Clinical Hours: Mon-Fri, 8AM - 3PM(905) 493-5700
1885 Glenanna Road, Suite 220, Pickering, ON, L1V 6R6
A halo nevus is a mole encircled by a ring of white, depigmented skin. Learn about its autoimmune cause, four stages, diagnosis, and when treatment is needed.
A halo nevus, also known as a halo mole or Sutton nevus, is an ordinary mole that becomes encircled by a ring of pale, depigmented skin. The white rim gives the lesion a distinctive target-like appearance and reflects a localized loss of melanin pigment in the skin immediately surrounding the central mole.
Halo nevi are a relatively common finding, estimated to affect approximately 1 percent of white-skinned individuals. They are seen most often in healthy children and young adults, although they can also appear later in life. A single lesion or several halo nevi may be present at the same time. Over a period of months to years, many halo nevi fade completely and the surrounding skin gradually regains its normal colour.
The precise trigger for a halo nevus is not fully understood, but the condition is now regarded as immune-mediated. The depigmented halo develops when the immune system mounts a targeted response against the pigment-producing cells, called melanocytes, within and around the central mole [1].
Cytotoxic immune cells. The leading proposed mechanism involves cytotoxic CD8+ T lymphocytes that recognize antigens on the nevus melanocytes and destroy them. Circulating antibodies directed against melanocytes have also been described. This immune reaction extends beyond the mole into the adjacent normal skin, where the loss of melanocytes produces the surrounding ring of depigmentation [1].
Possible triggers. In some individuals, a halo nevus appears after local trauma to the mole or after sunburn, events that may expose melanocyte antigens to the immune system and prompt the response. In many cases, however, no clear precipitating factor can be identified.
Halo nevi share important features with vitiligo, a condition characterized by more widespread loss of skin pigment. Both involve immune-mediated destruction of melanocytes, and the two conditions are frequently seen together in the same individual.
In children, multiple halo nevi in particular have been associated with vitiligo and with a personal or family history of autoimmune conditions such as autoimmune thyroiditis. In a retrospective study of children with halo nevi, a notable subset also had vitiligo at presentation, and a small number of those with halo nevi alone went on to develop vitiligo during follow-up, most often those with multiple lesions [2].
Research has also sought to identify which patients with halo nevi are most likely to go on to develop vitiligo, so that closer monitoring can be offered to those at higher risk. Identified risk factors include the Koebner phenomenon, multiple halo nevi, and a family history of vitiligo [3]. The presence of halo nevi alone, however, does not mean that vitiligo or another autoimmune condition will necessarily follow.
Halo nevi most often develop on the trunk, and the back is a particularly common site. The head, neck, and limbs are affected less frequently. The central mole is usually an ordinary melanocytic naevus that was present from early childhood or acquired during the growing years.
The surrounding white halo is typically round or oval and symmetrical, and it commonly measures between 0.5 and 1 centimetre across. The depigmented zone is uniform in colour, and the border between the pale ring and the normal surrounding skin is usually well defined.
A halo nevus tends to evolve through a recognizable sequence of changes. The complete cycle unfolds gradually; the interval between the first appearance of the halo and full resolution often spans several years, and these lesions commonly persist for a decade or longer [4].
Not every halo nevus passes through all four stages, and the central mole does not always disappear. In some cases the halo persists for a prolonged period, and repigmentation may be slow or remain incomplete [4].
A halo nevus is usually diagnosed clinically, based on the characteristic appearance of a central mole surrounded by a symmetrical white ring. Examination with dermoscopy, a handheld magnifying technique that allows detailed inspection of the colours and structures within a lesion, supports the diagnosis and helps confirm that the central mole is benign.
In children and young adults with an otherwise typical halo nevus, no further investigation is generally required. In adults, and particularly when a halo nevus appears for the first time later in life, an annual complete skin examination is recommended [5].
This rationale reflects two findings. First, a depigmented halo can form around a mole that is histologically atypical, spanning a wide spectrum of atypia [6]. Second, a new-onset halo nevus in an adult has been associated with a small increase in the likelihood of melanoma [5]. For this reason, any central lesion with irregular, asymmetric, or changing features warrants careful evaluation.
A typical halo nevus requires no treatment. The condition is benign, and in many cases the mole and its halo resolve on their own without any intervention.
Sun protection. The pale skin of the halo has lost its protective melanin and therefore burns easily. Covering the area or applying a broad-spectrum sunscreen during sun exposure helps prevent sunburn and reduces ultraviolet damage to the depigmented skin.
When surgery is considered. Surgical removal is not necessary for a typical halo nevus. Excision may be recommended when the central mole shows atypical or concerning features, such as an irregular outline, uneven colour, or asymmetry. In that situation the lesion can be surgically removed and examined under the microscope to exclude melanoma.
Most halo nevi are harmless and require only reassurance. A dermatologist should be consulted if a halo develops around a mole during adulthood, if the central mole looks unusual or changes in size, shape, or colour, or if numerous new halo nevi appear over a short period. A professional assessment can confirm the diagnosis, exclude more serious conditions, and provide guidance on monitoring.
An evaluation of a halo nevus or any changing pigmented lesion can be arranged through a consultation at the Centre for Medical and Surgical Dermatology.
This article is intended for educational purposes and does not replace professional medical advice. Please consult your dermatologist for personalized recommendations.
Your feedback helps us improve our news and clinical insights
From medical dermatology to surgical procedures, our clinic provides comprehensive care for all skin, hair, and nail conditions.