Halo naevus (Sutton's naevus)

Meet the patient — the teenager with a vanishing mole

A 14-year-old girl is brought by her mother, who is convinced the mole on her daughter's upper back "is turning into cancer". Three months ago it was an ordinary brown spot; now it sits in the centre of a perfect ring of pure white skin, 1 cm across, with the brown mole itself starting to look paler in the middle. The girl feels nothing — no itch, no pain, no bleed — and on closer inspection she has two smaller identical halos further down her back. Her aunt has vitiligo.[1][4]

Two questions decide every "white ring around a mole": is the halo symmetric and the central naevus benign-looking, in a child, with multiple lesions? (then it is a Sutton's naevus — reassure) and could this instead be a fully regressed melanoma? (the solitary adult halo without a central naevus — biopsy). Answer those two and you have the entire topic.[1][7]

A benign mole that the immune system is dismantling — definition

A halo naevus — Sutton's naevus, halo mole, historically leucoderma acquisitum centrifugum — is a benign acquired melanocytic naevus surrounded by a symmetric, well-demarcated ring of depigmented (white) skin. The white halo is the visible signature of a T-cell-mediated autoimmune attack that destroys both the naevus cells and the surrounding normal epidermal melanocytes.[1][4]

The Latin name leucoderma acquisitum centrifugum — "acquired white skin spreading outward" — captures the phenomenon precisely: the halo expands centrifugally from the central pigmented mole. The lesion looks alarming to patients and parents, but it is benign and self-limiting, with a predictable four-stage evolution: halo forms around a pigmented naevus, the central naevus progressively fades and disappears, the residual depigmented macule gradually repigments.[5]

The same autoimmune mechanism links halo naevus to vitiligo — both are driven by T-cell recognition of melanocyte differentiation antigens — which is why the two coexist, and why the assessment always includes a search for vitiligo and autoimmune thyroid disease.[6]

The four-stage evolution — and the halo-phenomenon umbrella

Halo naevus is one clinicopathological entity, but its natural history unfolds in four reproducible stages first described in the classic literature and still the framework examiners expect. Knowing the stages is essential because a lesion can present at any point in the sequence, and the patient's anxiety is usually driven by the change itself.[1][5]

[1]

The halo phenomenon itself is not restricted to common acquired naevi. The same immune event can encircle congenital naevi, Spitz naevi, blue naevi, dysplastic (atypical) naevi, melanoma, and even non-melanocytic lesions (angiokeratoma, dermatofibroma, seborrhoeic keratosis, or a tattoo). The umbrella term "halo phenomenon" covers all of these; "halo naevus" is reserved for the benign acquired melanocytic naevus with halo. The distinction is a common viva trap.[5][8]

Epidemiology — common, under-reported, and an autoimmune marker

Halo naevus is common but under-reported, because most lesions are never shown to a clinician. The estimated prevalence is around 1 per cent of the general population, with peak incidence in the second decade of life.[1][4]

[1]

Established associations are age (children and adolescents dominate), personal or family history of vitiligo or autoimmune thyroid disease, and a familial tendency — multiple family members with halo naevi are described, suggesting a heritable autoimmune predisposition. There is no clear sex predilection and no strong racial or phototype bias, although the depigmented halo is more visually obvious in darker phototypes. The role of sun exposure is debated; UV is not the driver of the autoimmune response.[1][4]

The most important "risk" is not of the lesion itself but of its associations and mimics. A new halo naevus in a child warrants a screen for vitiligo and thyroid autoimmunity; a new solitary halo in an adult warrants a search for occult melanoma that has triggered the halo phenomenon.[3][7]

Pathophysiology — why the halo is symmetric, why it repigments

The depigmented halo is the visible end-result of a CD8+ cytotoxic T-cell-mediated immune response against melanocyte differentiation antigens — the same family of antigens (Melan-A/MART-1, gp100/Pmel-17, tyrosinase, tyrosinase-related proteins TRP-1 and TRP-2) that drives vitiligo and that melanoma immunotherapy exploits. The response does not discriminate between the naevus melanocytes (which express these antigens abundantly) and the surrounding normal epidermal melanocytes (which express the same antigens) — both are destroyed, producing the symmetric, centrifugal depigmentation that defines the halo.[1][6]

