Most melanomas show up as a new or changing spot on the skin that looks different from your other moles. The classic warning signs follow a pattern you can learn to recognize at home, but some melanomas break the rules entirely, appearing as pink bumps, dark streaks under a nail, or spots in places you’d never think to check. Catching it early matters enormously: when melanoma is found before it spreads, the five-year survival rate is about 98%. Once it reaches distant organs, that number drops to roughly 16%.
The ABCDE Rule for Checking Moles
The most widely used framework for spotting melanoma at home is the ABCDE rule, developed by the National Cancer Institute. Each letter flags a specific visual feature:
- Asymmetry. One half of the mole doesn’t match the other. Normal moles tend to be roughly symmetrical.
- Border. The edges are ragged, notched, or blurred rather than smooth. Pigment may seem to bleed into the surrounding skin.
- Color. Instead of one uniform shade of brown, you see a mix of brown, tan, black, or even patches of white, gray, red, pink, or blue within the same spot.
- Diameter. The spot is larger than about 6 millimeters, roughly the size of a pencil eraser. Melanomas can be smaller than this, but most exceed it.
- Evolving. The mole has changed in size, shape, or color over the past few weeks or months. Any noticeable change in a mole deserves attention.
A spot doesn’t need to hit all five criteria to be suspicious. Even one or two of these features, especially evolution, is enough reason to have it evaluated.
The “Ugly Duckling” Sign
Sometimes the simplest approach is the most useful. The ugly duckling sign means one mole stands out from the rest. Most people’s moles share a general “family resemblance” in size, shape, and color. If one spot looks noticeably different from all the others on your body, that outlier deserves a closer look, even if it doesn’t clearly meet the ABCDE criteria. This is especially helpful for people with many moles who find it hard to evaluate each one individually.
Melanomas That Don’t Look Like Melanomas
Not every melanoma follows the textbook pattern of a dark, irregularly shaped mole. Two types in particular are easy to miss.
Nodular Melanoma
Nodular melanoma is one of the more aggressive forms, and it often bypasses the ABCDE features because it grows vertically into the skin rather than spreading outward. Instead of a flat, multicolored patch, it typically appears as a raised bump that feels firm to the touch and grows steadily over weeks or months. Dermatologists use a separate set of criteria called the EFG rule: Elevated above the skin surface, Firm when pressed, and Growing progressively. If you notice a new bump on your skin that’s solid and getting bigger, don’t wait for it to develop irregular borders or mixed colors.
Amelanotic Melanoma
About 5% of melanomas produce little or no pigment, making them pink, red, or skin-colored rather than dark. These amelanotic melanomas are frequently mistaken for pimples, bug bites, or other harmless skin conditions, which means they’re often diagnosed at a later stage. If you have a pink or reddish spot that won’t heal, keeps coming back, or slowly enlarges, it’s worth having a dermatologist look at it.
Melanoma on Palms, Soles, and Under Nails
Acral lentiginous melanoma develops on the palms of the hands, soles of the feet, and under fingernails or toenails. It occurs equally across all races and skin tones, but it accounts for the majority of melanoma cases in people of color, partly because the more common sun-related types are less frequent in darker skin.
On the palms or soles, the first sign is usually a black or brown discoloration that looks like a bruise or stain but doesn’t fade and gradually grows. Under the nails, the subtype called subungual melanoma appears as dark vertical streaks or discolorations running along the nail bed. Over time, it can cause the nail to crack or break. It’s commonly mistaken for dried blood under the nail or a fungal infection. A key difference: a bruise under the nail grows out with the nail over weeks, while a melanoma streak stays in place or widens.
Hidden Locations You Might Not Check
Melanoma can develop in places that never see the sun. Mucosal melanoma forms on the moist tissue lining the inside of the body, and the symptoms depend entirely on where it occurs. In the mouth, you might notice a persistent sore, a growing lump on the tongue, unexplained bleeding, or pain. In the nasal passages, repeated nosebleeds from one side, a constant feeling of obstruction, or facial pain can signal a problem. In the anal or rectal area, symptoms include pain, a lump, bleeding, or persistent itching. Vaginal or vulvar melanoma can cause bleeding between periods or after menopause, unusual discharge, or a new growth.
Because these areas are hidden, mucosal melanomas tend to be found late. They’re rare, but they’re worth knowing about, especially if you develop any of the symptoms above without an obvious explanation.
During self-exams, also check areas like the scalp (use a blow dryer to part your hair), between the toes, behind the ears, and on the back of the legs. Having a partner check your back and other hard-to-see areas makes a real difference.
What Happens When You See a Dermatologist
A dermatologist’s first tool beyond the naked eye is dermoscopy, a handheld magnifying device with a built-in light that reveals structures in the skin invisible to the unaided eye. Research published in The Lancet Oncology found that dermoscopy improved diagnostic accuracy for melanoma by 49% compared to visual inspection alone. There’s an important caveat: that improvement depends on the examiner’s experience. Dermoscopy in the hands of someone without specialized training performed no better than looking at the spot without any device.
If a spot looks suspicious under dermoscopy, the next step is a biopsy, where a small sample of skin (or the entire spot) is removed and examined under a microscope. This is the only way to confirm melanoma with certainty. The procedure is typically done in the office under local numbing and takes just a few minutes.
How Depth Determines Your Outlook
If the biopsy confirms melanoma, the single most important measurement is called the Breslow depth: how far the melanoma extends into the skin, measured in millimeters from the surface. A thinner melanoma has a dramatically better prognosis than a thicker one. This measurement drives all subsequent decisions about treatment and further testing.
About 83% of melanomas are diagnosed while still localized to the skin, and the five-year survival rate at that stage is 97.6%. When melanoma has spread to nearby lymph nodes (regional spread), survival drops to about 60%. Distant spread carries a five-year survival rate of roughly 16%. The overall five-year survival rate across all stages is 90.5%, largely because most cases are caught early.
These numbers underscore why self-checks and timely evaluation matter so much. A melanoma caught when it’s thin and confined to the upper layers of skin is almost always curable. The same cancer caught months later, after it has grown deeper, becomes a far more serious problem.
How Often to Check Your Skin
A thorough self-exam once a month is a reasonable habit. Use a full-length mirror and a hand mirror to see your back, scalp, and other hard-to-view areas. Take photos of moles that look unusual so you can track changes over time. You’re looking for anything new, anything changing, and anything that stands out from the rest of your moles.
If you have a large number of moles, a personal or family history of melanoma, or a history of severe sunburns, annual skin checks with a dermatologist give you an additional layer of detection that self-exams alone can’t provide.