Lichen planus

1 - ACKNOWLEDGEMENTS

Chapter written with the help of the EADV, the Fondation René Touraine and the Therapeutics in Dermatology

2 - OVERVIEW

Lichen

planus (LP) is a relatively common, chronic, inflammatory disease, that can affect the skin, mucosal membranes (mouth and genitals), scalp and nails. It can affect any person at any age, but usually occurs in middle adulthood (>40 years).

Dermatologists can diagnose LP clinically, by performing a complete skin examination. Sometimes, a skin biopsy can be performed to confirm the diagnosis.

LP that affects the skin often resolves spontaneously within 2 years, although it can sometimes recur. Mucosal LP is more likely to persist for several years, and scarring can be persistent. LP affecting the scalp can lead to patches of permanent baldness. Rarely, longstanding erosive LP in the mouth or in the genitals can be a risk factor for cancer development at the affected sites.

3 - SYMPTOMS

There are several clinical types of LP, with different manifestations, depending on the affected area(s):

• Skin:

Cutaneous LP usually presents as small, raised skin bumps, that are firm, flat-topped, shiny and red / purple / brownish in color, sometimes showing thin white lines. These skin lesions are usually very itchy, but can be asymptomatic. When the lesions are thick, they can be scaly. Blisters can rarely appear.

There can be only few or several lesions, which can appear anywhere on the skin surface, although common locations include wrists, hands, ankles and lower back.

When lesions resolve, they can leave brown / grey spots on the skin, that take months or years to fade.

• Mouth:

Oral LP can occur with or without simultaneous skin lesions elsewhere. It usually affects the inner part of the cheeks, but can also appear on the tongue, lips and gums.

Common manifestations are painless white dots and streaks that form a lace-like pattern, redness and swelling. Peeling of the gums can sometimes occur.

In the case of erosive LP, there are persistent, painful or “burning” wounds or sores, that can impair eating.

• Genitals:

In women, LP can affect the labia majora and labia minora. Vulvar LP can have several clinical manifestations, including white streaks in a lace-like pattern, painful and persistent wounds or sores (erosive LP), distortional scarring and easy bleeding, that can impair sexual intercourse and quality of life.

In men, penile LP usually presents as small bumps arranged as a ring around the glans penis. White streaks and erosive LP can also occur.

• Scalp:

When it affects the scalp, or less commonly other hairy areas of the body, it is called lichen planopilaris (LPP). LPP manifests as skin redness and irritation, with tiny, red bumps around hair follicles. Blisters can rarely appear.

As the hair follicles are destroyed, LPP leave scars that form permanent bald patches in the scalp (cicatricial alopecia).

• Nails:

LP can affect one or several nails of the fingers and/or toes, together with skin involvement or not. Sometimes it affects all of the 20 nails.

Nail LP usually presents as thin, fragile, sometimes darkened nails, with ridges or grooves. The nails can also be thicker, and there could be scars around them. The nails can stop growing and sometimes they are lost, temporarily or permanently.

4 - CAUSES

LP is a chronic, inflammatory disease, whose exact cause remains unclear. It has some features of an “autoimmune disease”, and it is neither contagious nor malignant.

Some contributing factors have been identified, including:

• Genetic predisposition
• Physical and/or emotional stress
• Skin injury or other skin diseases
• Systemic viral infections – e.g.: hepatitis C
• Contact allergy – e.g.: metal fillings in oral LP
• Some drugs – e.g.: diuretics and medicines for malaria (quinine, quinidine)

5 - TREATMENT

Treatment is not always necessary, as LP often resolves spontaneously. Also, there is no cure for this condition.

If symptoms are bothersome and/or there are many lesions, several treatments are available, that can relief itch or pain and facilitate healing. These include:

• Oral antihistamines
• Topical corticosteroids (creams or ointments applied on the affected area)
• Intralesional corticosteroid injections
• Topical calcineurin inhibitors (tacrolimus ointment; pimecrolimus cream)
• Topical retinoids
• Other systemic treatments, like oral corticosteroids (Prednisone), Acitretin, Hydroxychloroquine, Methotrexate, Azathioprine, Mycophenolate mofetil
• Phototherapy, a treatment that uses ultraviolet radiation

Skin dark spots that may persist after LP healing can be lightened with creams, lasers and other treatments by Dermatologists.

6 - TIPS FOR MANAGING

Every patient with suspected LP should see a Dermatologist for adequate diagnosis and treatment.

People suffering from cutaneous LP should try to control the itch, avoid scratching or injuring the skin, and avoid stress.

In the case of oral LP, it is also important to avoid smoking and alcohol consumption, avoid spicy, salty and/or acidic foods and drinks, brush the teeth and floss regularly, and, importantly, maintain regular medical visits with a Dermatologist and a Dentist.