The mechanism is a coordinated cellular and humoral attack. CD8+ cytotoxic T-cells infiltrate the naevus and the epidermis immediately around it, recognising melanocyte antigens on MHC class I and releasing perforin and granzyme to induce apoptosis. Granulysin, a cytotoxic protein released by these T-cells, is markedly upregulated in both halo naevus and vitiligo skin, supporting a shared effector mechanism. Autoantibodies against tyrosinase, Melan-A and gp100 are detectable in serum, but are thought to be a secondary marker of damage rather than the primary effector — the tissue destruction is T-cell driven. Melanophages accumulate in the papillary dermis as pigment is released, producing the faint tan/pink hue of the regressing naevus.[1][6]

Why the halo is symmetric is the question that earns marks. The antigen load is highest at the naevus and falls off concentrically into the surrounding epidermis, so the cytotoxic T-cell response eliminates melanocytes in a uniform radial band. Why it repigments: as naevus cells are themselves destroyed, the antigenic stimulus fades, the T-cell response subsides, and melanocyte stem cells from the outer hair-follicle bulge and adjacent interfollicular epidermis migrate centrally — the same perifollicular repigmentation seen in treated vitiligo.[1][6]

The shared antigenic target explains the strong clinical overlap with vitiligo. In vitiligo the response is systemic and progressive, targeting melanocytes throughout the skin; in halo naevus it is localised to one naevus and its immediate surround and is self-limited. The same susceptibility genes and effector T-cells are involved — which is why a halo naevus can be the first presentation of vitiligo.[6]

The melanoma paradox — when the halo is the good news and the trap at once

The halo phenomenon is occasionally triggered by melanoma itself. The immune system mounts a successful response against the tumour (which expresses the same melanocyte antigens, abundantly), destroying melanoma cells and surrounding normal melanocytes — leaving a depigmented halo at the site of a regressed melanoma that can closely mimic a benign halo naevus. This is the biological basis of the cardinal rule: a solitary halo without a central naevus in an adult must be biopsied. The immune response is both a marker of good prognosis (it has destroyed the tumour) and a trap (it has hidden it).[3][7]

Clinical presentation — four pillars of the bedside diagnosis

The classic halo naevus at presentation (Stage 1) is a brown, dark-brown or pink-brown melanocytic naevus at the centre, surrounded by a symmetric, uniform-width ring of pure white (depigmented) skin — the halo. The halo is sharply demarcated from surrounding normally pigmented skin and is complete (it encircles the entire naevus, with no gaps). The central naevus is usually 3–6 mm, round or oval, and otherwise typical — no asymmetry, border irregularity, colour variegation, or diameter over 6 mm in its own right.[1][4]

The distribution favours the trunk — the back (especially upper back and scapular area) more than the chest and abdomen — followed by the proximal limbs and, less often, the head and neck. Lesions on palms, soles, genitalia and mucosa are rare but described. The predilection for the trunk mirrors the distribution of common acquired naevi generally, since halo naevus is essentially a common naevus plus an immune event.[1][4]

Halo naevi are multiple in over half of cases, with two to ten lesions occurring simultaneously or sequentially over months to years. New halo naevi can continue to appear throughout adolescence, each running its own four-stage course independently — a source of parental anxiety but a typical, benign pattern. Agminated halo naevi (multiple halos clustered within one area) and generalised halo naevi are rarer patterns.[1][8]

A classic halo naevus is asymptomatic — no pain, itching, burning, bleeding or ulceration. The presence of any symptom (pain, pruritus, bleeding, crusting, ulceration, rapid growth, surrounding erythema) is a red flag that the lesion may not be a halo naevus and mandates biopsy to exclude melanoma with regression.[7]

