Lichen planus

In the USA, lichen planus (LP) has been reported to affect 1% of new patients seen at health care clinics, with most patients being between the ages of 30 and 60, although it can affect any age. There does not seem to be any gender differences. LP can be described as a cell-mediated immune response of unknown origin. The response may be provoked by a viral infection (and there may be a particular association with hepatitis C), by a drug or by a stressful event (Chuang and Stitle, 2008).

Lichen planus represents a wide range of clinical manifestations which are described below. However, the disease is characterised by a number of histological features:

• Marked liquefaction (conversion to liquid) of the basal layer;
• Expansion of the granular cell layer;
• Dense subepidermal infiltrate, predominantly of T-lymphocytes.

Clinically, patients may present with disease limited to one or two areas of skin, more uncommonly the presentation may be extensive affecting both skin and mucous membranes (Figure 13.3). It is not uncommon for mucous membranes to be affected without any symptoms on the skin. In 85% of cases, the lesions will clear from the skin in 18 months time (New Zealand Dermatological Society Incorporated, 2009) but where disease is more extensive and affecting the mucous membranes it can take considerably longer. In around 10% of patients there will also be nail changes.

Classic presentation
The lesions are shiny flat-topped papules which vary in size from being pin-prick to more than a centimetre. The shape of the lesion is often described as polygonal and they may be distributed closely together or widely spread, in linear formation or in rings. They are purplish in colour (known as violaceous) and there are often grey or white lines and dots scattered over the surface; these are known as Wickham’s striae. The most common locations for the lesions are wrists, lower back and ankles; however, they can occur anywhere on the body. For some people, scalp papules appear which may progress to atrophic cicatrical alopecia. Mucous membrane involvement is common; lesions are usually found on the bucal mucosa and tongue, although they can affect conjunctivae, the larynx, the tonsils, the bladder, the vulva, the GI tract and the anus. The presentation is white or grey streaks forming a reticular pattern against a violaceous background. They may become ulcerative; this is linked to an increased risk of malignant transformation, particularly in men.

Symptoms related to the skin lesions vary from nothing to severe pruritis. Scale may also be associated with LP and it tends to be the thicker, scalier areas which are most itchy. As already mentioned the lesions usually clear within 18 months, but during that time some lesions will disappear and other new ones appear. Hyperpigmentation can occur where the lesions have been and this seems to be more common in darker skin colours. On the mucous membranes, lesions can be accompanied with a stinging sensation; they may become painful should the lesions deteriorate and become erosive.

Nail changes in LP occur because of nail plate thinning; this results in longitudinal grooving and ridges. Other nail changes may include subungual hyperkeratosis, onycholysis and longitudinal melanonychia. Rarely the nails may disappear altogether.

Hypertrophic LP
It has already been mentioned that the lesions can become thickened; in extreme cases, this is known as hypertrophic LP and is characterised by extreme pruritis. It usually occurs on the lower limbs particularly around the ankles. These lesions are chronic in nature and can take years to clear. When they do, scarring and hyperpigmentation can remain.

Erosive LP
This type of LP affects mucosal surfaces, usually the mouth and genitals. It is painful and usually chronic in nature. It may be associated with classical cutaneous LP or it can occur alone. The main clinical features of oral erosive LP are large, painful ulcers which heal with scarring. Healing may take weeks. The lesions can occur on the sides of the tongue, insides of the cheeks, on the gums or inside the lips. It mainly affects adults, usually women and children are rarely affected.

Genital erosive LP in women can cause extensive changes to the mucosa and structure of the genitals. The labia minora and entrance to the vagina can become red and raw; more drastically the clitoral hood can disappear and the labia minora stick to each other or the labia majora. The subsequent scarring may cause the labia majora to close over the vagina. If LP affects the inside of the vagina, it may bleed easily on contact and there is a mucky discharge. Genital erosive LP is much less common in men; it causes redness and tenderness of the glans. These changes can be extremely painful particularly when passing urine or having sexual intercourse. The latter may become impossible for women who have considerable structural changes to their genitals.

Bullous LP
This is a rare condition, blisters are seen forming either within the LP papules or alone.

Actinic LP
Lesions of LP are induced by exposure to sunlight.

Treatment for LP
The mainstay of treatments for LP are topical steroids. The cutaneous form will need to be treated with potent or very potent topical products, usually for a 4- to 6-week course. The resolving lesions will flatten to be the same as the rest of the skin surface; it is important to monitor this as the sign of clearance as some pigmentation may remain. If the disease persists, intermittent courses of topical steroids will be needed. For more severe disease, particularly erosive and hypertrophic variants, oral immunosuppressive therapy may be required. This may be oral steroids, ciclosporin or methotrexate.


For those with oral and genital disease, good hygiene measures should be maintained. Soaps should be avoided when washing the genital area; a soap substitute such as aqueous cream may be used instead. A petrolatum emollient ointment may be helpful to provide some relief from general discomfort. Applying topical steroids in the oral cavity will be enhanced by an inhaler spray or pastes. A number of small studies reviewed by Ruzicka et al. indicate that topical calcineurin inhibitors, specifically topical tacrolimus, are helpful for erosive genital and oral LP (Ruzicka et al., 2003). Specifically a 2008 study considered 10 patients with erosive oral LP, 7 of whom had no lesions after 30 days of pimecrolimus compared to 2 with no lesions in the control group. A further 30 days of treatment cleared the lesions in the patients who did not respond in the first 30 days (Volz et al., 2008). This is, however, using the treatment off license.