Lichen simplex chronicus

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Diagnosis rests on morphology plus behaviour. The plaque is poorly or sharply bounded, thickened, excoriated and deeply lined; colour may be pink, violaceous, brown, grey or lighter. Ask where and when scratching occurs, including sleep, and whether sensation preceded visible skin change.

Successful care treats both entry and maintenance. Remove contact or fungal causes, reduce venous or xerotic itch, then interrupt rubbing. A potent body-site steroid may be needed for thick plaque, but genital, facial and fold skin need different potency and specialist oversight. Occlusion increases delivery and risk and should not be improvised.

Lichen simplex chronicus care should combine visible inflammation with itch, pain, sleep, occupation and treatment burden. Agree where each product goes, how much is used and when response will be reviewed; explain urgent features separately so normal fluctuation is not confused with infection or treatment failure.

Key points

Lichen simplex is a thick leathery plaque with exaggerated skin markings caused and maintained by repeated rubbing or scratching.
Common accessible sites include nape, forearms, ankles, lower legs, scalp and anogenital skin; one person may have several plaques.
Find the itch source: eczema, contact allergy, tinea, scabies, venous disease, neuropathy and systemic pruritus may initiate the cycle.
Break scratching with explanation, nail care, night barriers, emollient and a short adequately potent topical corticosteroid matched to site.
Address stress and automatic behaviour respectfully; behavioural techniques complement physical treatment and do not imply the itch is imagined.
Biopsy a persistent atypical, ulcerated or indurated plaque and sample a fungal edge when tinea remains plausible.
For Lichen simplex chronicus, document body sites, severity, sleep and function, recent treatment, infection features and what the patient can realistically apply each day.
In Lichen simplex chronicus, reassess the diagnosis when a well-used, correctly potent regimen fails rather than repeatedly intensifying treatment without examining adherence, exposure and mimics.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Underlying pruritic dermatosis

Atopic, contact, venous, psoriatic, fungal and infestational disease can initiate repeated scratching at one accessible site.

Neuropathic and systemic itch

Nerve injury, radiculopathy, renal, hepatic, haematological or endocrine disease can create focal or generalised itch without an obvious primary eruption.

Habit and stress amplification

Stress, boredom, sleep disturbance and learned automatic rubbing maintain the behaviour after the original trigger has partly settled.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Mechanical epidermal thickening
Repeated rubbing accelerates epidermal turnover and hyperkeratosis, progressively exaggerating normal skin lines into a thick leathery plaque.
2
Neural sensitisation
Chronic inflammation lowers itch thresholds and scratching briefly inhibits the unpleasant sensation, reinforcing a self-perpetuating behavioural reward cycle.
3
Barrier disruption
Excoriation, fissuring and repeated topical-product overuse impair the epidermal barrier, permitting irritants and allergens to intensify local inflammation.
4
Pigment alteration
Sustained inflammation and trauma produce darker or lighter colour and excoriation marks, often prominent in deeply pigmented skin.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Lichenified architecture

A leathery plaque has exaggerated criss-cross skin markings, scale and excoriations at an easily reached site.

Behavioural timing

Rubbing during concentration, stress or sleep may be partly automatic and continues after transient relief.

Anogenital phenotype

Chronic vulval, scrotal or perianal itch can produce thickening and fissures but requires consented examination for primary disease.

Neuropathic clue

Focal itch or rubbing in one dermatome with altered sensation and little preceding rash suggests nerve-related initiation.

Atypical tumour warningRed flag

Progressive induration, ulceration, bleeding or non-response despite verified treatment requires biopsy assessment.

Red flags requiring action

Non-healing ulcer, bleeding induration, widespread severe pruritus with systemic symptoms, genital scarring, neuropathic deficit, child safeguarding concern or treatment-resistant focal disease requires specialist evaluation.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Full skin, nail and mucosal examinationFirst step
Why
Identify the primary itch disorder and other plaques beyond the presenting site.
Interpretation and limitations
Examine with consent, including feet for fungus and lower legs for venous change; scratching may erase the initiating morphology.
02
Skin scraping from a plausible edge
Why
Exclude dermatophyte infection before further potent corticosteroid.
Interpretation and limitations
Sample active untreated scale; negative testing loses value after steroid or antifungal exposure.
03
Patch testing for exposure-linked disease
Why
Find allergic contact dermatitis from products, dressings or occupational chemicals.
Interpretation and limitations
Positive sensitisation is useful only when a product and anatomical distribution establish current relevance.
04
Pruritus-directed blood tests
Why
Assess renal, hepatic, thyroid, iron or haematological disease when itch is generalised or systemic clues exist.
Interpretation and limitations
Testing should be selected from history and examination; one focal lichenified plaque rarely justifies an indiscriminate panel.
05
Skin biopsy of persistent atypical plaque
Why
Exclude hypertrophic lichen planus, lymphoma or carcinoma.
Interpretation and limitations
Choose an indurated active area and communicate duration, symptoms, failed treatment and differential.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Hypertrophic lichen planus

Very itchy thick lower-leg plaques can resemble lichen simplex but may have violaceous borders, Wickham striae or disease at other mucocutaneous sites.