Examiners probe the atypical presentations deliberately. Adult onset (over 40) is unusual; the priority is to exclude melanoma with regression. Solitary lesion should be examined carefully for atypia of the central lesion. Halo without a central naevus may be Stage 3 halo naevus in a child, but in an adult must raise regressed melanoma. Asymmetric or irregular halo (thicker on one side, notched, geometrically irregular) is atypical — exclude melanoma. Halo around an atypical naevus or congenital naevus is a halo-phenomenon variant, not classic Sutton's. Darker phototypes make the halo more striking; repigmentation can be incomplete and postinflammatory hyperpigmentation can complicate the picture.[1][5][8]

Differential diagnosis — the lesion you must never miss

The differential of "a pigmented lesion with surrounding white skin" is one of the highest-yield areas of this topic, because the single most dangerous error is mistaking a regressed melanoma for a benign halo naevus.[3][7]

Two clinical rules govern the differential. First, a typical halo naevus in a child or adolescent — symmetric halo, benign central naevus, multiple lesions, asymptomatic — is a clinical diagnosis that requires no investigation. Second, any atypical feature (solitary, adult onset, asymmetric halo, changing lesion, symptomatic, central lesion with any ABCDE feature) mandates dermoscopy and biopsy to exclude melanoma.[3][7]

Melanoma with regression is the lesion that must never be missed. The clinical clue is asymmetry, irregular border, colour variegation, diameter over 6 mm, and evolution (ABCDE), with any history of change, bleeding or itching. The halo in regressed melanoma is often irregular, asymmetric or geographic rather than the uniform ring of a halo naevus, and the patient is more likely to be an adult. Dermoscopy may show regression structures (scar-like depigmentation, peppering/blue-grey granules) alongside residual atypical melanoma features (atypical network, streaks, blue-white veil, atypical vessels). The decision rule is absolute: a solitary halo without a central naevus in an adult, or any asymmetric or changing halo, is biopsy-mandatory.[3]

Vitiligo is the closest biological cousin. The distinction is one of distribution and pattern: vitiligo produces multiple, often symmetric, depigmented macules on the face, hands, flexures and extensor surfaces; a halo naevus is one naevus with its own surrounding halo. When a patient has both, the diagnosis is straightforward.[1]

Post-inflammatory hypopigmentation follows an identifiable inflammatory event (eczema, psoriasis, tinea, a burn, a resolved infection) at the same site. The hypopigmentation is off-white rather than pure white, ill-defined rather than sharply demarcated, and there is no central naevus. It resolves over weeks to months.[1]

Naevus depigmentosus is a congenital or early-childhood stable hypopigmented patch that does not change, has no central naevus, and shows an off-white colour under Wood's lamp (in contrast to the pure white, accentuated depigmentation of vitiligo or a halo naevus). It is a developmental pigmentary mosaicism, not an immune event.[1]

Meyerson's naevus is the other "halo" naevus examiners name. It is a melanocytic naevus surrounded by an eczematous (red, scaly, pruritic) halo — inflammatory, not depigmented. Histology shows spongiotic eczema overlying the naevus, and the lesion resolves with a topical corticosteroid. Confusing Meyerson's naevus with Sutton's naevus is a classic viva trap: the former is eczematous and red, the latter is depigmented and white.[1]

Piebaldism is a congenital, autosomal dominant leukoderma with a characteristic forelock and stable depigmented patches, present from birth. Chemical leukoderma follows exposure to depigmenting chemicals (phenols, catechols in adhesives, rubber gloves, hair dyes, cleaning agents); there is no central naevus, and the history identifies the cause.[1]

Clinical and bedside assessment — two questions, one Wood's lamp

The assessment is built around two questions: is this really a halo naevus? and, if yes, does this patient have vitiligo or thyroid autoimmunity?[1]

