Lichen sclerosus

Meet the patient

A 68-year-old woman, six years post-menopausal, complains of vulvar itch that wakes her at 3 a.m., tearing dyspareunia, and — the reason she finally came — a bruise on the vulva she cannot explain. On examination the inner labia majora and perianal skin form a continuous figure-of-eight of ivory-white, crinkled, parchment-like skin with petechial purpura inside the plaques; the labia minora have nearly disappeared.[1][5]

Two questions are now live, and the whole page exists to answer them: what is this, and what is the first drug? and what change in this plaque makes you reach for the biopsy punch today rather than the prescription pad?[1]

What LS is — and the three reasons it matters

LS is a chronic, immune-mediated inflammatory dermatosis that produces epidermal atrophy and dermal sclerosis, with a striking predilection for anogenital epithelium. It is uncommon, frequently missed at first presentation, and matters for three reasons: disabling symptoms (intractable pruritus, dyspareunia, dysuria), progressive scarring that destroys vulvar and penile architecture, and a 2-5% lifetime risk of squamous cell carcinoma in genital disease that mandates lifelong surveillance.[1][3][4]

The names are a historical garden you should be able to weed on a viva: kraurosis vulvae (the old gynaecological term for vulvar LS), white-spot disease and Csillag disease (older names for extragenital LS), and balanitis xerotica obliterans (BXO) — the male-genital name for LS of the prepuce, glans and meatus. The modern unified term is lichen sclerosus, used across all sites and both sexes.[1]

Etymology for viva gold: "lichen" is Latin for a tree-moss — the flat, scaly surface — and "sclerosus" is Greek for hard; together, hard, mossy skin. "BXO" survives in urology because it describes what the clinician sees (a dry, obliterating balanitis) better than what the disease is.[1]

LS is also a systemic autoimmune disease with a cutaneous signature. The skin is the most visible target, but the disease clusters with autoimmune thyroid disease, vitiligo, alopecia areata, pernicious anaemia and type 1 diabetes, and carries circulating autoantibodies to BP180 (collagen XVII) and BP230 — the same antigens targeted in bullous pemphigoid.[6]

Who gets it — the two oestrogen troughs

LS strikes at the two ages when oestrogen is lowest: the postmenopausal woman and the prepubertal girl. Add a smaller peak of BXO in men aged 30-40, and you have the epidemiology.[1][3]

[1]

The risk factors cluster into host, autoimmune and local (Koebner) groups. Host: female sex, Caucasian ancestry (rare in deeply pigmented skin), perimenopausal or prepubertal low-oestrogen states, and HLA-DR11, DQ7, DQ9 in familial cases. Autoimmune: a personal or family history of autoimmune disease, present in 20-30% (thyroid disease commonest, then vitiligo, alopecia areata, pernicious anaemia, type 1 diabetes, morphea). Local — the Koebner phenomenon — friction, chronic irritation, surgical and episiotomy scars, radiotherapy ports and lichenification from scratching: LS declares itself where the skin has been provoked.[1][3][5]

Read the surface first — the figure-of-eight and the pathognomonic purpura

In the adult woman the diagnosis is made by reading the surface: ivory-white atrophic plaques in a figure-of-eight around the vulva and anus, with intra-plaque purpura that is pathognomonic. The figure-of-eight — vulva joined to perianal skin across the perineum — is the distribution; the "cigarette-paper" wrinkling is the texture; the non-palpable, non-blanching purpura inside the white plaque is the sign you must not miss.[1][5]

The symptoms that bring her in line up with the anatomy involved:[1][5]

• Intractable vulvar pruritus, worse at night and aggravated by warmth, sweat and friction — the commonest presenting complaint.[1][5]
• Burning and rawness — "the skin feels torn", "like acid on it".
• Dyspareunia from introital stenosis, posterior fourchette fissuring and clitoral involvement; apareunia in advanced disease.
• Dysuria and post-micturition burning from involvement of the urethral meatus and anterior vestibule.
• Constipation and perianal pain from perianal fissuring — classically a paediatric sign but seen in long-standing adult disease too.