Chronic dermatophyte infection

An active edge, asymmetry and foot or nail fungus supports tinea incognito, especially after corticosteroid exposure.

Cutaneous lymphoma or carcinoma

A persistent enlarging, infiltrated, ulcerated or treatment-resistant plaque warrants timely biopsy rather than continued attribution to habitual scratching.

Nodular prurigo

Multiple firm excoriated nodules across accessible limbs indicate a broader chronic prurigo phenotype and may require systemic itch assessment.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Typical focal plaqueInterrupt the itch-scratch cycleFirst stepA stable accessible lichenified plaque lacks infection, tumour features or a clear untreated mimic.

1Explain the reinforcement cycle, agree a non-shaming strategy such as short nails, covering at night and substituting pressure or cooling for scratching.
2Apply a potent topical corticosteroid thinly for a defined short course and use generous emollient to reduce dryness and friction.
3Review itch, thickness and actual scratching triggers within two to four weeks, then step down anti-inflammatory exposure.

02Find and treat the driverResolve underlying itchDistribution, exposure, fungus, venous disease, neuropathy or systemic symptoms suggest a primary cause.

1Take targeted mycology, patch testing or blood investigations and treat the identified dermatological or systemic disorder.
2EscalationFor neuropathic features, examine sensation and relevant neurology and avoid repeated corticosteroid escalation when skin inflammation is secondary.
3Coordinate psychological or behavioural support when stress, compulsive rubbing or sleep disturbance remains a major amplifier.

03Atypical or refractory plaqueObtain tissue and specialist reviewVerified adequate treatment fails or the plaque enlarges, ulcerates, bleeds or becomes deeply indurated.

1Stop assuming non-adherence and refer dermatology for biopsy from a representative active area.
2Reassess lichen planus, tinea incognito, nodular prurigo, lymphoma and squamous malignancy using clinical and pathological findings.
3Continue gentle barrier care and symptom support without masking the lesion with indefinite very-potent corticosteroid.

Key medicines and prescribing safety2 treatments · regimens, roles and cautions

A potent topical corticosteroid that helps interrupt inflammatory itch in established lichen simplex when infection and mimics have been considered.

Betamethasone valerate 0.1% cream

Apply thinly to an active body-site plaque once or twice daily for up to four weeks, then reduce or stop as skin flattens and itch settles.

Avoid face, genitals, folds, infection and unplanned occlusion; monitor atrophy and systemic exposure and biopsy rather than extending ineffective use.

A very potent option for selected hyperkeratotic lichenified sites when a safer potency has failed and diagnosis is secure.

Clobetasol propionate 0.05% ointment

Adults apply thinly once or twice daily only to severe resistant thick plaques under specialist direction, not exceeding four weeks or 50 g weekly.

Never use on thin anogenital or facial skin without specialist instruction; avoid untreated infection and prolonged occlusion and step down as soon as control permits.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Secondary infection

Repeated excoriation permits impetiginisation and cellulitis, creating increasing pain, crust, pustules or systemic illness beyond ordinary itch.

Scarring and pigment change

Long-standing rubbing can leave permanent thickening, alopecia and hyperpigmentation or hypopigmentation even when itch control improves.

Sleep and mental-health burden

Automatic nocturnal scratching disrupts sleep and may interact with anxiety, low mood or compulsive behaviour without making symptoms imaginary.

Diagnostic delay

Assuming all thick plaques are self-induced can postpone diagnosis of tinea, lichen planus, neuropathy, lymphoma or squamous malignancy.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Track scratch episodes, nocturnal waking, plaque thickness, fissuring and trigger situations rather than asking only whether itch is better.
Measure and photograph an atypical solitary plaque with consent so enlargement or ulceration is not missed.
Review corticosteroid quantity and site carefully and separate residual pigment from ongoing lichenification.
At review of Lichen simplex chronicus, compare itch, sleep, fissuring or ooze, affected sites, function and treatment use with the agreed baseline.
For Lichen simplex chronicus, record adverse effects, new contact exposures and the safety-net for pain, fever, rapidly spreading disease, eye symptoms or systemic illness.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

The plaque is an effect

Lichenification records repeated mechanical stimulation and should prompt the question of what made the patient scratch first.

Relief reinforces rubbing

Scratching briefly suppresses itch through competing sensory input, making the behaviour biologically understandable rather than a failure of willpower.

Accessible sites are clues

The nape, ankle and forearm can be repeatedly reached, while an inaccessible plaque should broaden the differential.

Pigment can remain

A flattened symptom-free dark or light patch may represent resolved inflammation and does not need continued potent steroid.

Occlusion changes potency

Covering a steroid-treated plaque markedly increases absorption and adverse-effect risk and requires explicit supervision.

11Common pitfallsFrequent interpretation and management errors.

01
Telling the patient simply to stop scratching without treating itch and automatic behaviour.
02
Using potent steroid on genital skin according to a limb regimen.
03
Missing tinea incognito after corticosteroid has reduced scale at the active edge.
04
Assuming a growing ulcerated plaque is behavioural and postponing biopsy.
05
Ordering broad systemic tests for one straightforward plaque while omitting a complete skin examination.