Begin with inspection under good lighting, examining the lesion and the surrounding skin. Confirm the four clinical pillars: a benign-appearing central naevus, a symmetric uniform-width halo, asymptomatic course, and the right demographic (child or adolescent). Look specifically for the features that demand biopsy — asymmetry, irregular border, colour variegation, diameter over 6 mm, evolution (ABCDE), and any symptom — and examine the central naevus with a dermatoscope.[1]

Because halo naevi are multiple and coexist with vitiligo, always examine the whole skin, not just the presenting lesion. Inspect the face, peri-orificial skin, hands, wrists, axillae, groin, knees and elbows for depigmented macules of vitiligo, and check the neck for goitre and the hands for signs of thyroid disease (bradycardia, slow-relaxing reflexes, dry skin for hypothyroidism). Take a focused autoimmune history — vitiligo, thyroid disease, type 1 diabetes, Addison's disease, pernicious anaemia, alopecia areata — in the patient and first-degree relatives.[1]

Wood's lamp (long-wave ultraviolet light) is a useful bedside adjunct: the depigmented halo fluoresces bright pure white under Wood's lamp, confirming complete loss of melanin (as in vitiligo) and distinguishing it from the off-white hypopigmentation of post-inflammatory change or naevus depigmentosus, which does not fluoresce.[4]

Investigations — the diagnosis is clinical, the biopsy is selective

For a typical halo naevus in a child or adolescent — symmetric halo, benign central naevus, multiple lesions, asymptomatic — the diagnosis is clinical and no investigation is required. The history, morphology and demographic are diagnostic; performing biopsies or bloods on a typical lesion adds cost, scarring and anxiety without changing management.[1][4]

Dermoscopy is the key bedside tool for the typical lesion and, more importantly, for the atypical lesion where melanoma must be excluded. The classic dermoscopic features are: a regular globular (brown dots/globules of nested naevus cells at the dermoepidermal junction) or homogeneous brown central naevus with symmetric, regular architecture (globular in children, homogeneous or combined in adolescents); a structureless, pure white surrounding halo, uniform in width, with no pigment network (no melanocytes producing melanin); and, as the naevus regresses, central globules become fewer, smaller and lighter, may show regression structures (blue-grey granules, peppering from melanophages), and finally disappear, leaving only the white structureless area.[1][2]

Equally important are the features that are absent in a halo naevus: no atypical pigment network, no streaks/pseudopods, no blue-white veil, and no atypical (dotted/linear/polymorphous) vessels in the central lesion. The presence of any of these should prompt biopsy, because a regressed or regressing melanoma can display a depigmented halo indistinguishable from that of a halo naevus.[3][7]

Biopsy is indicated whenever the clinical or dermoscopic picture is not that of a typical halo naevus — a solitary halo without a central naevus in an adult (possible fully regressed melanoma); an asymmetric, irregular, or geometric halo around a pigmented lesion; a central naevus with any ABCDE feature; any symptomatic lesion (pain, itching, bleeding, ulceration, rapid growth); or a changing lesion, or any lesion that does not behave as expected over follow-up. When biopsy is performed, a full-thickness excisional biopsy (complete excision with a 2 mm margin) is preferred where melanoma is genuinely suspected, to allow complete histological assessment; a punch or shave biopsy may be acceptable where melanoma is not the leading concern.[3][7]

When a halo naevus is biopsied, the cardinal histological features are: a dense, band-like lymphocytic inflammatory infiltrate at the dermoepidermal junction and superficial dermis, embracing the naevus cells in a "brace-like" or "moth-eaten" pattern (naevus cell nests infiltrated and disrupted by lymphocytes, predominantly CD8+ cytotoxic T-cells); naevus cells may show regression changes — apoptosis, diminished pigment, reduced nest size; in late-stage lesions naevus cells are absent; melanophages in the papillary dermis; loss of epidermal melanocytes in the halo region (confirmed on Melan-A/MART-1 or SOX10 immunostain); and, crucially, absence of cytological atypia (no severe atypia, no mitoses, no pagetoid scatter) — which distinguishes halo naevus from melanoma.[1][5]

