ConditionSkin, hair & nails
Lichen Planus
Lichen planus is a chronic inflammatory condition in which the immune system attacks cells of the skin and mucous membranes. On the skin it causes itchy, flat-topped, purple or violet bumps, often on the wrists, ankles and lower back. In the mouth it causes lacy white lines and sometimes painful red sores. It can also affect the genitals, scalp and nails. It is not contagious. Skin lichen planus often clears within 1 to 2 years, while oral and genital forms tend to last longer. Steroid treatments control most symptoms.
Also called: LP, oral lichen planus, cutaneous lichen planus, erosive lichen planus
At a glance
- What it is
- A T-cell-driven inflammatory condition of skin and mucous membranes.
- Skin
- Itchy, flat, shiny, purple bumps with fine white lines (Wickham striae).
- Mouth
- Lacy white patches, redness and painful erosions, often on the inner cheeks.
- Other sites
- Genitals, scalp (scarring hair loss), nails, esophagus, eyes (rare).
- Treatment
- Topical or injected steroids, antihistamines for itch, and systemic treatments for severe cases.
When to get help
See a doctor within a day or two
- Painful sores in the mouth or genitals that stop you eating, drinking or passing urine
- Difficulty swallowing or food sticking (possible esophageal involvement)
- A rash that started within weeks of a new medicine
Book a routine appointment
- An itchy rash of purple, flat-topped bumps that lasts more than 2 weeks
- White lacy patches or sore areas in the mouth, or soreness with spicy food
- A mouth sore, lump or patch that changes, thickens or does not heal in 3 weeks
- Vulvar or vaginal pain, burning or pain with sex
- Patchy hair loss with redness around follicles, or thinning, ridged nails
- Known oral lichen planus: regular dental or oral medicine checks
Usually safe to manage at home
- Mild itch from known skin lichen planus that improves with moisturizers and prescribed creams
What lichen planus looks like
Skin (cutaneous) lichen planus
The classic description is the "6 Ps": purple, polygonal, planar (flat-topped), pruritic (itchy) papules and plaques. Bumps are shiny and may have fine white lines on the surface called Wickham striae. Common sites:
- inner wrists and forearms
- ankles and shins
- lower back
- genitals
New lesions can appear along scratches or injuries (the Koebner phenomenon). As lesions heal, they often leave dark brown marks, especially on darker skin, which fade over months. Thick (hypertrophic) lichen planus on the shins can be very itchy and persistent.
Oral lichen planus
The mouth is affected in about half of people with lichen planus, and some have only oral disease.
- Reticular: lacy white lines, often on the inner cheeks, usually painless
- Erosive or atrophic: red, raw or ulcerated areas that sting, especially with spicy, acidic or hot foods
- Desquamative gingivitis: red, peeling gums
Other sites
- Genital: white streaks or painful erosions on the vulva, vagina or penis. Vulvovaginal-gingival syndrome affects the vulva, vagina and gums together and can cause scarring
- Scalp (lichen planopilaris): redness and scaling around hair follicles leading to permanent, scarring hair loss
- Nails: thinning, ridging, splitting, and sometimes nail loss
- Esophagus and eyes: rare, causing difficulty swallowing or eye irritation
Causes and triggers
Lichen planus is caused by the immune system's T cells attacking the basal cells of the skin or mucosa. The trigger is often unknown. Associations and triggers include:
- Hepatitis C infection: linked in some populations. Testing may be recommended
- Medicines: some blood pressure medicines (beta blockers, ACE inhibitors), NSAIDs, antimalarials, gold, and some newer cancer drugs can cause a similar lichenoid drug eruption
- Dental materials: contact with amalgam fillings can cause lichenoid reactions in the adjacent cheek
- Stress may trigger flares
- Genetic predisposition
It is not contagious and not caused by an infection you can pass on.
Diagnosis
A dermatologist or oral medicine specialist can often diagnose lichen planus by its appearance. A small biopsy confirms it, especially for mouth, genital or scalp disease, or when cancer must be excluded. Blood tests may check for hepatitis C. A patch test may be suggested if a dental material reaction is suspected.
Lichen planus vs similar conditions
| Condition | Key differences |
|---|---|
| Lichen sclerosus | Thin, white, crinkled skin, mainly genital, rarely affects the mouth |
| Psoriasis | Thicker, silvery scale, elbows, knees and scalp |
| Eczema | Ill-defined, often weeping or dry patches |
| Oral thrush | White patches that wipe off |
| Leukoplakia | White patch that cannot be wiped off and lacks the lacy pattern, needs biopsy |
Treatment
There is no cure, but symptoms can be controlled. Mild disease without symptoms may need no treatment.
Skin
- Topical corticosteroids: potent creams or ointments are first-line.
- Steroid injections into thick plaques.
- Antihistamines for itch, and moisturizers.
- Phototherapy (narrowband UVB) for widespread disease.
- Oral treatments for severe disease: short courses of oral steroids, acitretin, methotrexate or other immune-modulating medicines.
Mouth
- Topical steroids as gels, mouthwashes or pastes.
- Topical calcineurin inhibitors (tacrolimus) in some cases.
- Good oral hygiene and regular dental care, which reduce flares from plaque and gum inflammation.
- Avoid triggers: spicy, acidic and crunchy foods, alcohol, tobacco, and toothpastes with sodium lauryl sulfate.
- Check for and treat oral thrush, which can occur with steroid use.
Genital
- Potent topical steroid ointments, vaginal steroid preparations, and dilators to prevent scarring, under specialist care.
Complications and outlook
- Skin lichen planus usually resolves within 1 to 2 years, though it can recur
- Oral and genital lichen planus are often long-lasting, with flares and remissions
- Dark marks after healing
- Scarring and narrowing in the vagina, permanent hair loss on the scalp, and nail loss
- Cancer risk: long-standing erosive oral and genital lichen planus carries a small increased risk of squamous cell carcinoma. Regular checks with a dentist, oral medicine specialist or gynecologist, and prompt review of any new lump or non-healing sore, are recommended. Avoid smoking and limit alcohol.
Frequently asked questions
What causes lichen planus?
Lichen planus is caused by the immune system attacking cells of the skin or mucous membranes. The trigger is often unknown, but it has been linked to hepatitis C, certain medicines, dental materials and stress. It is not contagious and is not caused by poor hygiene.
Is lichen planus contagious?
No. Lichen planus cannot be passed to other people through touch, kissing or sexual contact. It is an immune-related condition, not an infection.
What does oral lichen planus look like?
Oral lichen planus most often appears as lacy white lines on the inner cheeks, sometimes with red, raw or ulcerated areas that sting with spicy or acidic food. It can also cause red, peeling gums. A biopsy may be needed to confirm it.
How long does lichen planus last?
Skin lichen planus often clears within 1 to 2 years, though dark marks may remain longer. Oral and genital lichen planus tend to last many years, with periods of flares and improvement. Treatment can control symptoms during flares.
Can lichen planus turn into cancer?
Skin lichen planus rarely does. Long-standing oral and genital lichen planus, especially the erosive type, carry a small increased risk of squamous cell carcinoma. Regular checkups and prompt attention to any lump, thickening or non-healing sore are recommended.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Dermatology: Lichen planus, overview and treatment
- MedlinePlus: Lichen planus
- NHS: Lichen planus
- British Association of Dermatologists: Lichen planus patient information
- American Academy of Oral Medicine: Oral lichen planus