The appearance of melanoma varies, but most cases show one or more warning signs that differ from normal moles

Melanoma often looks like a mole, but it grows, changes shape, or has colors that a normal mole does not. The most common warning sign is a spot on your skin that is asymmetrical—one half does not match the other half. The border may be ragged or blurry instead of clean and round. The color is usually uneven, with brown, black, tan, or even red, white, or blue mixed together in the same spot.

Size matters too. Most melanomas are larger than a pencil eraser (about 6 millimeters across) by the time they are found. If you have a mole that is growing, changing color, or itching, or if it bleeds or oozes without injury, those are signs to have it checked by a doctor. Not every changing mole is melanoma, but a doctor can tell the difference by looking at it closely or taking a sample.

Key Takeaways

  • Melanoma often appears asymmetrical, with one half looking different from the other half.
  • The border of a melanoma is usually irregular, blurry, or jagged rather than smooth and round.
  • Color variation within a single spot—mixing brown, black, tan, red, white, or blue—is a common warning sign.
  • Any mole larger than a pencil eraser, or any spot that itches, bleeds, or changes over weeks or months, should be shown to a doctor.

The ABCDE rule: How doctors describe melanoma warning signs

Doctors use the ABCDE rule to help people recognize melanoma. A is for asymmetry—if you draw a line through the middle of the spot, the two halves should not look the same. B is for border—the edge should be smooth and even, not scalloped, notched, or blurry. C is for color—normal moles are usually one shade of brown, but melanoma often has multiple colors in the same spot.

D is for diameter—spots larger than 6 millimeters (about the size of a pencil eraser) are more concerning, though melanoma can be smaller. E is for evolving, which means changing. If a mole has grown, changed color, changed shape, started itching, or begun to bleed or ooze over weeks or months, that change is a reason to see a doctor. The ABCDE rule is not a diagnosis—it is a way to notice which spots deserve a closer look.

Where melanoma appears on the body

Melanoma can appear anywhere on the skin, but it shows up most often on areas that get sun exposure: the back, chest, legs, and face. In men, melanoma is common on the back and chest. In women, it is common on the legs and back. However, melanoma can also grow on skin that does not get much sun, including the soles of the feet, palms, under the nails, or even inside the mouth or eye.

If you have many moles, pay attention to any that look different from the others—the "ugly duckling" sign. A spot that stands out as different in color, size, or shape compared to your other moles is worth showing to a doctor, even if it does not fit all the ABCDE criteria perfectly.

What melanoma feels like and other physical changes

Beyond appearance, melanoma can cause physical sensations or changes you can feel. Itching is common and often one of the first signs. The spot may feel tender or sore even without being touched. Some people notice the skin around the spot becomes raised or bumpy. Bleeding or oozing without any injury—just from normal contact or scratching—is another warning sign.

A spot that was flat and suddenly becomes raised, or one that develops a hard or crusty texture, should be checked. These changes happen over weeks or months, not overnight. If you notice any of these signs on a mole or spot you have had for years, that change is what matters most—not whether the spot looked concerning when you first noticed it.

Types of melanoma and how they look different

Superficial spreading melanoma is the most common type and usually appears as a flat or slightly raised spot with irregular borders and mixed colors. It grows outward across the skin before growing deeper. Nodular melanoma looks like a raised bump or nodule, often dark brown or black, and can grow downward into the skin quickly. It may bleed or ooze.

Lentigo maligna melanoma usually appears on the face or neck as a large, flat patch with irregular borders and uneven color. It grows slowly at first. Acral lentiginous melanoma appears on the palms, soles, or under the nails and is less common but more aggressive. On the nail, it looks like a dark streak or band. These types have different growth patterns, but all share the basic warning signs: asymmetry, irregular borders, color variation, and change over time.

When to see a doctor about a spot on your skin

See a doctor if you have a mole or spot that is asymmetrical, has an irregular border, shows multiple colors, is larger than a pencil eraser, or has changed in the past few months. You do not need to wait for all the ABCDE signs to be present—even one or two are reason enough for a professional look. A dermatologist (a doctor who specializes in skin) can examine the spot closely and decide whether it needs to be removed and tested.

If you have a family history of melanoma, have had melanoma before, or have many moles, your doctor may recommend regular skin checks. During a check, the doctor looks at all your moles and takes photos to track changes over time. If a spot looks suspicious, the doctor will remove a small sample (a biopsy) and send it to a lab to test for cancer cells. This is the only way to know for certain whether a spot is melanoma.

Frequently Asked Questions

Can melanoma look like a normal mole?

Yes. Early melanoma can look very similar to a normal mole, which is why change over time is so important. If a mole you have had for years suddenly grows, changes color, or becomes itchy, that change is the warning sign, not necessarily how it looks at that moment. A doctor can tell the difference by examining it closely.

Is every dark spot on my skin melanoma?

No. Most dark spots and moles are benign (not cancer). Age spots, freckles, and common moles are very common and not dangerous. The difference is usually in the shape, border, color variation, and whether the spot is changing. A doctor can examine any spot that concerns you and let you know whether it needs further testing.

What if I find a spot that looks like melanoma?

Contact your primary care doctor or a dermatologist and describe what you see. You can take a photo to show the doctor, but do not wait for an appointment to pass—call soon. Most spots that look suspicious turn out to be benign, but the sooner a doctor sees it, the sooner you will know.

Can melanoma be hidden under the skin where I cannot see it?

Melanoma starts on the surface of the skin, so you should be able to see it. However, it can grow downward into deeper layers of skin over time. This is why catching it early—when it is still flat or only slightly raised—makes a difference in treatment. Regular skin checks help catch melanoma before it grows deeper.

Do I need to check my skin myself, or should I only see a doctor?

Both help. Checking your own skin once a month—looking at moles on your back, between your toes, and other spots you do not see often—helps you notice changes early. A dermatologist can spot things you might miss and can examine spots with special tools. If you have many moles or a family history of melanoma, regular doctor visits are especially important.