Lichen Planus

Lichen planus is an inflammatory condition that can affect the skin, hair, nails and mucous membranes. On the skin, lichen planus usually appears as purplish, often itchy, flat-topped bumps, developing over several weeks. In the mouth, vagina and other areas covered by a mucous membrane, lichen planus forms lacy white patches, sometimes with painful sores.

Contributing factors

Contributing factors to lichen planus may include:

• Genetic predisposition
• Physical and emotional stress
• Injury to the skin; lichen planus often appears where the skin has been scratched—isomorphic response
• Localised skin disease such as herpes zoster
• Systemic viral infection, such as hepatitis C
• Contact allergy, such as to metal fillings in oral lichen planus (rare)
• Drugs, antibiotics, Arsenic,iodide compounds,diuretics, certain kinds of dye, gold, quinine, quinidine and others can cause a lichenoid rash.

Causes

Lichen planus occurs when your immune system mistakenly attacks cells of the skin or mucous membranes. No one knows the exact cause of this abnormal immune response. The condition isn't contagious.

Who's affected by lichen planus

Lichen planus is thought to affect 1-2% of the worldwide population. It's more common in adults over the age of 40. Lichen planus of the skin affects men and women equally. However, oral lichen planus is more common in women. The mouth is affected in around 50% of all cases of lichen planus (oral lichen planus).

Symptoms of lichen planus

Some of the most common symptoms of lichen planus include the following:

• purplish-colored lesions or bumps with flat tops on your skin or genitals
• lesions that develop and spread over the body during weeks or a few months
• itching at the site of the rash
• lacy white lesions in the mouth, which may be painful or cause a burning sensation
• blisters, which burst and become scabby thin white lines over the rash

The most common type of lichen planus affects the skin. Over the course of several weeks lesions appear and spread.Less commonly the lesions can occur in areas besides the skin or genitals. These may include:

• mucous membranes
• nails
• the scalp

Diagnosis of lichen planus

Anytime you see or feel a rash on your skin or lesions in your mouth or on your genitals, you should see your doctor as soon as possible.

Oral lichen planus is often diagnosed by a dentist during routine dental check-ups.

Your primary care doctor or dermatologist may be able to tell that you have lichen planus simply by looking at your rash. To confirm the diagnosis, you may need further tests. Tests could include a biopsy, which means taking a small sample of your skin cells to view under a microscope, or an allergy test to find out if you are having an allergic reaction. If your doctor suspects the underlying cause is an infection, you may need to have a test for hepatitis C.

Treating lichen planus

For mild cases of lichen planus, which usually clear up in weeks or months, you may not need any treatment. If the symptoms are uncomfortable or severe, your doctor can prescribe medication.  Medications often prescribed include:

• corticosteroids reduce inflammation and can be topical, oral, or given as an injection
• antihistamines reduce inflammation and may be particularly helpful if your rash is triggered by an allergen
• nonsteroidal creams are applied topically and can suppress your immune system and help clear up the rash
• light therapy treats lichen planus with ultraviolet light

General Management

There are other things you can try at home to complement your prescription treatments. These include:

• avoiding scratching
• applying cool compresses to the rash
• using OTC anti-itch creams

It can be difficult to prevent oral lichen planus, but to keep the lining of your mouth healthy it's recommended that you:

• stop smoking (if you smoke)
• avoid drinking large amounts of alcohol
• have a healthy, balanced diet, including plenty of fresh fruit and vegetables
• maintain good oral hygiene by cleaning teeth at least twice a day, and having regular dental check-ups, so that any problems with your teeth or mouth can be identified and treated early.

Lichen planus of the genitals

• avoid washing with soap or bubble bath – use plain warm water or a soap substitute instead, such as aqueous cream
• use an emollient, such as petroleum jelly, before and after urinating
• applying ice packs to the affected areas may soothe itching and swelling (never apply an ice pack directly to your skin – wrap it in a clean tea towel before placing it on your body)
• women should avoid wearing tights
• Talk to your doctor before adding OTC products to your treatment plan. This way you’ll be certain that nothing you might take will interact with prescription medications you’re taking.

Sources :

1. http://emedicine.medscape.com/article/1123213-overview
2. https://www.dermnetnz.org/topics/lichen-planus/