Lichen Planus

What is lichen planus?

Lichen planus is an inflammatory condition. As well as the skin, it can involve the mouth lining, genital skin, scalp and nails. It is thought to occur when the immune system mistakenly attacks cells in the skin or mucous membranes.

Who gets it?

Lichen planus is uncommon. It usually appears after the age of 20, most often between 40 and 70, and is rare in children. Lichen planus of the mouth affects about 1 to 2 in 100 people, mostly women over 40.

What causes it?

The exact cause is unknown, and in many people no trigger is found. Possible triggers include viral infections, such as hepatitis B and C and some herpes viruses; metals such as mercury, copper and gold in dental fillings, which can trigger lichen planus in the mouth; certain medicines, including some used for high blood pressure, malaria, infections and depression; and stress.

Is it hereditary or contagious?

Lichen planus is not hereditary, although the tendency to develop it can occasionally run in families. It is not an infection, so it cannot be passed on, whether by kissing or by sexual contact.

What does it look and feel like?

On the skin, lichen planus causes clusters of small, flat-topped, shiny bumps, usually 1 to 3 mm across, that are pink, purple-red or violet in colour, sometimes with fine white lines across the surface known as Wickham's striae. On brown and black skin, the bumps can look dark brown or grey. They are usually very itchy. They most often appear on the inner wrists, forearms, lower back, shins and ankles, and can develop in lines where the skin has been scratched. On the lower legs, thicker, warty patches can form.

In the mouth, lichen planus commonly causes a lacy white pattern on the inside of the cheeks, which may cause no symptoms. Some people develop red, sore or ulcerated areas that sting with spicy or acidic food.

On the genitals, it can cause itchy or sore patches, white lacy areas, or raw, painful erosions, particularly on the vulva and inside the vagina. This can cause pain with sex and, over time, scarring.

On the scalp, a form called lichen planopilaris causes inflammation around the hair follicles and can lead to permanent hair loss. Nail involvement can cause thinning, ridging, splitting and, in some cases, permanent nail loss.

How is it diagnosed?

Lichen planus can often be diagnosed from its appearance. A skin biopsy may be taken to confirm the diagnosis, particularly in the mouth, genitals or scalp. Blood tests may be recommended in some cases.

What are the treatment options?

Dr Mounsey will confirm the diagnosis, which may include a small skin biopsy, and check the mouth, genital skin, scalp and nails. For genital or oral lichen planus he can draw on his interest in genital dermatology. Treatment usually involves potent steroid ointments or calcineurin inhibitor creams, with steroid mouthwashes or gels for the mouth. Widespread or stubborn lichen planus may be treated with phototherapy or tablets such as acitretin, methotrexate or a short course of oral steroids. He will also advise on soothing skin care and monitoring of long-standing genital or oral disease.

What is the outlook?

Lichen planus of the skin usually settles on its own, often within one to two years, although some people have further episodes. It frequently leaves brown or grey marks as it heals, particularly on brown and black skin, and these can take many months to fade.

Lichen planus of the scalp, nails, mouth and genitals tends to last longer and can persist for years. Lichen planus of the mouth carries a small risk of mouth cancer, about 1 in 100 over ten years, so regular dental checks are important, and any persistent ulcer, lump or thickened area in the mouth or genitals should be checked.

More information

British Association of Dermatologists patient leaflet: https://www.bad.org.uk/pils/lichen-planus

British Association of Dermatologists patient leaflet on oral lichen planus: https://www.bad.org.uk/pils/oral-lichen-planus

This page gives general information only and is not a substitute for a consultation. Everyone's skin is different, and what is right for you will depend on your own circumstances. If you are worried about a skin problem, please book an appointment with Dr Mounsey or speak to your GP. If you have a mole or skin lesion that is changing, bleeding or growing quickly, please seek medical advice promptly.