When a patient has multiple halo naevi, screening is appropriate: a full skin examination for vitiligo; thyroid function tests (TSH, free T4) and anti-thyroid peroxidase antibodies (anti-TPO) for autoimmune thyroid disease (Hashimoto's thyroiditis most commonly; Graves' disease less often); and, in selected cases, screening for other autoimmune diseases (type 1 diabetes, Addison's disease, pernicious anaemia, alopecia areata) if clinical features suggest them. No imaging is required for a typical halo naevus.[1][4]

Management — reassure, observe, sun-protect; biopsy the atypical

Halo naevus is not an emergency; a confirmed typical lesion needs no urgent treatment. The "resuscitation" step here is really a diagnostic safety step: when a patient presents with a "new white ring around a mole", the immediate priority is to exclude melanoma by careful clinical examination and dermoscopy, and to biopsy if there is any atypical feature — never to reassure on the basis of a presumed "halo naevus" without confirming the diagnosis. Equally, when multiple new halo naevi appear in an adult, the priority is a full skin examination for occult melanoma rather than dismissing the eruption as benign.[3][7]

The management of a confirmed halo naevus rests on a simple principle: reassure and observe; intervene only for cosmetic concern or diagnostic uncertainty.[1][4]

Step 1 — Reassure, observe, and sun-protect

For a typical halo naevus in a child or adolescent, the correct management is reassurance: explain that the lesion is benign, that it is not a cancer, that the central naevus will gradually regress and disappear, and that the white halo will eventually repigment over months to years. This is both the safest and the most cost-effective option and should be the default.[1][4]

Photograph the lesion at baseline and re-examine in 6 to 12 months to document the expected regression; serial photographs are reassuring for the family and provide objective evidence of the benign course. Sun protection of the depigmented area is essential — without melanin, the halo skin burns easily — using clothing, shade, and a broad-spectrum SPF 30+ sunscreen reapplied regularly.[4]

Step 2 — Screen for autoimmune associations (if multiple)

When a patient has multiple halo naevi, screen for vitiligo and autoimmune thyroid disease: a full skin examination for depigmentation, and TSH with anti-TPO. If thyroid disease is detected, manage it on its own merits (levothyroxine for hypothyroidism, endocrine referral as needed). If vitiligo is present, manage it according to vitiligo guidelines (topical corticosteroid or calcineurin inhibitor, NB-UVB, or topical ruxolitinib in selected cases).[1]

Step 3 — Cosmetic treatment of persistent depigmentation

In a minority the depigmented halo persists for years (or permanently) and is a significant cosmetic concern, especially on visible sites or in darker phototypes. When repigmentation is desired, the same treatments used for localised vitiligo are appropriate, because the underlying mechanism is the same.[1][6]

Repigmentation, when it occurs, typically appears first as perifollicular brown macules — melanocyte precursors repopulating from the hair-follicle bulge — and gradually expands to fill the halo. The response is slow (months) and often incomplete; patients should be counselled that perfect repigmentation is not guaranteed.[1]

Step 4 — Biopsy or excise if atypical

The one situation in which the "reassure and observe" pathway does not apply is the atypical lesion. Biopsy — preferably excisional — is mandatory for a solitary halo without a central naevus in an adult (possible regressed melanoma); an asymmetric, irregular, or changing halo around a pigmented lesion; any central naevus with ABCDE features or any symptom (pain, itching, bleeding); or a lesion that fails to behave as expected over follow-up (a halo naevus that does not regress, or that enlarges, darkens, or becomes symptomatic).[3][7]

Topical calcineurin inhibitors (tacrolimus 0.1% ointment, pimecrolimus 1% cream) are applied twice daily to the depigmented area for 3 to 6 months; they are steroid-sparing and the preferred choice on the face, neck and intertriginous skin where topical corticosteroids cause atrophy. Local burning and itching are common in the first week and usually settle.[6]

