Skin Cancer Screening

Early Detection for Skin Cancer

Most melanomas that appear in the skin can be seen by the naked eye. There is usually a fairly lengthy period when the tumor expands beneath the top layer of skin but doesn’t go any deeper. This allows time for screening, early detection, treatment, and a full recovery if the tumor is discovered before it spreads.

Check Your Body

The best means of finding early warning signs of skin cancer is an examination of the skin. Give yourself a good head-to-toe skin examination once a month. When you check your own body, get to know your mole patterns, freckles, and other markings on your skin and note them on a paper body chart. This way, you will be able to notice changes over time. Some parts of our body are difficult to see, like our lower back, back of our thighs, and our scalp. Ask your spouse, partner, or a good friend to help you.

Most of us have some brownish spots on our skin, freckles, birthmarks, and moles. Most of these spots are normal, but some may be precancerous or skin cancer. The Signs and Symptoms page in our Skin Cancer section covers each major skin cancer, where it is usually found, who is most likely to get it, and what it looks like.

Follow the “ABCD” Guide

Here’s what to look for during your monthly self exams. Common moles and melanomas do not look alike.

A = Asymmetry
asymetry image

Common moles are symmetrical. This means that if you draw a line down the center of a mole, the two halves will look the same. Early melanomas are asymmetrical (not symmetrical). 

B = Border
border image

Early melanomas often have uneven borders. They may even have scalloped or notched edges.


C = Color
color image

Common moles are usually a single shade of brown or black. Early melanomas are often varied shades of brown, tan, or black. As they progress, red, white, and blue may appear.


D = Diameter
diameter image

The diameter is the outside circle of the mole. The diameter of a melanoma is usually larger than a mole’s, though they can be smaller. Early melanomas generally grow to at least the size of a pencil eraser (about a ¼-inch diameter).

Other Changes to Look For

If any of these changes or symptoms appears, make an appointment with your doctor immediately. A dermatologist specially trained in skin cancer should be able to recognize a melanoma at its earliest stage. Other changes in your moles that you should be aware of include the following:

  • Size - A mole is suddenly bigger or continues to get bigger.
  • Spreading color - Melanomas can be a variety of colors and the color may spread from the edge of the mole into the surrounding tissue.
  • Elevation - A flat or slightly raised mole grows higher very quickly.
  • Surrounding skin - The skin around a mole becomes red or develops colored blemishes or swelling.
  • Surface - Mole surface changes from smooth to one with scaliness, erosion, and oozing. When a mole becomes crusty, ulcerated, or bleeds it is a sign of advanced disease.
  • Sensation - Itching is the most common early symptom. Skin cancers are usually painless, but there can be tenderness and pain.  

The American Cancer Society recommends that if you are between ages 20 and 39, you should have a skin exam by your personal doctor or a dermatologist every three years, and once a year from age 40 on. If your doctor finds something of concern, he or she will order diagnostic tests to rule out, or identify skin cancer.

Cancer screening involves examinations and tests to catch cancer in its earliest stages of development even though you have no symptoms. Don’t be alarmed if your doctor suggests skin cancer screening. This does not necessarily mean you have it. But catching skin cancer early is crucial to increasing the positive results of treatment.

Images courtesy of the Melanoma Research Foundation.