ABCDEs of Skin Cancer: How to Spot Dangerous Moles Early

Cancer
Originally Published:
May 27, 2025
Updated:
May 27, 2025
Read Time:
3 min
Author:
BMG Staff
ABCDEs of Skin Cancer: How to Spot Dangerous Moles Early

Skin cancer is the most common form of cancer in the United States, but when caught early, it’s also one of the most treatable. One of the best ways to spot skin cancer early—especially melanoma—is by learning the ABCDE rule, a simple guide to identifying concerning moles or skin spots.

At BASS Cancer Center, we’re here to help you understand these signs and take action if something looks suspicious.

What Are the ABCDEs of Skin Cancer?

Use this easy guide when performing regular self-exams or evaluating a mole:

A = Asymmetry

Healthy moles are usually symmetrical.
Warning sign: One half of the mole doesn’t match the other.

B = Border

Benign moles have smooth, even borders.
Warning sign: Irregular, scalloped, or jagged edges.

C = Color

A single shade (usually brown) is typical.
Warning sign: Multiple colors like black, red, blue, white, or uneven coloring.

D = Diameter

Most harmless moles are small.
Warning sign: Spot is larger than 6mm (about the size of a pencil eraser)—though melanomas can be smaller.

E = Evolving

This is the most important sign.
Warning sign: The mole is changing in size, shape, color, elevation, or causing itching, bleeding, or crusting.

If a mole has any of these features—or just looks or feels “off”—it’s worth getting checked by a specialist.

When to Do a Skin Self-Exam

Check your skin once a month in a well-lit room using a full-length mirror and a hand mirror. Don’t forget:

  • Your scalp
  • Back and shoulders
  • Behind ears
  • Between fingers and toes

Take photos if needed to monitor changes over time.

When to Call a Doctor

If you notice any of the ABCDE signs or have a spot that’s changing, bleeding, or painful, reach out to your Primary Care Provider. At BASS, we can:

  • Evaluate suspicious lesions
  • Refer you to cancer or dermatology specialists
  • Perform biopsies or imaging when needed
  • Offer personalized treatment through our BASS Cancer Center

Protect Your Skin Year-Round

Early detection can be lifesaving. Use sunscreen, avoid tanning beds, and keep an eye on your skin. And during Skin Cancer Awareness Month—or anytime—you can count on BASS Medical Group for expert care.

Visit the BASS Cancer Center
Schedule a skin evaluation or primary care checkup

Medical Disclaimer: The information provided in this blog is for educational and informational purposes only and is not intended as medical advice, diagnosis, or treatment. BASS Medical Group does not endorse any specific tests, treatments, procedures, or opinions referenced in this content. Individual results may vary. Always consult with your physician or a qualified healthcare provider regarding any medical concerns or before making changes to your health regimen.