Lichen Planus

The Inflammatory Itchy Skin Rash

Jun 23, 2009 Hanish Babu

Lichen planus is an inflammatory skin disease, of acute or chronic duration, characterized by itchy, flat, violaceous skin rash affecting the skin and mucous membranes.

Five P’s designate the characteristics of lichen planus: plane, papule, purple, polygonal and pruritic (itchy). The age of onset of lichen planus is usually between 20 to 60 years, though it can occur in children and adolescents also.

Causes of Lichen Planus

It is difficult to pinpoint the exact cause of lichen planus. It is thought to be a cell mediated immune response to some allergen. The following are the common causes of lichen planus:

Drug and Metals. Gold salts, beta blockers, antimalarials, thiazide diuretics, spironolactone, penicillamine, ACE inhibitors, Calcium channel blockers, sulphonyl urea antidiabetics, non steroidal anti-inflammatory cells, ketoconazole, tetracyclines, heavy metals etc (list not complete).
Food induced. Certain food items like fish (esp. mackerel) can cause lichen planus eruptions.
Infections. Lichen planus is common in individuals with hepatitis C infection.
In addition, lichen planus like lesions occur in certain hypersensitive reactions of the body, as in graft versus host disease.
Stress induced. Stress is thought to induce, sustain and exacerbate lichen planus.
Idiopathic. Where no cause could be found.

Clinical Features of Lichen Planus

The intensely itchy purple skin rashes appear all over the body in a matter of days or gradually over a few weeks. In some individuals, the itching is moderate or non-existent, while in majority of cases the pruritus is intense and unbearable.

The rashes are shiny, flat topped raised bumps, 1 to 10 mm in size, violaceous, polygonal or oval. When examined with a hand held lens, white lines known as Wickham’s striae become evident on the surface of the bumps. Common sites involved are flexor (bending) aspect of wrists, low back, shins, scalp, head of penis and mouth. In generalized lichen planus, the whole trunk is involved. As in psoriasis, Koebner phenomenon is present in lichen planus.

In around 40-60% of individuals, oral cavity is also involved in Lichen Planus. The oral lichen planus may present as painful erosions or shallow ulcers or lace like white raised bumps inside the cheeks. The erosions may also be present on the gingiva and tongue. Annular, violaceous papules or, rarely, ulcers may be present on glans, labia majora, minora, vaginal mucosa and scrotum in both sexes.

On the scalp, lichen planus can cause thinning and scarring of the skin leading to permanent scarring type of hair loss. This is known as lichen planopilaris.

Lichen planus also affects the nails with destruction of nail fold and nail bed with a longitudinal splintering of the nail. This may cause a wing like appearance to the nails affected, known as pterygium unguous.

Different Types of Lichen Planus

Hypertrophic
Follicular
Vesicular
Actinic
Ulcerative

Natural Course of Lichen Planus

Left untreated, lichen planus can persist for months to years. Hypertrophic lichen planus can remain for decades.

How to Treat Lichen Planus.

Treatment of lichen planus involves topical therapy, intralesional injections, systemic medications and phototherapy.

Topical Treatment of Lichen Planus. Topical steroids of moderate to super potent strength help in lichen planus depending upon the thickness of the bumps. In thick hyperkeratotic lesions, the topical therapy is initiated once the thickness is reduced through intralesional injections. Salicylic acid-steroid combinations help in thick bumps of lichen planus. In erosive lichen planus of the oral cavity, cyclosporine and tacrolimus solutions as retention mouth washes are particularly effective in relieving the pain and hastening the healing the ulcers.
Intralesional Injections. Steroid injections into the thick bumps in hypertrophic lichen planus and erosive lichen planus in the oral cavity promote the healing of the lesions.
Systemic Therapy of Lichen Planus: In severe generalized lichen planus, oral medications are used. Oral prednisolone, 1-2 mg per kg per day and tapered gradually by 5 grams over a few days relieves the itching and promotes healing of the lichen planus lesions. In treatment resistant and generalized lichen planus, cyclosporine 5mg/kg/day successfully clears most itchy skin rashes of lichen planus. Oral retinoids are also effective in treatment resistant cases. Acitretin, 1 mg/kg/day along with topical steroids gives good results.
Phototherapy in Lichen Planus. Psoralens with UVA therapy and narrow band UVB therapy is effective in lichen planus which has failed to respond to other modalities of treatment.

Lichen planus, though a chronic disease, thus has many effective treatment options. Other treatments which have been found to be effective in lichen planus include mycophenolate mofetil, heparin analogues like enoxaparin and azathioprine.

Reference

Fitzpatrick's Color Atlas & Synopsis of Clinical Dermatology, Fifth Ed, 2005

Disclaimer

The information given in this article is for educational purpose only so that patients are aware of the options available. No diagnosis should be made or treatment undertaken without first consulting your doctor. If you do so, the author or suite101 will not be responsible for any consequences. The images provided are for illustration purpose only.

The copyright of the article Lichen Planus in General Medicine is owned by Hanish Babu. Permission to republish Lichen Planus in print or online must be granted by the author in writing.