Most spots that appear on your skin are harmless. The vast majority turn out to be common growths like age spots, cherry angiomas, or seborrheic keratoses that need no treatment at all. But because a small number of skin spots can signal something more serious, knowing what to look for makes a real difference. Here’s how to start narrowing down what you’re seeing.
The Most Common Harmless Spots
If you’re an adult noticing a new spot, there’s a good chance it falls into one of three categories.
Age spots (solar lentigines) are flat, tan to brown-black marks caused by years of sun exposure. They have sharp, well-defined borders and uniform color. They’re most common on the face, hands, shoulders, and forearms, and they become more prevalent as you get older. These are purely cosmetic and don’t require treatment.
Seborrheic keratoses are among the most frequently googled skin spots because they can look alarming. They appear as waxy, dull, or warty-textured plaques that seem “stuck on” the skin surface. They range from yellow to brown to black and sometimes contain several colors at once. Their shape is often irregular and can change over time, which understandably worries people. Despite their rough appearance, they’re completely benign.
Cherry angiomas are small, bright red dots (or deeper purple-blue bumps) caused by clusters of blood vessels. They can appear anywhere on the body, tend to multiply with age, and are harmless. Pressing on a superficial one may briefly blanch it white.
Spots That Deserve a Closer Look
Roughly 2.2 percent of people will be diagnosed with melanoma at some point in their lifetime, and an estimated 104,960 new cases are expected in the United States in 2025 alone. Melanoma is more common in men, in people with fair complexions, and in those with significant sun or tanning bed exposure. Catching it early is critical because localized melanoma has a far better prognosis than melanoma that has spread.
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: The edges are ragged, notched, or blurred, and pigment may spread into surrounding skin.
- Color variation: Multiple shades of brown, black, or tan, sometimes with areas of white, gray, red, pink, or blue.
- Diameter: Most melanomas are larger than 6 millimeters (about the size of a pencil eraser), though they can start smaller.
- Evolving: The spot has changed in size, shape, or color over the past few weeks or months.
You don’t need all five features to be concerned. Any single one, especially a spot that is clearly evolving, is worth having a professional evaluate.
The “Ugly Duckling” Shortcut
Sometimes the fastest way to spot trouble isn’t analyzing one mole in isolation. It’s noticing which mole doesn’t look like the others. Moles on the same person tend to resemble each other in color, size, and shape. A mole that stands out as obviously different from its neighbors is called an “ugly duckling,” and research published in JAMA Dermatology found this simple approach catches melanoma with about 90 percent sensitivity overall. Even non-clinicians in the study identified ugly ducklings with 85 percent sensitivity. If one spot on your body looks nothing like the rest, that alone is a reason to get it checked.
Non-Melanoma Skin Cancers
Melanoma gets the most attention, but two other skin cancers are far more common.
Basal cell carcinoma typically shows up on sun-exposed skin as a pink bump with a pearly or waxy appearance. It often has a sunken center, tiny visible blood vessels on its surface, and a tendency to bleed easily after minor injury. It rarely spreads to other parts of the body, but it can grow into surrounding tissue if left alone, making early removal simpler and less invasive.
Squamous cell carcinoma appears as a raised, dull-red lesion with a thick, crusted, scaly surface that may look ulcerated. It favors the head, ears, hands, back of the neck, and forearms. It’s rarely fatal, but unlike basal cell, it carries a small risk of spreading if not treated promptly.
Both types share a key warning sign: a sore or bump that won’t heal. If a spot on your skin hasn’t healed after three months of normal care, or looks unusual and persists for three to six months, a biopsy is the standard next step.
Rough, Scaly Patches and Precancer
Actinic keratoses are dry, rough, sandpaper-textured patches that develop on sun-damaged skin. They’re considered precancerous because a small percentage progress to squamous cell carcinoma. Estimates of that progression rate vary widely, from less than 1 percent to 16 percent per year per lesion, with significantly higher risk (around 40 percent over five years) in people who have already had a squamous cell carcinoma. Because there’s no reliable way to predict which patches will progress, dermatologists generally treat them rather than watch and wait.
Spots on Darker Skin
Skin cancer screening guidelines are largely built around patterns seen on lighter skin, which can leave people with darker skin tones underserved. Melanoma in people of color disproportionately appears as acral lentiginous melanoma, a subtype that develops on the palms, soles of the feet, and under the nails. It accounts for only 2 to 3 percent of all melanoma cases, but it’s not related to UV exposure and arises on areas that don’t get much sun.
On the palms and soles, these lesions often appear as irregularly pigmented dark brown or black patches. Under a nail, the hallmark sign is a dark pigmented streak running the length of the nail, sometimes extending onto the surrounding skin fold and causing the nail to split. Any new dark streak under a fingernail or toenail that isn’t explained by recent injury warrants evaluation, especially if it’s widening or changing color.
What Happens at a Dermatologist Visit
A dermatologist examining a suspicious spot will typically use a dermatoscope, a handheld magnifying device with its own light source that reveals structures invisible to the naked eye. This isn’t just a fancy magnifying glass. A Cochrane review found that dermatoscopy improves melanoma detection by about 16 percentage points compared to visual inspection alone (92 percent vs. 76 percent sensitivity). It also reduces unnecessary biopsies by about 20 percentage points. In practical terms, that means fewer melanomas missed and fewer people having harmless spots cut out for no reason.
If a spot looks suspicious under dermatoscopy, the next step is a biopsy, where a small sample of tissue is removed and examined under a microscope. Most biopsies are quick office procedures done under local anesthesia, and results typically come back within one to two weeks.
How to Check Your Own Skin
A thorough self-exam means checking your entire body from head to toe, including your scalp (use a blow dryer to part your hair), between your toes, the soles of your feet, and even the inside of your mouth. Use a full-length mirror and a hand mirror for hard-to-see areas like your back and the backs of your legs. The goal isn’t to diagnose anything yourself. It’s to build a mental map of your spots so you notice when something new appears or an existing spot changes. Taking phone photos of spots you want to track gives you a reliable baseline to compare against later.
Pay particular attention to spots in sun-exposed areas if you have fair skin, and to your palms, soles, and nails if you have darker skin. A spot that itches persistently, bleeds without being scratched, or develops a crust that doesn’t go away is always worth mentioning to a doctor, regardless of what it looks like.