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# Lichen planus

Lichen planus is an immune skin condition with itchy, flat, purple bumps on the wrists and ankles. It can also affect the mouth, genitals and nails.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Skin](https://durgical.com/en/anatomy/skin/)
- [Gums (gingiva)](https://durgical.com/en/anatomy/gums/)
- [Tongue](https://durgical.com/en/anatomy/tongue/)

## Why it happens

- [Apoptosis: the intrinsic and extrinsic pathways](https://durgical.com/en/general-pathology/apoptosis-the-intrinsic-and-extrinsic-pathways/)
- [Skin: epidermis layers, dermis, hypodermis](https://durgical.com/en/histology/skin-epidermis-layers-dermis-hypodermis/)
- [Basement membrane](https://durgical.com/en/histology/basement-membrane/)

## What it is

A chronic, T cell–mediated inflammatory disease of the skin, mucous membranes, hair and nails. Skin lesions are the classic purple, polygonal, pruritic, flat-topped papules; oral lichen planus shows white lacy (reticular) streaks.

## Who gets it

Affects about 1% of adults, mostly aged 30–60. Oral lichen planus is more common in women. An association with hepatitis C virus infection has been reported, varying by region.

## Causes

- Cytotoxic T cells attacking basal keratinocytes, likely against an altered self-antigen
- Hepatitis C virus infection is associated in some populations
- Lichenoid drug eruptions: beta-blockers, ACE inhibitors, thiazides, antimalarials, gold, NSAIDs
- Contact with dental amalgam in some oral lesions

## Risk factors

- Middle age
- Hepatitis C infection
- Exposure to culprit drugs
- Other autoimmune diseases

## Pathophysiology

CD8+ T cells accumulate at the dermo-epidermal junction and trigger apoptosis of basal keratinocytes. Histology shows a band-like lymphocytic infiltrate, saw-tooth rete ridges, hypergranulosis and colloid (Civatte) bodies. The thickened granular layer produces the white Wickham striae.

## Classification

- Cutaneous (classic, hypertrophic, annular, linear, bullous)
- Oral (reticular, erosive, atrophic, plaque-like)
- Genital (vulvovaginal-gingival syndrome), nail and scalp (lichen planopilaris) forms
- Lichenoid drug eruption

## Symptoms and signs

- The six Ps: purple, polygonal, pruritic, planar (flat-topped) papules and plaques
- Fine white lines on the surface (Wickham striae)
- Typical sites: flexor wrists, forearms, ankles, shins, lower back
- New lesions along scratch lines (Koebner phenomenon)
- Oral: white lacy streaks on the buccal mucosa, gums or [tongue](https://durgical.com/en/anatomy/tongue/); painful erosions in erosive forms
- Nails: thinning, ridging, pterygium; scalp: scarring hair loss

## Red flags

- Non-healing ulcer, induration or a lump in oral or genital lesions (possible squamous cell carcinoma)
- Painful erosions limiting eating or drinking
- Vaginal scarring and stenosis or painful intercourse
- Signs of [liver](https://durgical.com/en/anatomy/liver/) disease such as jaundice

## Diagnosis

**Clinical**
Clinical recognition of the six Ps and Wickham striae; examine mouth, genitals, nails and scalp. Review medication history for lichenoid drug eruption.

**Tests**
[Skin](https://durgical.com/en/anatomy/skin/) or mucosal biopsy (band-like lymphocytic infiltrate at the dermo-epidermal junction, Civatte bodies); direct immunofluorescence in uncertain cases. Hepatitis C serology is commonly checked.

**Imaging**
Not needed. Dermoscopy shows Wickham striae clearly.

## Differential diagnosis

- Psoriasis (silvery scale, extensor surfaces)
- Lichenoid drug eruption
- Discoid lupus erythematosus
- Oral candidiasis and leukoplakia (oral lesions)
- Lichen sclerosus (genital lesions); secondary syphilis

## Goal of treatment

Relieve itch and pain, speed resolution of skin lesions, control mucosal disease, and monitor oral and genital lesions for cancer; stop any culprit drug.

## Treatment

**Medical**
High-potency topical corticosteroids are first-line for skin lesions; topical corticosteroids or calcineurin inhibitors for oral lesions.

**Medical**
Antihistamines for itch; intralesional corticosteroids for hypertrophic lesions.

**Medical**
Widespread or resistant disease: systemic corticosteroids for short periods, acitretin, methotrexate or other immunosuppressants.

**Procedure**
Narrowband UVB phototherapy for extensive cutaneous disease.

**Follow-up**
Regular review of oral and genital lesions for malignant change; good oral hygiene and dental care; avoid tobacco and alcohol.

## Complications

- Post-inflammatory hyperpigmentation, prominent in darker skin
- Squamous cell carcinoma in chronic erosive oral or genital lesions
- Scarring alopecia and permanent nail loss
- Vulvovaginal or oesophageal stenosis

## Prognosis

Cutaneous lichen planus usually resolves within 1–2 years, often leaving pigmentation. Oral and genital forms are chronic and relapsing and need long-term follow-up because of the small cancer risk.

## Test yourself

Think of the answer, then tap the question to see it.

## What are the six Ps of lichen planus?

Purple, polygonal, pruritic, planar (flat-topped) papules and plaques.

## What are Wickham striae?

Fine white lacy lines on the surface of lichen planus lesions, also seen in the mouth.

## Which viral infection is associated with lichen planus?

Hepatitis C virus infection.

## What is the typical histology of lichen planus?

A band-like lymphocytic infiltrate at the dermo-epidermal junction with saw-tooth rete ridges and Civatte bodies.

## Which malignancy can develop in chronic erosive oral lichen planus?

Oral squamous cell carcinoma.

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## Related conditions

- [Viral hepatitis](https://durgical.com/en/conditions/viral-hepatitis/)
- [Psoriasis](https://durgical.com/en/conditions/psoriasis/)
- [Discoid lupus erythematosus](https://durgical.com/en/conditions/discoid-lupus-erythematosus/)
- [Head and neck squamous cell carcinoma (oral cavity and oropharynx, HPV)](https://durgical.com/en/conditions/head-and-neck-squamous-cell-carcinoma/)
- [Vulvar lichen sclerosus and vulvar cancer](https://durgical.com/en/conditions/vulvar-lichen-sclerosus-and-vulvar-cancer/)
- [Cutaneous and mucocutaneous candidiasis](https://durgical.com/en/conditions/cutaneous-and-mucocutaneous-candidiasis/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Lichen planus](https://medlineplus.gov/ency/article/000867.htm) (MedlinePlus, US National Library of Medicine, 2026).

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Source: https://durgical.com/en/conditions/lichen-planus/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/lichen-planus/