The architecture tells you how long the disease has been ignored. Early disease preserves anatomy; established disease adds fissures, hyperkeratosis and confluent plaques; late disease resorbs the labia minora, buries the clitoris under a phimotic hood, and stenoses the introitus and anus into a scarred, narrowed ring. Once architecture is lost it rarely returns fully — which is why under-treatment is the original sin of LS management.[1][5]

[1]

BXO — when the foreskin turns white

In the male, LS is BXO: the same disease in the prepuce, glans and anterior urethra, presenting as phimosis, meatal stenosis and — in the worst case — acute urinary retention. The classic patient is a boy aged 8-15 with phimosis that is "primary" only until someone looks, or a man of 30-40 with phimosis or meatal stenosis, often after a circumcision done for "phimosis" that was unrecognised LS all along.[3][8][12]

• Phimosis — progressive non-retractability; the prepuce is tight, sclerotic and white, with a white sclerotic ring at the coronal sulcus.[3][8]
• Meatal stenosis — fissuring and narrowing of the meatus; urinary spraying, deflection, straining, and in severe cases retention.
• Anterior urethral stricture — sclerosis extending into the navicular fossa and beyond; rare, but the reason the urethra must be assessed, not just the foreskin.
• Sexual dysfunction from pain, phimosis and loss of glans sensation.
• Balanitis — secondary candidal or bacterial infection with fissuring and bleeding.

Circumcision is the definitive surgical treatment for BXO phimosis and biopsy is the diagnostic one — but circumcision does not cure the disease. LS can recur in the circumcision scar by the Koebner phenomenon, so clobetasol continues after surgery, and the glans and meatus stay under annual surveillance for penile SCC. The 2026 BASHH national guideline on balanoposthitis sets the current framework for penile LS.[8][12]

Extragenital LS — the safe cousin

Extragenital LS is the same disease off the anogenital skin, and the one fact that redeems it is that it has no malignant potential. It accounts for 15-20% of LS, may be the only site, and presents as ivory-white, porcelain-like, atrophic macules and patches with a wrinkled surface, follicular plugging and a sharply defined edge on the trunk, upper back, neck, axillae, breasts and wrists.[2]

The patches are usually asymptomatic and come to attention cosmetically. The only reason to treat them is symptoms or appearance (clobetasol, tacrolimus or phototherapy) — never SCC surveillance, which is reserved for genital disease.[2]

The child with perianal bleeding — LS, abuse, or both?

This is the single most consequential mimic in paediatric dermatology, and the only safe answer is "both, until proven otherwise, with biopsy and a multidisciplinary assessment." Prepubertal LS peaks at 5-8 years and presents with perianal bleeding from fissures, constipation from painful defecation, vulvovaginal soreness, dysuria and nocturnal pruritus — the same figure-of-eight of ivory-white atrophic plaques, erosions and haemorrhagic blisters.[9]

• Peak age 5-8 years, sometimes younger.[9]
• Symptoms — perianal bleeding, constipation, vulvovaginal soreness, dysuria, nocturnal pruritus.
• Signs — ivory-white atrophic plaques and erosions in the vulvoperianal area, haemorrhagic blisters, perianal fissuring, figure-of-eight involvement.
• Misdiagnosis — most often confused with sexual abuse (the perianal bruising, fissuring and bleeding can be indistinguishable on inspection), or with chronic constipation, candidiasis or threadworm.
• Treatment — the same ultra-potent topical corticosteroid regimen (clobetasol 0.05% ointment once daily for 4 weeks, then alternate nights, then twice weekly), with careful parental counselling and safeguarding involvement where appropriate.
• Prognosis — up to 50-75% of girls remit at puberty; the rest carry disease into adult life with a persistent SCC risk.

