Brown spots on the skin are almost always caused by extra melanin, the pigment that gives skin its color. The most common culprits are sun exposure, hormonal changes, aging, and inflammation from past skin injuries. Most brown spots are harmless, but their appearance, location, and behavior can tell you a lot about what’s causing them and whether they need attention.
Sun Spots (Solar Lentigines)
These are the spots most people mean when they say “age spots” or “liver spots,” though they have nothing to do with your liver. Solar lentigines are flat, tan to dark brown marks that develop on skin that’s had years of sun exposure or past sunburns. You’ll typically find them on the face, forearms, chest, and tops of the hands. They’re larger than freckles, often the size of a pencil eraser or bigger, and they don’t fade in winter the way freckles do.
Sun spots are permanent deposits of excess pigment. Unlike a tan, which fades as skin cells turn over, these marks reflect lasting changes in how pigment-producing cells behave in that patch of skin. They’re harmless, but their presence is a sign of significant cumulative UV damage in that area.
Seborrheic Keratoses
If your brown spot looks like it’s been glued onto your skin rather than growing from within it, you’re likely looking at a seborrheic keratosis. These growths are extremely common after age 50 and can appear on almost any part of the body except the palms and soles. They range from light tan to nearly black.
The texture is the giveaway. Seborrheic keratoses are covered in keratin, the same protein that makes up your fingernails. This gives them a waxy, scaly, or rough surface. Up close, some look like they contain tiny bubbles or cysts. Others resemble warts or even have ridged, brain-like folds. You can always feel them with your finger, even when they appear relatively flat. They’re completely benign and don’t become cancerous, though new ones can keep appearing over time.
Melasma
Melasma looks different from other brown spots. Instead of distinct circles or ovals, it forms larger, irregular patches with blurred edges, most often across the cheeks, forehead, upper lip, and bridge of the nose. It’s most common in women in their 20s and 30s, and the patches are usually symmetrical, appearing on both sides of the face.
Two forces drive melasma: radiation and hormones. UV light, visible light, and even infrared heat from the sun all stimulate pigment-producing cells to go into overdrive. At the same time, estrogen and progesterone amplify this response, which is why melasma frequently appears during pregnancy (sometimes called “the mask of pregnancy”), while taking hormonal birth control, or in anyone with elevated estrogen receptor activity in the skin. The combination of sun and hormones makes melasma particularly stubborn. It can fade on its own after pregnancy or after stopping hormonal contraception, but it often returns with sun exposure.
Marks Left by Skin Inflammation
If a brown spot sits exactly where you had a pimple, a burn, an insect bite, a rash, or any kind of skin injury, it’s likely post-inflammatory hyperpigmentation (PIH). This happens when inflammation triggers your pigment cells to dump extra melanin into the surrounding skin as it heals. The result is a flat, discolored mark that lingers long after the original injury is gone.
PIH can happen to anyone, but it’s more common and more noticeable in people with medium to dark skin tones. The color gives a clue about depth: light to dark brown marks mean the extra pigment is in the upper layers of skin and will generally fade within months. Blue-gray marks suggest pigment has dropped into deeper layers, which can take a year or longer to resolve. Picking at acne, scrubbing inflamed skin, or skipping sun protection on healing areas all make PIH worse.
When a Brown Spot Could Be Skin Cancer
The vast majority of brown spots are benign, but melanoma can disguise itself as an ordinary-looking mark. Dermatologists use the ABCDE framework to flag spots that need closer evaluation:
- Asymmetry: one half of the spot doesn’t match the other half in shape.
- Border: the edges are ragged, notched, or blurred, or pigment appears to spread into the surrounding skin.
- Color: the spot contains multiple shades of brown, black, or tan, or has areas of white, gray, red, pink, or blue.
- Diameter: the spot is larger than about 6 millimeters (roughly 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 spot that meets one or more of these criteria deserves a professional look. A dermatologist can examine it with a magnifying instrument called a dermatoscope and, if anything looks suspicious, take a small tissue sample to check under a microscope. Biopsies are also recommended for any new or changing mole, an area of rough or scaly skin that won’t resolve, or an open sore that doesn’t heal.
How to Treat Existing Brown Spots
Treatment depends entirely on the type of spot. Seborrheic keratoses don’t need treatment unless they’re irritating or cosmetically bothersome, in which case a dermatologist can freeze or scrape them off in a quick office visit. PIH often resolves on its own with time and consistent sun protection. Melasma and sun spots are more persistent but respond to several approaches.
For melasma and sun spots, prescription creams containing hydroquinone (typically at 2% or 4% strength) remain the most widely used option. Hydroquinone works by slowing the production of melanin in the treated area. It’s currently available only by prescription in the United States after the FDA pulled over-the-counter formulations from the market in 2020. The only FDA-approved combination product pairs hydroquinone with a retinoid and a mild steroid, specifically for moderate to severe melasma on the face. Retinoids on their own can also help by speeding up skin cell turnover, gradually pushing pigmented cells to the surface where they shed.
Over-the-counter options include products with vitamin C, azelaic acid, niacinamide, or alpha hydroxy acids. These work more slowly than prescription treatments but can make a visible difference over several months, especially for mild discoloration.
Laser and Light Treatments
For spots that don’t respond well to topical products, in-office procedures can help. Non-ablative fractional lasers work by creating microscopic zones of controlled injury in the pigmented area, prompting the body to replace those cells with fresh, evenly pigmented skin. This type of laser is particularly useful for melasma because it doesn’t generate significant heat. That distinction matters: treatments that heat the skin, like intense pulsed light (IPL), can actually make melasma worse. For sun spots and other non-hormonal pigmentation, combining a fractional laser with broadband light treatments can produce dramatic results.
Most laser treatments require two to four sessions spaced a few weeks apart, with mild redness and flaking for a few days after each session.
Preventing New Spots and Darkening
Every type of brown spot gets darker with sun exposure. A broad-spectrum sunscreen with at least SPF 30 is the single most effective tool for preventing new spots and keeping existing ones from worsening. “Broad-spectrum” means it blocks both UVA rays (which penetrate deep and trigger pigmentation) and UVB rays (which cause sunburn).
For melasma especially, protection goes beyond UV. Visible light and heat can also stimulate pigment production, which means tinted sunscreens containing iron oxide offer an extra layer of defense that clear sunscreens don’t. Reapplying every two hours during sun exposure, wearing a wide-brimmed hat, and seeking shade during peak hours all compound the benefit. If you’re treating brown spots with any topical product or laser, skipping sun protection essentially undoes the work.