A halo mole is a mole with a white ring, or halo, around it.

Halo moles are not uncommon and are usually seen in children or young adults of either sex. For reasons which are unknown, the body selects a particular mole or moles for destruction. This is presumably because the mole is recognized as being abnormal in some way. The mole in the center of a halo is rarely malignant (cancerous) Although all halo moles need to be examined carefully by a dermatologist.

Sometimes halo moles are triggered by sunburn which damages the mole and causes it to be recognized by the body as foreign. 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, eventually disappearing completely. Some of the reaction affects the normal skin around the mole, which also has pigment cells in it, causing the white halo. This is usually about one quarter to one half inch wide, usually on the trunk. They are less common on the head, and are rare on the limbs. They develop at intervals round one or several moles but not all.

Once the mole in the center of the halo disappears, repigmentation can occur. This can sometimes take several years.

Treatment

If you have a halo mole, get your dermatologist to check it. Halos can be seen as part of a more generalized pigment loss, vitiligo, or in melanoma.