The 308 nm excimer laser delivers targeted UVB to the depigmented macule in sessions two to three times weekly for several months; it is best suited to small, localised lesions and is the treatment of choice when a single persistent halo on a visible site is the cosmetic concern. Erythema and occasional blistering are the main side effects. Narrowband UVB (NB-UVB) phototherapy (311 nm) is reserved for widespread depigmentation, typically in a patient with multiple halo naevi and coexistent vitiligo; treatment is two to three times weekly, with repigmentation appearing slowly over months as perifollicular macules. The cumulative lifetime UV dose should be tracked.[1]

For a typical lesion under observation, follow-up is pragmatic rather than scheduled: a baseline photograph and a review at 6 to 12 months to confirm the expected regression, then return-as-needed advice. For a lesion that has been excised for atypia and confirmed benign, no further follow-up is required. New halo naevi may continue to appear through adolescence; the patient and family should be reassured that each runs the same benign course.[1]

Specific subtypes and scenarios — the variants that examiners name

The same autoimmune event can encircle lesions other than a common acquired naevus. These are variants of the halo phenomenon, not classic Sutton's naevus, but they are examined and worth knowing. Halo congenital naevus develops a symmetric halo around a congenital melanocytic naevus; benign, but the central lesion is followed for the usual congenital-naevus considerations. Halo Spitz naevus — a Spitz naevus (a benign but histologically alarming pink papule in children) with a halo — needs histology because Spitzoid melanoma is in the differential. Halo blue naevus keeps its blue colour because dermal melanocytes are spared. Halo dysplastic (atypical) naevus is biopsied to grade the atypia of the central lesion. The halo phenomenon can even encircle seborrhoeic keratosis, dermatofibroma, angiokeratoma, basal cell carcinoma, and tattoos.[5]

Agminated halo naevi — multiple halos clustered within a single anatomical area, sometimes in a segmental or dermatomal distribution — are a rare recognised pattern; they follow the same benign course but suggest a more localised triggering event.[8]

A patient (often a child) presenting with multiple new halo naevi may develop generalised vitiligo months to years later — the halo naevi are the first manifestation of the underlying autoimmune diathesis. These patients should be examined periodically for new depigmentation, counselled about the possibility, and screened for thyroid autoimmunity.[1][6]

The most important subtype to recognise is the halo phenomenon triggered by melanoma — the immune system has destroyed the tumour, leaving a depigmented halo with no (or minimal) residual pigmented lesion. This is rare but is the reason for the cardinal rule: a solitary halo without a central naevus in an adult must be biopsied. A patient with multiple new halo naevi and a personal or family history of melanoma should have a full skin examination for occult melanoma, since the generalised halo phenomenon can be a paraneoplastic immune response to a melanoma elsewhere.[3][7]

Complications and pitfalls — three classic traps

In their natural state, halo naevi cause few problems. The complications that matter are largely cosmetic and psychological: sunburn of the depigmented halo (without melanin it burns easily; sun protection is essential); cosmetic distress (especially for facial, hand, or widespread lesions, or in darker phototypes where contrast is greatest); psychological distress in children and adolescents (anxiety about a "changing mole" and fear of cancer — reassurance is itself a treatment); and incomplete repigmentation (the halo may persist permanently as a depigmented macule).[1][4]

Treatment-related complications follow the agents used. Topical corticosteroids can cause skin atrophy, telangiectasia, and striae if used too long, especially on the face and folds — a calcineurin inhibitor is preferred at these sites. Excimer laser and NB-UVB can cause erythema, blistering, and (in darker skin) postinflammatory hyperpigmentation, and the cumulative UV dose must be tracked. Biopsy and excision carry the usual risks of scarring, infection, and dyspigmentation, but these are acceptable when melanoma is in the differential.[1]

Prognosis and disposition — uniformly benign, the mole disappears

The prognosis of halo naevus is uniformly benign: the central naevus regresses and disappears (typically over 6 to 12 months from onset of the halo), and the halo gradually repigments over months to years (often 1 to 5 years), sometimes incompletely or not at all. No halo naevus itself undergoes malignant transformation; the only malignant concern is the melanoma that mimics a halo naevus, not the halo naevus itself. New halo naevi may continue to appear through adolescence; each runs the same benign independent course.[1][4]