Sober point, because this is a safeguarding block: vulvovaginal LS can itself be caused by chronic friction in the setting of abuse, so the two diagnoses are not mutually exclusive — a child can have both. The Savage 2026 series in Pediatric Dermatology confirms that most children who do not remit at puberty continue to need surveillance into adult life. The cost of a wrong call in either direction is lifelong.[9]

The white-anogenital-plaque face-off

"White plaque on the vulva or glans" is the single most-tested stem in this topic, and it is won or lost on the discriminator beneath each name. Memorise the one-line tell for each, then drop it under the heading on the viva.[1][5][7]

[1]

Dermoscopy — the rosette and the absent network

Dermoscopy helps separate LS from vitiligo and other hypopigmented genital disorders at the bedside: LS shows white structureless areas with four-leaflet "rosettes" (follicular plugging) and comedo-like openings, linear or dotted vessels in the surrounding skin, and an absent pigment network — the opposite of vitiligo's perifollicular repigmentation. Useful, but the diagnosis is still clinico-histological, not dermoscopic.[7]

RED-WHITE-BLUE — the histology you draw on the whiteboard

LS histology is a layered zonation you can draw in three coloured bands — red, white, blue — from surface down, and the band the infiltrate sits in is what separates LS from lichen planus.[1][3]

• RED — epidermis: atrophy (thinned epidermis, loss of rete ridges), hyperkeratosis with follicular plugging, and basal vacuolar degeneration (the interface change).[1][3]
• WHITE — papillary dermis: a homogenised, eosinophilic, glassy, paucicellular band of hyalinisation (sclerosis), with loss of elastic fibres and a thickened, reduplicated basement membrane.
• BLUE — mid-dermis: a band-like lymphohistiocytic infiltrate sitting below the hyalinised zone — the key discriminator from LP, where the infiltrate hugs the interface.
• Subepidermal split — a frequent finding from basement-membrane damage; in the bullous variant it opens into a frank bulla.

Direct immunofluorescence is NEGATIVE in LS — the single most useful lab discriminator from the bullous pemphigoid spectrum. In the bullous variant, linear IgG and C3 may appear at the BMZ and serum anti-BP180 NC16A and anti-BP230 IgG are positive in 23-32% of genital LS — the mechanistic bridge Patsatsi and colleagues drew in 2014.[6]

[1]

Why an ultra-potent steroid TREATS an atrophic disease

This is the paradox every student raises, and the answer is the whole key to LS management. The atrophy of LS is driven by active T-cell inflammation and fibroblast dysfunction — it is inflammatory atrophy, not intrinsic dermal cell loss. Suppress the inflammation with clobetasol and the inflammatory atrophy halts or partially reverses; the steroid-induced atrophy that would terrify you on normal skin is largely irrelevant because the skin is already at end-stage morphology. Clobetasol also damps the IFN-γ and TNF-α milieu that drives malignant transformation — a mechanistic rationale for its chemopreventive effect.[1][4]

The immunopathology in one paragraph. LS is T-cell-mediated: CD4+ and CD8+ lymphocytes with a Th1 profile (IFN-γ, IL-1, TNF-α) dominate, with few B cells. Dermal fibroblasts are hyperproliferative, overproduce type I and III collagen and underproduce elastin, so the papillary dermis loses its elastic-fibre network and the skin becomes fragile and easily bruised. Chronic inflammation injures the subepidermal capillary plexus, dysregulates MMP-2 and MMP-9 and their TIMPs, and the resulting basement-membrane fragility is what produces the pathognomonic purpura and the bullous variant.[1][3][6]

The 12-week taper — clobetasol is the answer to almost every LS question

First-line, gold-standard, and the only induction regimen you need: clobetasol propionate 0.05% ointment, once daily at night for 4 weeks, then alternate nights for 4 weeks, then twice weekly for 4 weeks, then twice weekly for life. BAD, EuroGuiderm and AAD converge on this. Emollients and soap substitutes run alongside it; circumcision is added for BXO phimosis; surgery is reserved for structural complications; and SCC surveillance is annual or biennial for life.[1][4][11]

[4] [4] [1]

Practical application — the fingertip unit. Apply thinly at night to affected areas only: about one fingertip unit (the ointment expressed from a 5-mm nozzle along the distal phalanx of the index finger) covers an adult vulva; about half a unit covers an adult penis; about a quarter to half a unit a prepubertal vulva. Use the smallest effective amount and taper to the minimum effective maintenance dose.[1]

