A halo mole (or halo naevus) is a mole with a white ring, or halo, around it. It is sometimes known as Sutton naevus or leukoderma acquisitum centrifugum.
Halo moles are not uncommon and are usually seen in children or young adults of either sex.
What do they look like?
There are four stages of a halo naevus. It may take several years to complete the cycle.
|Stage 1||A rim of pale skin surrounds a mole|
|Stage 2||The mole may become pinker or less pigmented, and fades away|
|Stage 3||A circular or oval area of depigmentation persists|
|Stage||The affected skin gradually returns to its normal colour|
Why do they arise?
For reasons which are unknown, the body selects a particular mole or moles for destruction. This is presumably because the mole is recognised as being abnormal in some way. It is considered an autoimmune process.
The mole in the centre of a halo is rarely malignant (cancerous) although all halo moles need to be examined carefully by an appropriate medical practitioner. A malignant mole is called a melanoma, and these may sometimes develop white halos around them as well.
Sometimes halo moles are triggered by sunburn which damages the mole and causes it to be recognised 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 0.5 to 1.0 cm 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.
If you have a halo mole, get your dermatologist or doctor to check it. A full skin examination should be performed, as rarely, halo moles can be triggered by the presence of a malignant melanoma elsewhere on the skin. Halos can be seen as part of a more generalised pigment loss, vitiligo, or in melanoma.
Apart from an explanation, no treatment is normally required. However sunscreen should be applied to all the skin during summer to prevent sunburn. The white skin of a halo naevus will burn particularly easily in the sun because it is missing protective melanin pigment.