Synopsis
Recognise cutaneous, mucosal, scalp, nail and pigmentary lichen planus, confirm atypical disease safely, protect scarring sites, and monitor persistent lesions for malignant change.
- Classic cutaneous lichen planus is an itchy eruption of flat-topped shiny papules, often violaceous or darker than surrounding skin, with fine pale Wickham striae on wrists, ankles and lower back.
- Examine mouth, genital skin, scalp and nails with explanation and consent: specialised-site disease can scar even when the ordinary skin eruption is modest.
- In darker skin, papules may be deep brown or subtly purple, pale striae remain useful, and grey-brown post-inflammatory pigment can persist long after active inflammation.
- Lichen planus is usually diagnosed clinically; biopsy a representative lesion when diagnosis is uncertain and promptly sample any persistent indurated, ulcerated or enlarging focus.
- Asymptomatic limited skin disease can be observed. Symptomatic cutaneous disease usually starts with a potent or very potent topical corticosteroid applied carefully once daily under BAD guidance.
- Face, flexures and long-term mucosal use need specialist-selected steroid-sparing or site-specific formulations; much lichen-planus prescribing is off-label and should be stated as such.
- Scalp follicular loss, rapidly progressive nail change and erosive oral or genital disease merit early specialist referral because permanent damage and low malignant risk alter monitoring.
- Avoid scratching and use emollient for itch, while warning that product residue on fabric and hair increases fire severity even when dry.
Key red flags
A persistent indurated, ulcerated, bleeding or enlarging lesion within oral, genital or hypertrophic disease needs urgent biopsy assessment for squamous cell carcinoma.
Scalp inflammation with perifollicular scale and loss of follicular openings can cause permanent scarring alopecia and warrants expedited dermatology review.
Rapid nail thinning, pterygium or destruction may become irreversible, so progressive nail-unit disease needs early specialist treatment.
Painful vulvovaginal erosion, discharge, narrowing or adhesions, or penile scarring and phimosis requires specialist genital examination with consent and appropriate multidisciplinary care.
Odynophagia, dysphagia, weight loss or food impaction can indicate oesophageal involvement or malignancy and needs prompt upper-gastrointestinal assessment.
Reticular white lacy lines may be asymptomatic, while erosive gingival or buccal disease is painful and affects eating. Examine the full mouth and palpate persistent ulcerated or indurated areas.
Glazed painful erythema, white border, erosion and scarring may affect vulva, vagina, glans or foreskin. Use trauma-informed consent, offer a chaperone and avoid assuming infection or sexual transmission.
Perifollicular scale, erythema and loss of follicular openings indicate lichen planopilaris and active scarring alopecia. Symptoms can include itch, tenderness or burning before visible loss is extensive.
Investigation priorities
Map cutaneous, oral, genital, scalp and nail involvement and identify sites at risk of scarring or cancer.
Management branches
Typical skin papules without scarring-site disease, significant erosion or malignant warning features.
- Explain the often self-limiting course, avoid skin injury, use emollient or soap substitute for comfort, and document active papules separately from residual pigment.
- Observe asymptomatic limited disease; for itch or active inflammation, apply a prescribed potent or very potent topical corticosteroid carefully once daily to papules.
- Review within the defined course for flattening, itch, atrophy and diagnostic fit; stop active steroid when lesions become flat pigment rather than continuing to chase colour.
- Refer widespread, persistent or treatment-resistant disease for phototherapy or systemic options selected by dermatology.