Halo Nevus

A halo nevus is a mole with a white ring or “halo” around it. They are most commonly found in children and young adults of either sex. These moles are entirely benign and are of only cosmetic significance. Patients with halo nevi usually have no symptoms. Vitiligo, melanoma and atypical nevi can be seen occasionally be seen together.

Pathogenesis:
For reasons that are unknown, the body selects a particular mole or moles for destruction. This is presumably because the mole is recognized as being abnormal or foreign in some way. A circulating antibody and special white cells (T cells) attack the pigment cells in the mole. This causes the central mole to fade from dark brown to light brown to pink, and eventually to disappear completely. Some of the reaction affects the normal skin around the mole, which also has pigment cells in it, causing the white halo.

Presentation:
Halo nevi are usually single, but may be multiple. They can develop anywhere on the body, but are seen most frequently on the trunk. Clinically, they appear as one or more uniformly colored, evenly shaped, round or oval nevi centrally with even peripheral margins of hypopigmentation (color lighter than normal skin tone). The central nevus may be tan, pink, or brown. The width of the halo is variable but is generally of uniform radial distance from the central nevus. The central nevus may persist indefinitely or go away completely, in some cases with the halo remaining. The coloration of the central nevus may not change or may become irregular or pink or red. Some moles gradually disappear with complete repigmentation of the skin.

Treatment:
All persons with halo nevi should be questioned for a personal or family history of malignant melanoma, atypical nevi and vitiligo. If there is any atypical appearance or irregularity to the nevus, it should be excised for histological examination. If the halo nevus has a benign appearance, no treatment or removal is necessary. However the patient should be followed for periodic skin exams. Daily sun protection and sunscreen use is encouraged.

References:
James W.D., Berger T.G., Elston D.M. Andrews’ Diseases of the Skin. 10th ed. Philadelphia: Elsevier Inc, 2006, pp. 689-690.

External links: www.dermtext.com, www.emedicine.com

Lela Lankerani, D.O.
Department of Dermatology
Philadelphia College of Osteopathic Medicine/Frankford Hospital
Philadelphia, Pennsylvannia.