Birthmark (Congenital Melanocytic Nevus):
A parent's guide for infants and babies

Congenital melanocytic nevi are brown or black, usually raised spots or patches, that are present at birth or shortly after (before 1 year). They are usually single but can be multiple and range in size greater than 1 cm to less than 20 cm (bathing suit or garment lesions cover large sections of the body). Smaller, so-called, satellite lesions are sometimes associated with large lesions.

The most common locations for these birthmarks are the buttocks, thighs, and trunk, but lesions may occur on the face and extremities, and, least commonly, on the palms, soles, and scalp.

Changes in thickness, color, and hair content occur through childhood and adolescence. In later adult years, they may actually fade in color to a lighter brown.