with less pain and fewer side effects like rebound darkening. Chemical peels and cryotherapy (freezing) are other in-office options, though both carry a risk of triggering post-inflammatory hyperpigmentation, particularly in darker skin tones.
For melasma specifically, treatment is notoriously tricky because the hormonal component means spots frequently return. A combination approach using topical lightening agents plus strict sun protection tends to work better than any single treatment. Aggressive laser treatments can sometimes worsen melasma, so a conservative, gradual approach is typically recommended.
Preventing New Brown Spots
Since UV exposure is the single biggest driver of brown spots, daily sunscreen with SPF 30 or higher on exposed skin is the most effective prevention strategy. This applies year-round, not just during summer. UV radiation penetrates clouds and reflects off surfaces like water and concrete even on overcast days.
For people prone to PIH, treating the underlying skin condition (acne, eczema, or whatever is causing inflammation) is the best way to prevent new dark marks. Avoiding picking at blemishes or irritated skin also reduces the risk. And for those with melasma, minimizing direct sun exposure and wearing a wide-brimmed hat alongside sunscreen can help keep cleared patches from returning.