Typical lesions are managed in primary care or in general dermatology outpatient clinics. Specialist referral is appropriate for atypical lesions where melanoma cannot be confidently excluded, for widespread depigmentation with significant cosmetic impact, and for the patient with multiple halo naevi and an autoimmune diathesis who needs screening and counselling. The safety-net for every patient is clear advice to return if the lesion changes colour, shape or size, becomes symptomatic, or if new halo naevi appear in adulthood.[1]

Special populations — children, adults, darker phototypes

Children and adolescents are the typical population. The priorities are to reassure the patient and parents, to confirm the diagnosis clinically (avoiding unnecessary biopsy), to provide baseline photography, and to screen for vitiligo and thyroid autoimmunity when lesions are multiple. Sun protection of the depigmented area is essential. Counselling should address the natural history (the mole will fade and disappear, the halo will eventually repigment) and the benign prognosis.[4]

A first halo naevus in an adult, especially over 40, is unusual; the priority is to exclude melanoma with regression by dermoscopy and biopsy if there is any atypical feature or if the lesion is solitary without a central naevus. The generalised halo phenomenon in an adult also warrants a full skin examination for occult melanoma.[3][7]

In darker phototypes (Fitzpatrick IV–VI), the depigmented halo is more visually striking and may cause greater cosmetic distress; repigmentation can be incomplete and postinflammatory hyperpigmentation can complicate any inflammatory treatment. Sun protection is essential. Topical calcineurin inhibitors are preferred over topical corticosteroids on the face and folds, and excimer laser can be effective for localised lesions.[6]

Patients with known vitiligo, autoimmune thyroid disease, type 1 diabetes, Addison's disease, or alopecia areata are more likely to develop halo naevi. These patients should be examined for new halo naevi (usually benign, needing no treatment) and counselled about the shared autoimmune mechanism. Coexistent thyroid disease should be managed on its own merits. Halo naevi are not specifically increased in the immunocompromised; pregnancy does not specifically affect them, but any pigmented lesion arising or changing in pregnancy still requires dermoscopy to exclude melanoma.[1]

Evidence, guidelines, and where practice converges

The classic clinicopathological framework was established by the 1995 case series of 142 halo naevi (Mooney, Barr, Buxton), which defined the morphology, symmetric halo, natural four-stage history, and the broad range of lesions that can carry the halo phenomenon — distinguishing "halo naevus" (classic Sutton's) from the wider "halo phenomenon".[5] The 2015 review (Weyant, Chung, Helm) consolidates the clinicopathological criteria, the histology (dense CD8+ lymphocytic infiltrate embracing naevus cells, regression, melanophages), the differential from melanoma, and the management ladder, and remains the best single modern reference.[1] The 2024 Scientific Reports study (Hlača et al.) demonstrates marked upregulation of granulysin in both halo naevus and vitiligo skin — the modern molecular signature of a shared T-cell effector mechanism.[6]

[1] [1]

The main controversies are minor. First, whether any treatment is warranted for the persistent halo in a child — most authorities recommend reassurance and camouflage over active treatment, reserving topical calcineurin inhibitors or excimer laser for cases of significant cosmetic distress. Second, the threshold for biopsy of an atypical lesion in a child: some clinicians biopsy aggressively to exclude a Spitzoid lesion or melanoma, while others rely on dermoscopy and short-interval follow-up. Third, the optimal screening strategy for autoimmune associations (how extensive the workup should be) varies; most guidelines recommend TSH and anti-TPO and a full skin examination, with further testing only if clinically indicated.[1]

Exam pearls — the high-yield list

The mantra: Symmetric halo in a child, multiple lesions, asymptomatic — reassure; solitary halo in an adult without a central naevus — biopsy for melanoma.[1][7]

