Lichen Planus

What causes Lichen Planus?

A precise cause of lichen planus is not well understood but it is thought to involve an abnormal immune response. The body’s immune system starts to attack cells in the skin and mucous membranes. We also know that several factors may trigger it, for example

• Viruses such as hepatitis C, hepatitis B, human herpes virus and varicella zoster virus.
• Substances in contact with the skin such as mercury, copper, and gold, such as in tooth fillings (tooth amalgam).
• Medicines such as some tablets for high blood pressure, medicines to treat malaria, infections, and depression.
• Stress and anxiety.
  
  

Is Lichen Planus hereditary?

No, it is not hereditary. However, the tendency to get lichen planus can sometimes run in families, especially twins, though this is not an absolute.   

What does Lichen Planus of the skin feel and look like?

Lichen planus on the skin is usually, but not always, itchy. Other symptoms depend on which parts of the body it affects. These symptoms may be pain (for example, if the mouth, vulva or vagina is affected), affecting appearance (hair loss in scalp lichen planus or dark coloured patches on the face if the face is affected), or function (for example, if the nails are affected). 

The typical skin rash of lichen planus is made up of clusters of shiny, slightly raised pink or purple-red spots, usually measuring 1-3 mm in diameter. A close look may show fine white streaks on their surface. The rash usually affects the insides of the wrists, around the ankles and on the lower back, but can spread more widely. Lichen planus can also appear in a line where the skin has been scratched or injured (this is called Koebner’s response). The rash can heal to leave marks which are darker than the original skin colour.  

In skin of colour, lichen planus of the skin may not show the typical pink or purple colour; the rash may be darker than skin colour, may have a purplish hue, but will show the characteristic fine streaks. The streaks may be white, or lighter than the background skin colour.   

What are the other types of Lichen Planus and what do they look like?

Other types of lichen planus include: 

• Thickened ('hypertrophic') lichen planus, which tends to affect the shins and can look like warts.
• Ring-shaped ('annular') lichen planus, which tends to affect the armpits, penis, scrotum, and groin.
• Lichen planus of the scalp (lichen planopilaris) can cause patches of hair loss in areas. Hair loss is usually permanent.
• Lichen planus can sometimes develop on sun-exposed areas, such as on the face,(‘actinic’ lichen planus).
• Nails can be affected, with thinning of the nail plate, or the nails becoming rough and grooved. Affected nails can sometimes become permanently scarred.
• Lichen planus often affects the inside of the cheeks and the gums, and this can be seen in about 50% of people who have it on the skin (see Patient Information Leaflet on oral lichen planus).
• Errosive Lichen planus is a painful type of lichen planus affecting the genital area. Rarely, when affecting the vulva and vagina, it can be associated with a severe form of lichen planus that also affects the gums and oesophagus (vulvo-vaginal-gingival syndrome).
  In some patients, oval grey-brown flat marks appear on the face and neck or trunk and limbs without a preceding rash. This is called lichen planus pigmentosus. This type of lichen planus is more common in people with darker skin tone.
• Lichen planus can sometimes blister (‘bullous’ lichen planus). This is rare and usually affects the lower legs.

There is a low risk of skin cancer (squamous cell carcinoma) developing in areas of persisting, severe lichen planus, such as in hypertrophic lichen planus or affecting mucous surfaces (erosive lichen planus) such as in the mouth and gums, vulva and vagina, and penis.

How is lichen planus diagnosed?

The diagnosis of lichen planus is usually made by a doctor examining the rash. Sometimes, it may be difficult to tell between lichen planus and other skin conditions such as eczema, warts, or a rashes caused by medications. If the diagnosis is not clear, a skin biopsy, performed under local anaesthetic, made be needed to confirm the diagnosis. Your doctor will advise you if this is required. 

How is lichen planus treated?

Appropriate treatments for this condition depend upon the type of lichen planus present, the severity of symptoms, and if there any specific risks, such as hair loss or nail damage. 

Mild lichen planus without symptoms doesn't always need to be treated. Moderated lichen planus of the skin are usually treated with steroid creams or ointments (topical steroids). Potent and/or very potent steroids are usually needed. These should usually be applied carefully once a day, as instructed by your doctor, to affected areas.

Severe or widespread lichen planus. For severe or widespread lichen planus, the initial treatment is with a course of steroid tablets oral steroids), in combination with topical steroids. If there is little improvement in the rash, further treatments such as ultraviolet therapy (narrow band ultraviolet B therapy, or NB-UVB) or acitretin (a tablet treatment) may be considered. Further treatments include methotrexate and hydroxychloroquine for stubborn disease.  

NHS Fife kindly reproduces this information based on accurate information about the subject compiled from a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor.