Lichen planus

Lichen planus is a condition affecting the skin and mucous membranes. The mucous membranes are the moist, pink tissues that line the inside of the mouth, vagina, and other organs. It usually affects adults and is not contagious. Although the condition can go away on its own after several months or years, recurrences are not uncommon.

Typical signs and symptoms of lichen planus include the following:

• Red or purple papules (i.e., bumps on the skin) with a white centre
• Severe itching
• Rough skin on the affected area
• Hair loss on the affected area
• Whitish lesions or painful sores on the mucous membranes

The lesions are usually symmetrically distributed, which means the right and left sides of the body are often affected equally. Lichen planus can appear anywhere on the body, but mainly affects the following areas:

• Wrists
• Ankles
• Mouth
• Genitals

In some people, lichen planus affects the nails as well. When this happens, the nail plate becomes thinner and develops white longitudinal ridges. It can lead to the complete and permanent destruction of the nails.

After the lesions have healed, the affected skin may remain darker than it was before the lichen planus flare up. This is called permanent hyperpigmentation. In addition, some injuries may never go away, especially when they occur in the mouth. The presence of mouth lesions slightly increases a person's risk of developing oral cancer, but this risk is not directly associated with lichen planus.

The skin lesions usually aren't very painful. Lichen planus often affects the mouth as well as the skin. Although the mouth lesions usually don't hurt, they can progress and extend deeper into the tissue, at which point they become painful. As a result, nutrition can be affected. Genital lesions are often painful.

Causes and triggers

The exact cause of lichen planus is unknown. However, experts think it might be due to an inadequate immune system response caused by certain external factors. Stress can often trigger a reaction. Other factors include exposure to the following:

• Certain medications (e.g., beta-blockers, non-steroidal anti-inflammatory drugs, some diuretics)
• Certain infections (e.g., hepatitis C)
• Certain metals (e.g., gold salts, mercury)

Inadequate oral or skin hygiene can make lichen planus symptoms worse and cause complications, such as infections. In order to reduce the risk of developing mouth cancer, it's best to quit smoking and stop drinking alcohol. All medications that trigger the condition should also be avoided.

Treatment

Most of the time, lichen planus heals on its own after a few years, except when it occurs in the mouth. Medications are often applied to the lesions (e.g., creams, ointments) to relieve itching and pain. Oral treatments may also be necessary. Treatments will depend on the affected area and the severity of symptoms.

Some people may also benefit from ultraviolet light therapy to alleviate their condition.

Certain habits can make lichen planus symptoms worse. Here are a few tips to help manage symptoms:

• Do not scratch the lesions
• Wash and gently wipe the affected skin in the shower
• Practise good hygiene around the affected areas of the skin and mucous membranes

When should I see a health care professional?

Speak with your health care provider if you experience any of the following symptoms:

• Unusual lesions on your skin, in your mouth, or around your genitals
• Signs of infection such as redness, heat, swelling, fever, or pus