A 7-year-old girl presented with a congenital blackish lesion over her
forehead that had developed a white halo around it during the last three
months. There was no history of white patches elsewhere over the skin.
Examination revealed an oval hairy plaque of melanocytic nevus
surrounded by a rim of depigmentation just above the left eyebrow (Fig.
1). There were no other mucocutaneous or systemic abnormalities. A
diagnosis of halo nevus was made and periodic follow-up was advised.
 |
|
Fig. 1 Halo of depigmentation around a
central melanocytic nevus.
|
Halo nevus designates the development of a halo of
hypomelanosis around a central cutaneous tumor. This tumor is usually a
benign melanocytic nevus but rarely blue nevus, neurofibroma or
malignant melanoma may show the halo phenomenon. Halo nevi presumably
result from immunologically mediated host responses to a nevus. This is
usually seen in children or young adults of either sex particularly on
the trunk, less commonly on the head and rarely on the limbs. It occurs
with increased frequency in patients with vitiligo. Normally no
treatment is required. The nevus tends to flatten and may disappear
completely. The depigmented areas often persist, but may repigment after
a variable period of time.
