Seborrheic keratoses look like waxy, slightly raised growths that appear to be “stuck on” the surface of the skin, as if someone dripped candle wax onto it. They range in color from light tan to brown to black and have a rough or scaly texture. Most are round or oval, starting small and sometimes growing to several centimeters across. They’re extremely common: virtually 100% of people over 50 have at least one, and by age 75, the average person has around 69 of them.
The Classic “Pasted On” Look
The single most recognizable feature of a seborrheic keratosis is that it looks like it’s sitting on top of the skin rather than growing from within it. Dermatologists often describe them as having a “pasted on” or “stuck on” appearance. The edges are well-defined, and it can seem like you could peel the growth right off (though you shouldn’t try).
The surface texture varies. Some feel smooth and waxy, almost like a drop of dried wax. Others are rougher, with a dry, scaly, or even warty texture. If you look closely, you may notice tiny plugged pores dotting the surface, giving it a grainy or pitted appearance. Thicker growths sometimes develop a pattern of ridges and fissures that can resemble the folds on the surface of a brain.
Color Range
Seborrheic keratoses come in a wide range of colors: light tan, medium brown, dark brown, and black. A single growth can contain more than one shade. Lighter-skinned individuals tend to develop tan or brown growths, while people with darker skin tones may develop darker brown or black ones. The color is usually fairly even throughout the growth, which is one clue that helps distinguish it from melanoma.
How They Change Over Time
These growths don’t appear fully formed. They typically start as small, flat, light-brown spots with a smooth or velvety surface, often smaller than 1 centimeter. At this early stage, they can be easy to overlook or mistake for a freckle or age spot.
Over months to years, they slowly thicken and become more raised. The surface shifts from smooth to rougher and more textured, developing that characteristic waxy or warty quality. As they mature, they darken in color and take on the unmistakable “stuck on” look. New growths also tend to appear over time, which is why older adults often have dozens scattered across their body.
Where They Show Up
Seborrheic keratoses appear most often on the chest, back, shoulders, face, and scalp. They can show up on the arms and legs as well. They don’t grow on the palms of the hands or soles of the feet. You can develop a single growth or dozens, and it’s common to have them in clusters, particularly across the trunk and upper body.
How They Look on Darker Skin
In people with darker skin tones, seborrheic keratoses often appear as a specific variant called dermatosis papulosa nigra. These are small, dark brown to black, raised papules, typically 1 to 5 millimeters across. They tend to cluster symmetrically on the face, especially along the cheekbones and temples, and also appear on the neck and trunk. They’re usually painless, though they can occasionally feel dry, scaly, or mildly itchy. The actor Morgan Freeman’s prominent facial spots are a well-known example of this variant.
When They Become Irritated
Seborrheic keratoses are normally painless, but they can become irritated from friction with clothing, jewelry, or repeated rubbing. When this happens, the growth may become red, swollen, or tender. It can also bleed or develop a crust on the surface. An irritated seborrheic keratosis can look more alarming than it actually is, and the sudden change in appearance sometimes prompts concern about skin cancer. If a growth you’ve had for a while becomes inflamed, that’s worth getting checked, but friction is the most common explanation.
How to Tell Them Apart From Skin Cancer
Because seborrheic keratoses can be dark and irregularly shaped, they sometimes look similar to melanoma at first glance. A few visual differences help separate the two.
Seborrheic keratoses tend to have a consistent, even color throughout the growth. Melanomas often contain uneven mixtures of colors: brown, black, red, white, or blue within the same spot. Seborrheic keratoses have relatively smooth, well-defined borders, while melanomas tend to have ragged or irregular edges. Seborrheic keratoses look the same from one side to the other (symmetrical), while melanomas are often asymmetrical.
The most important distinction is change. Seborrheic keratoses grow slowly and stay stable once they’ve matured. A spot that is rapidly changing in size, shape, or color deserves a closer look. Dermatologists use the ABCDE framework for evaluating suspicious spots: Asymmetry, Border irregularity, Color variation, Diameter larger than 6 millimeters, and Evolving appearance.
The Sign of Leser-Trélat
In rare cases, a large number of itchy seborrheic keratoses appear suddenly over a short period. This pattern, known as the sign of Leser-Trélat, can be associated with an internal malignancy. It’s uncommon, but the sudden eruption of many new growths, especially if they’re itchy and developing rapidly, is worth bringing to a doctor’s attention promptly. Individual seborrheic keratoses that develop gradually over time are not a cancer concern.
What a Doctor Sees Up Close
If your doctor examines a growth with a dermatoscope (a handheld magnifying tool with a light), they’ll look for specific features that confirm a seborrheic keratosis. These include tiny white or yellow cyst-like dots embedded in the surface and small round openings that resemble plugged pores. Finding more than three of these small cysts in a single growth strongly suggests it’s a benign seborrheic keratosis. The blood vessels in the growth also tend to look uniform and looped, rather than irregular or branching, which would raise concern for something else. These details aren’t visible to the naked eye, but they’re what allows a dermatologist to confidently identify the growth without a biopsy in most cases.