[4]

Steroid-sparing — when tacrolimus earns its place

Topical calcineurin inhibitors are second-line, steroid-sparing, and the FDA black box is not a contraindication in LS. Reach for tacrolimus 0.1% ointment or pimecrolimus 1% cream when clobetasol irritates, when long-term steroid exposure is undesirable, or as a maintenance alternative; the Patel 2026 systematic review found no proven increase in vulvar or penile SCC in LS patients using topical tacrolimus, and the BAD and EuroGuiderm consensus treats TCIs as a reasonable second-line with the caveat of regular examination.[10]

[10] [10]

Surgery is for plumbing, not for the disease

There is no surgical cure for LS. Surgery is for the structural complications — phimosis, meatal stenosis, introital stenosis — and it is done only after the medical disease is controlled, never instead of it. LS recurs in the surgical scar by the Koebner phenomenon, so clobetasol continues post-operatively and surveillance does not stop.[1][4]

[1]

The two SCC traps — biopsy early, biopsy often

Stated plainly, because this is the preventable-harm block. Genital LS carries a 2-5% lifetime risk of squamous cell carcinoma; extragenital LS carries none. The single most important habit in LS care is a low threshold to biopsy any change in a long-standing plaque. The route is the LS to differentiated VIN (dVIN) to SCC sequence, and the ISSVD 2026 terminology standardises the nomenclature for biopsy reporting along that sequence.[1][4][11]

Surveillance is annual or biennial for life, and discharge from specialist care is not recommended. Each review inspects the vulva or penis and perianal skin in good light, palpates for induration and nodules, checks the inguinal nodes, biopsies anything new, reinforces monthly self-examination, addresses smoking cessation (a co-factor in malignant transformation), and considers HPV vaccination in the eligible. Document the plan in writing — missed SCC in long-standing LS is a recognised cause of litigation, and a clear surveillance record is the standard of care.[1][4][5]

Acute scenarios — the five that cannot wait

LS is a chronic disease, but five presentations are urgent. Know each, and know the first move.[1][4]

1. Acute urinary retention in BXO with meatal stenosis — try gentle urethral catheterisation; if the meatus will not admit a small Foley, do not force it (false passage). Place a suprapubic catheter, treat any UTI, and arrange urgent urology for meatotomy or circumcision; start clobetasol once the acute episode settles.[1][3][8]
2. Severe erosive or ulcerated LS with secondary infection — swab for bacteria and candida, potassium permanganate 1 in 10 000 soaks or saline compresses, empirical flucloxacillin per local protocol with fluconazole 150 mg stat if candidiasis is suspected, barrier zinc oxide paste until the inflammation settles, then clobetasol induction.[1][4]
3. Suspected SCC arising in LS — urgent 4-mm punch biopsy; stage with groin ultrasound and MRI pelvis; refer to the gynaecological or penile oncology MDT; wide local excision (vulvectomy or glansectomy) with margin assessment, inguinal node dissection for high-risk disease.[1][4][5]
4. Severe vulvodynia or sexual dysfunction — treat the inflammation with clobetasol, add topical lidocaine 2-5% ointment, consider oral amitriptyline 10-25 mg at night (escalate to 75 mg) or gabapentin 300 mg three times daily for neuropathic pain, psychosexual counselling and vaginal dilators once inflammation is controlled.[1]
5. Severe constipation in prepubertal LS — treat the LS with clobetasol so the anal fissure heals, add osmotic laxatives (lactulose or polyethylene glycol 3350) and stool softeners, ensure fluids and fibre, and address parental anxiety about the bleeding.[1]

