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A halo nevus is a benign skin lesion commonly found in children, but it can be found in individuals of any age. It is actually a mole surrounded by an area of white halo. These moles appears equally in both men and women, and is only a cosmetic abnormality. Treatment is not necessary since it is benign.
Leukoderma acquisitum centrifugum was the first name given to this condition by an American dermatologist named Richard L. Sutton. This skin condition is a variant of melanocytic nevus, a skin lesion that contains melanocytes or pigment cells. In halo nevus, there is lymphocytic infiltration surrounding the nevus. The infiltrate is responsible for the zone of depigmentation, which is the area of white halo surrounding the nevus.
Although the exact cause of this skin lesion is unknown, many researchers have attempted to explain its immunological mechanism. The infiltrating cells consist predominantly of T-lymphocytes, which include CD8 and CD4 lymphocytes. There are also scattered macrophages in the area of the white halo. Melanocytes are completely absent in the area of the white halo. The role of T-lymphocytes on the absence of melanocytes is not yet clear, but it is plausible that T-lymphocytes attack and kill melanocytes.
A halo nevus is usually single and seen most frequently on the trunk, especially on the back. In some cases, it may be multiple and can be found anywhere on the body. The nevus appears as round or oval. It may be uniformly colored as brown, pink, or tan, and is centrally located within the surrounding halo. The width of the halo surrounding the nevus is variable, but its radial distance from the nevus is generally consistent.
The central nevus may persist or disappear over months or years, with the area of the white halo left behind. Its coloration may not change, may become irregular, or change into pink or red. Disappearance of the nevus with repigmentation of the halo is also possible. The halo, however, persists in most cases.
A halo nevus produces no symptoms, and no treatment is required. Any atypical appearance or irregularity, however, warrants excision for histological examination in order to rule out malignancy. It is important for a doctor to ask patients with halo nevus about past medical history or family history of atypical nevi, malignant melanoma, and vitiligo. Individuals with halo nevus must be followed up yearly for complete skin examination to ensure that no atypical moles or malignant melanoma have developed. Daily use of sunscreen is also encouraged.