Lichen Planus

General Information
Lichen Planus (LP) is a common skin condition that causes pruritic reddish-purple, shiny flat-topped bumps. The sizes of the papules may vary from small pin point to larger then a centimeter. White lines may develop on the bumps called Wickham’s striae. LP may affect any area of the body, but is frequently noted on the inner part of the wrists, the ankles and the lower back. It can also occur on the neck, legs, and genitals and occasionally on the scalp or nails. Lichen planus is not a contagious condition. The cause is unknown but has been linked to an allergic reaction or an immune reaction provoked by a viral infection. Inflammatory cells attack skin cells mistaking them as foreign. Treatment of the condition is to relieve the itching and to improve the appearance of the rash, which normally takes around a year to heal on their own. The most common treatment used include topical steroids or systemic steroids.

Epidemiology
Affects 1% – 2% of the general population

Etiology
Unknown; May be related to an allergic or immune reaction

Pathogenesis
Inflammatory cells attack skin cells mistaking them as foreign

Clinical
Reddish-purple, shiny flat-topped bumps that may be discrete or arranged in groups of lines or circles. Some may have the appearance of white lines called Wickham’s Striae.

Histology
Irregular acanthosis and colloid bodies in the epidermis with liquefactive degeneration and linear fibrin deposition in the basal layer. The upper dermis has a bandlike infiltrate of lymphocytes and histiocytes.

Bibliography
1. “Lichen Planus” (Online). March 2008. http://www.emedicine.com/DERM/topic233.htm (visited: March 22, 2008) 2. “Lichen Planus” (Online). December 2007. http://www.dermnetnz.org/scaly/lichen-planus.html (visited: March 21, 2008)

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 Lichen Planus