Refractory disease — when topical is not enough

A minority need systemic therapy; recognise them and escalate. Options for hyperkeratotic, scarring or steroid-refractory LS include oral oxytetracycline (anti-MMP effect), low-dose methotrexate, oral acitretin for hyperkeratotic disease, and phototherapy for extragenital or refractory genital LS. Each carries its own monitoring and contraindication load — methotrexate and acitretin are teratogenic, retinoids demand a three-year post-stop contraceptive washout, and PUVA has fallen from favour for its photocarcinogenesis. JAK inhibitors are emerging in case reports but are not yet standard of care.[1][4]

[1] [1] [1] [1]

The mantra, and the five errors to refuse

The mantra: potent steroids treat LS, surveillance is for life, and surgery is for plumbing. Below are the five errors that account for almost all avoidable harm in this disease.[1][4]

[1]

Special situations

• Pregnancy — clobetasol is safe in small amounts; maintenance usually continues; vaginal delivery is possible if the introitus is patent, caesarean reserved for severe vulvovaginal involvement; post-partum flare is common, so reinstitute clobetasol promptly.[1]
• Elderly — comorbidities, polypharmacy and hand or visual impairment may limit self-application; consider a carer or district nurse; twice-weekly maintenance is usually well tolerated; keep a higher index of suspicion for SCC.[1]
• Immunocompromised (HIV, transplant) — higher prevalence, more severe disease, higher malignant risk; favour annual over biennial surveillance; biopsy atypical lesions early; consider HPV vaccination.[1]
• Anticoagulated patients — bruising and purpura are accentuated by warfarin, DOACs or heparin, and fissure bleeding is common; clobetasol is safe; consider short tranexamic acid courses for acute bleeding.[1]

Prognosis

[1]

Good prognostic markers are early presentation, treatment adherence, smoking cessation, no architectural change at first visit and no dVIN; poor markers are late presentation, scarring at first visit, non-adherence, smoking, immunosuppression, dVIN and chronic HPV co-infection. Plan discharge in writing with the maintenance dose, emollient use, monthly self-examination and the indications for urgent re-referral — but do not discharge from surveillance, because the lifetime SCC risk never expires.[1][4]

Ward-round test

Stem 1. A 68-year-old post-menopausal woman has a figure-of-eight of ivory-white, crinkled vulvar skin with petechial purpura inside the plaques and near-complete resorption of the labia minora. What is the diagnosis, and what is the first-line drug and its regimen?[1][4]

Answer

Lichen sclerosus. The intra-plaque purpura on cigarette-paper plaques in a figure-of-eight is pathognomonic. First-line is clobetasol propionate 0.05% ointment, once daily at night for 4 weeks, then alternate nights for 4 weeks, then twice weekly for 4 weeks, then twice weekly for life. Add bland emollients and a soap substitute, and arrange annual or biennial SCC surveillance.[1][4]

Stem 2. A 35-year-old man presents with progressive phimosis and a white sclerotic ring at the coronal sulcus; the foreskin will not retract. Name the diagnosis, the diagnostic-therapeutic surgical duo, and the caveat about cure.[3][8]

Answer

Balanitis xerotica obliterans (BXO) — male genital lichen sclerosus. The duo is circumcision and biopsy. Caveat: circumcision treats the phimosis but does not cure the disease — LS can recur in the circumcision scar (Koebner), so clobetasol and annual penile SCC surveillance continue. The 2026 BASHH balanoposthitis guideline frames the management.[8][12]

Stem 3. A 6-year-old girl has perianal bleeding, fissuring and constipation, and ivory-white atrophic plaques in a figure-of-eight. What is the most consequential differential, and what is the only safe stance?[9]

Answer

Sexual abuse is the most consequential differential — the perianal bruising, fissuring and bleeding of prepubertal LS can be indistinguishable from abuse on inspection. The only safe stance is "both, until proven otherwise", with biopsy, photography and a multidisciplinary assessment (paediatric dermatology, gynaecology, safeguarding). Up to 50-75% remit at puberty; the rest need lifelong surveillance. Note that the two are not mutually exclusive — friction from abuse can itself trigger LS.[9]

Stem 4. A long-standing vulvar LS plaque develops a firm nodule that has not healed after 8 weeks of clobetasol. What do you do today, and what is the staging sequence if it is positive?[1][4]

