Brown spots on your skin are almost always caused by your body producing extra melanin, the pigment that gives skin its color, in a concentrated area. The three most common triggers are sun exposure, hormonal changes, and inflammation from things like acne or skin injuries. Most brown spots are harmless, but some visual features can signal something more serious.
Sun Damage Is the Most Common Cause
Ultraviolet light is the single biggest driver of brown spots. When UV rays hit your skin, they trigger a chain reaction: your skin cells release stress signals that tell pigment-producing cells to ramp up melanin output. Over time, this extra pigment clusters into visible spots. A single bad sunburn can do it, but the more typical pattern is years of cumulative exposure creating spots that seem to appear suddenly in your 30s, 40s, or beyond.
These sun-related spots go by several names: age spots, liver spots, or solar lentigines. They’re flat, tan to dark brown, and tend to show up on areas that get the most sun, like your face, hands, forearms, and shoulders. What makes them persist is a self-reinforcing loop between your pigment cells, the surrounding skin cells, and the connective tissue underneath. Once that loop is established, the spots don’t fade on their own the way a tan does.
As you age, the pigment-producing cells you have left actually grow larger and become more specialized, which is why spots tend to multiply and darken after 40 even if your sun habits haven’t changed.
Hormonal Changes and Melasma
If your brown spots appear as larger, symmetrical patches on your cheeks, forehead, upper lip, or chin, you may be dealing with melasma. This condition is driven by a combination of hormones and sun exposure, and it’s far more common in women. Estrogen increases the expression of enzymes that produce melanin, so melasma frequently shows up during pregnancy, while taking birth control pills, or during hormone replacement therapy.
Melasma isn’t just a surface-level pigment issue. It involves changes across multiple layers of skin, from the outermost layer down into the upper dermis. That’s part of what makes it stubborn to treat and prone to recurring. UV exposure alone can reactivate it even after it fades, because the underlying cellular changes persist. People with naturally darker skin tones are more susceptible, though melasma can affect anyone.
Spots Left Behind by Inflammation
Brown or dark marks that appear after acne, eczema, a burn, a cut, or even an aggressive skin treatment are called post-inflammatory hyperpigmentation. The mechanism is straightforward: inflammation sends chemical signals (prostaglandins, cytokines, reactive oxygen species) that stimulate your pigment cells to overproduce melanin. That excess pigment gets deposited into the surrounding skin cells and sometimes leaks into deeper layers.
How long these spots last depends on where the pigment ended up. If it stayed in the outer layer of skin, you can expect significant improvement within 6 to 12 months. If pigment dropped into the deeper dermal layer, fading is much slower and the marks can sometimes be permanent without treatment. You can often tell the difference by color: epidermal spots tend to look brown, while deeper ones look grayish or blue-brown.
Picking at or squeezing acne makes this worse. Inflamed breakouts that get manipulated produce more pigment and push it deeper into the skin.
How Skin Tone Affects Your Risk
People with medium to dark skin tones are significantly more prone to hyperpigmentation, particularly post-inflammatory spots and melasma. This is because darker skin has higher baseline pigment cell activity. When those cells get irritated or stimulated, they respond more aggressively with melanin production. The melanin they produce is also distributed more widely across the skin’s surface, making discoloration more visible and longer-lasting.
There’s an important misconception worth clearing up: darker skin does offer more natural UV protection due to higher levels of a protective type of melanin called eumelanin. But this protection is incomplete. People with dark skin can still get sunburned, still develop sun-related brown spots, and still develop melanoma. In fact, melanoma in darker-skinned individuals is often diagnosed at a later stage precisely because it can be mistaken for harmless hyperpigmentation.
Medications That Cause Brown Spots
Several categories of medication can trigger or worsen hyperpigmentation. The most common culprits include certain antibiotics, birth control pills, antimalarial drugs, and some antidepressants. The spots can appear anywhere on the body and sometimes develop in patterns distinct from sun-related spots, like appearing on the lower legs or in patches on the torso. If you’ve noticed new spots after starting a medication, that connection is worth raising with your prescriber.
When a Brown Spot Could Be Melanoma
The vast majority of brown spots are benign, but melanoma, the most dangerous form of skin cancer, also starts as a pigmented spot. About 112,000 new cases of melanoma are expected in the U.S. in 2026, and incidence has been rising roughly 1.1% per year over the past decade. Catching it early makes an enormous difference in outcomes.
The standard screening tool is the ABCDE checklist, developed by the National Cancer Institute:
- Asymmetry: one half of the spot doesn’t match the other
- Border irregularity: edges are ragged, notched, or blurred, with pigment that seems to spread into surrounding skin
- Color variation: multiple shades of brown, black, or tan within the same spot, or areas of white, gray, red, pink, or blue
- Diameter: larger than 6 millimeters (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 single one of these features is worth getting checked. A spot that’s changing is the most important signal, even if it doesn’t meet any of the other criteria.
Treatment Options for Benign Brown Spots
For sun spots, melasma, and post-inflammatory hyperpigmentation, treatment options range from topical products to professional procedures. The right approach depends on how deep the pigment sits, your skin tone, and the underlying cause.
Topical Treatments
Over-the-counter products containing ingredients that slow melanin production (like vitamin C, niacinamide, azelaic acid, or alpha hydroxy acids) can gradually fade superficial spots over weeks to months. Prescription-strength options work faster but carry more risk of irritation, which can paradoxically cause new dark spots, especially in darker skin tones. Daily broad-spectrum sunscreen is non-negotiable during any treatment. Without it, UV exposure will reactivate pigment production and undo your progress.
Laser and Light Treatments
For spots that don’t respond to topical treatment, laser therapy is considered the gold standard. Q-switched lasers deliver short, intense pulses of light that break apart pigment clusters. Different wavelengths target different depths: longer wavelengths penetrate deeper and are generally safer for darker skin, while shorter wavelengths work well on superficial spots but carry a higher risk of triggering new hyperpigmentation.
Newer picosecond lasers use even shorter pulses and can achieve clearance in fewer sessions. In one study of deep pigmented spots, over 96% of patients achieved near-complete clearance in an average of about four sessions. For post-inflammatory hyperpigmentation, results are more modest, with studies showing around 43% average improvement. Intense pulsed light (IPL) devices are sometimes used for superficial spots but are not effective for deeper pigmentation on their own.
If you have darker skin, laser treatment requires extra caution. The same melanin that makes your skin tone darker can absorb laser energy in unintended ways, potentially causing burns or new dark spots. Longer-wavelength lasers at lower energy settings are typically the safest choice.
Preventing New Spots
Since UV exposure is involved in nearly every type of brown spot, consistent sun protection is the single most effective preventive measure. That means broad-spectrum sunscreen daily (even on cloudy days, even in winter), reapplied every two hours during prolonged exposure. Hats and sun-protective clothing add another layer of defense, particularly for the face and hands where spots are most visible. If you’re prone to melasma, even brief unprotected sun exposure can trigger a recurrence after months of successful treatment.
For post-inflammatory spots, the best prevention is gentle management of the underlying skin condition. Avoid picking at acne, use mild products on inflamed skin, and apply sunscreen to any area that’s healing from a wound or breakout. Pigment cells are most reactive when the skin around them is inflamed, so keeping irritation low keeps pigment production in check.