Etymology for viva gold: Sutton is Richard Lightburn Sutton, the American dermatologist who described the lesion in 1916 as leucoderma acquisitum centrifugum. Naevus is Latin for "birthmark" (from nasci, to be born); halo is Greek for "threshing floor" — the circular band of ground around the threshing floor that gave us both the saintly glow and the white ring around a mole.[1]

Ward-round test — three stems, thirty seconds each

Stem 1 — the teenager with a vanishing mole (answer)

A 14-year-old girl has a symmetric white halo around a benign-appearing brown mole on her upper back, with two smaller identical halos nearby. Her aunt has vitiligo. What is the diagnosis, the natural history, and the management? Model: This is a classic halo naevus (Sutton's naevus) — symmetric halo, benign central naevus, multiple lesions, asymptomatic, in an adolescent. The natural history is the four-stage evolution: halo forms, naevus fades, naevus disappears leaving a depigmented macule, halo repigments over months to years. Management is reassurance, baseline photography, sun protection, and review at 6–12 months; because lesions are multiple and there is a family history of vitiligo, also do a full skin examination for vitiligo and TSH with anti-TPO. No biopsy.[1][4]

Stem 2 — the solitary adult halo (answer)

A 45-year-old woman presents with a single 8 mm round depigmented macule on her back, with no central pigmented lesion, appearing over three months. What is your concern and what must you do? Model: The concern is melanoma with regression — a fully regressed melanoma can leave a depigmented halo with no visible residual tumour, closely mimicking a halo naevus. Unlike a halo naevus, this is a solitary lesion in an adult with no central naevus — the three red flags. The correct action is a full skin examination for a primary melanoma elsewhere (the halo may be a paraneoplastic immune response), and biopsy of the depigmented lesion — preferably an excisional biopsy — for histology. Even if no melanoma cells remain, the histology may show melanophages and a lymphocytic infiltrate consistent with a regressed melanoma, which still requires staging and surveillance. Never reassure a solitary adult halo without histology.[3][7]

Stem 3 — the red, scaly halo (answer)

A 10-year-old boy has a mole on his arm surrounded by a red, scaly, itchy ring that has appeared over two weeks. The ring is not white. His mother thinks it is a halo naevus. What is it really, and what do you do? Model: This is Meyerson's naevus, not Sutton's naevus — a melanocytic naevus surrounded by an eczematous (red, scaly, pruritic) halo, not a depigmented one. Histology shows spongiotic eczema overlying the naevus. The lesion resolves with a topical corticosteroid. Confusing Meyerson's naevus with Sutton's naevus is a classic viva trap: Meyerson's is eczematous and red, Sutton's is depigmented and white.[1]

References

1. [1]Weyant GW, Chung CG, Helm KF. Halo nevus: review of the literature and clinicopathologic findings Int J Dermatol, 2015.PMID 26146814
2. [2]Ko E, Panchal N. Pigmented Lesions Dermatol Clin, 2020.PMID 32892857
3. [3]Dessinioti C, Geller AC, Stratigos AJ. A review of nevus-associated melanoma: What is the evidence? J Eur Acad Dermatol Venereol, 2022.PMID 35857388
4. [4]Bandyopadhyay D. Halo nevus Indian Pediatr, 2014.PMID 25362030
5. [5]Mooney MA, Barr RJ, Buxton MG. Halo nevus or halo phenomenon? A study of 142 cases J Cutan Pathol, 1995.PMID 7499574
6. [6]Hlača N, Vičić M, Kaštelan M, et al. Analysis of granulysin expression in vitiligo and halo-nevus Sci Rep, 2024.PMID 39020008
7. [7]Langford MA, Al-Ghazal SK. Halo naevus or malignant melanoma: A case report JPRAS Open, 2018.PMID 32158818
8. [8]Hassab-El-Naby HMM, Rageh MA. Agminated Halo Nevus: A Novel Presentation Am J Dermatopathol, 2023.PMID 36939134