Clinically, nevus anemicus is a circumscribed, rounded, oval or linear pale macule or patch with irregular margins that may be surrounded by satellite macules. Lesions may be single or multiple and may be located on any part of the body, but most lesions commonly are found on the upper chest. They occur more frequently in females and are usually asymptomatic. Nevus anemicus may be present at birth or appear in early childhood, although it may be easy to overlook. Nevus anemicus usually persists unchanged throughout life.
Lesions occur with increased frequency in patients with neurofibromatosis.
Areas of nevus anemicus frequently are extensive and have been observed in close association with macular telangiectatic nevi of port-wine stain type, a phenomenon attributed to somatic recombination. Nevus anemicus also has been described in patients with phakomatosis pigmentovascularis, a syndrome characterized by vascular and melanocytic nevi. With diascopy, nevus anemicus becomes indistinguishable from the blanched surrounding skin. Loss of melanin does not occur in the lesion. Wood lamp examination does not accentuate it and may make the lesion inapparent, unlike true depigmenting disorders.