Yale Dermatologic Surgery
Temple Medical Center
40 Temple St
5th Floor, Ste 5A
New Haven, CT 06510
203.785.3466
Toll Free: 1.866.316.7546
The ABCD method of checking for melanoma has been widely touted for public health purposes. The problem is that some of the changes described in it do not occur early, and we want to catch melanoma early. Nevertheless, we recommend you learn these ABCDs and know them cold. In addition, we include ways to become suspicious of growths even earlier, when the cure rate is potentially higher.
A Asymmetry If you fold the mole over in your mind's eye, the halves do not match.
B Border irregularity The edges of the mole are ragged, notched or blurred, not smooth like normal moles.
C Color The coloration of the mole is irregular. There are shades of tan, brown, and black. Even red, white, and blue can add to the mottled appearance.
D Diameter Any diameter greater than a pencil eraser (about 5-6 millimeters) should raise suspicion. In addition to these broad guidelines, two more, a "C and an "S": Concern. Even if you don't know why, if you sense there is something of concern about a mole, insist your doctor biopsy it. Suspicion. This is one time when it's okay to be suspicious. Doctors call it having a "high index of suspicion." We call it being vigilant. But whatever you call it, when it comes to melanoma, the best rule is "When in doubt, check it out."