Answer

Biopsy today — a new lump or non-healing ulcer in an LS plaque is SCC until proven otherwise (4-mm punch of the most abnormal area). If positive, stage with groin ultrasound and MRI pelvis, and refer to the gynaecological or penile oncology MDT; wide local excision with margin assessment, inguinal node dissection for high-risk disease. This is the 2-5% lifetime risk materialising — the reason surveillance is for life.[1][4]

Stem 5. A candidate writes "start hydrocortisone 1% for mild vulvar LS". Correct them, and explain why.[1][4]

Answer

Wrong drug and wrong class. Mild steroids do not control LS — the "potent steroid is dangerous on thin skin" rule does not apply here because the disease is already atrophic (the atrophy paradox), and under-treatment allows scarring and may raise SCC risk. First-line is clobetasol propionate 0.05% ointment on the 12-week taper, then twice-weekly lifelong maintenance — not hydrocortisone.[1][4]

Stem 6. Draw the LS histology and name the band the infiltrate sits in. Why does that band matter?[1][3]

Answer

The RED-WHITE-BLUE pattern: red atrophic epidermis with basal vacuolar degeneration, white hyalinised papillary dermis with loss of elastic fibres, blue band-like lymphocytic infiltrate in the mid-dermis below the hyalinised zone. It matters because in lichen planus the infiltrate sits at the interface, not below a hyalinised band — that single band is the histological discriminator between LS and LP. DIF is negative in LS.[1][3]

References

1. [1]De Luca DA, Papara C, Vorobyev A, et al. Lichen sclerosus: The 2023 update Front Med (Lausanne), 2023.PMID 36873861
2. [2]Arif T, Fatima R, Sami M. Extragenital lichen sclerosus: A comprehensive review Australas J Dermatol, 2022.PMID 35950883
3. [3]Fergus KB, Lee AW, Baradaran N, et al. Pathophysiology, Clinical Manifestations, and Treatment of Lichen Sclerosus: A Systematic Review Urology, 2020.PMID 31605681
4. [4]Kirtschig G, Kinberger M, Kreuter A, et al. EuroGuiderm guideline on lichen sclerosus-Treatment of lichen sclerosus J Eur Acad Dermatol Venereol, 2024.PMID 38822598
5. [5]Krapf JM, Mitchell L, Holton MA, et al. Vulvar Lichen Sclerosus: Current Perspectives Int J Womens Health, 2020.PMID 32021489
6. [6]Patsatsi A, Kyriakou A, Mantas A, et al. Circulating anti-BP180 NC16a and anti-BP230 autoantibodies in patients with genital lichen sclerosus do not correlate with disease activity and pruritus Acta Derm Venereol, 2014.PMID 24676719
7. [7]Soliman SH, Bosseila M, Hegab DS, et al. Evaluation of diagnostic accuracy of dermoscopy in some common hypopigmented skin diseases Arch Dermatol Res, 2024.PMID 39177715
8. [8]Fox W, McKenna PH Treatment algorithm for the comprehensive management of severe lichen sclerosus in boys based on the pathophysiology of the disease J Pediatr Urol, 2024.PMID 38918118
9. [9]Savage A, Miao VY, Fischer G, et al. Long-Term Outcomes of Prepubertal-Onset Vulvar Lichen Sclerosus Pediatr Dermatol, 2026.PMID 41084133
10. [10]Patel B, Lala A, Verdolini R Topical Tacrolimus for Lichen Sclerosus: Systematic Review of Efficacy and Safety Dermatol Pract Concept, 2026.PMID 41912210
11. [11]Day T, Scurry J, Parra-Herran C, et al. 2026 International Society for the Study of Vulvovaginal Disease terminology for vulvar intraepithelial neoplasia and squamous intraepithelial lesions Am J Obstet Gynecol, 2026.PMID 42214713
12. [12]Edwards SK, Shashidharan P, Fernando I, et al. BASHH national guideline on the management of balanoposthitis (and related penile skin conditions) 2026 Int J STD AIDS, 2026.PMID 42216889