Signs and Symptoms of Skin Cancer

Most people are alerted to the possibility that they have skin cancer because they notice a difference in the appearance of their skin. Such an occurrence may take the form of a spot, sore, or mole with a changeable size, shape, color, or "feel." Some common presentations of early skin cancers are:

  • firm, red lump
  • small, pale, smooth, shiny or "waxy" lump
  • sore that begins oozing or bleeding
  • sore or rough red spot that becomes scaly or crusty
  • spot that becomes itchy, tender, or painful
  • spot that becomes red and/or swollen
  • mole that grows or otherwise changes its appearance

Basal and squamous cell cancers typically occur on parts of the skin that receive the most exposure to sunlight - the face, head, necks, arms, and hands (see Types of Skin Cancer). Excessive exposure to the sun can cause a condition known as actinic keratosis. This skin disorder, which primarily affects middle-aged and elderly individuals, is characterized by sharply outlined wart-like or horny growths. Such growths may appear as rough, red or brown scaly patches on exposed skin, although they may appear elsewhere. Actinic keratosis is a "precancerous" condition; that is, the cells within it are very abnormal and may become malignant (cancerous) over time.

Ordinary moles, or "nevi," typically appear as evenly colored (brown, black, tan), round "spots" on the skin. They can be present at birth, or they may appear at any time during a person's life, often after periods of sun exposure. Most are small (less than 6 millimeters in diameter), and they do not change in size or shape, although they may fade somewhat in older individuals. By contrast, melanoma - a much more serious form of skin cancer -usually begins as an abnormal mole. In order to distinguish a normal mole from a melanoma, dermatologists (specialists in skin diseases) have developed the ABCD rule.

According to this guide, the following features characterize melanoma:

  • Asymmetry—One half of the mole does not match the other half
  • Border Irregularity—Borders (edges) of the mole are jagged or notched
  • Color—There is no overall color of the mole; parts may be varying shades of black, brown, or tan, with white, red, or even blue splotches
  • Diameter—Most melanomas are wider than 6 millimeters, although some may range between 3 and 6 millimeters in size

Not all melanomas have the features defined by the ABCD rule, so it is necessary to watch for any skin symptoms that last longer than 2 weeks. Any new, colored growths or changes in existing moles or lesions should be reported to a physician, preferably a dermatologist (skin specialist), without delay. Because skin cancers rarely are painful, one should not wait to call a physician if the lesion doesn't "hurt."

Publication Review By: the Editorial Staff at

Published: 15 Aug 1999

Last Modified: 26 Feb 2015