Wednesday, November 12, 2014

Lichen Planus

A 45-year-old woman presents to clinic with a new pruritic rash on the flexor surface of her left forearm. Her medical history is significant for Wilson disease, and she was recently started on penicillamine, a copper-chelator. 

On exam she has Kayser-Fleischer rings in both eyes and purple, polyangular papules on her left forearm. On closer inspection, fine white streaks cover the surface of the papules.

A clinical diagnosis of lichen planus is made. Penicillamine is discontinued. What is the best treatment option at this time?

A. Oral steroids
B. Oral antihistamine
C. Topical steroids
D. Azathioprine
E. B and C only

The answer is E: B and C only. This patient has lichen planus (LP) as a cutaneous inflammatory reaction to penicillamine. Clinical identifiers for LP include the Four Ps (purple, polygonal, pruritic, papules), as well as Wickham striae, the fine white lines covering the papules. Other drug exposures that have been linked with LP include gold, chloroquine, and methyldopa.
This is a local rash, so the best initial treatment would be topical steroid and oral antihistamine for relief from itching (E). Oral steroids and more potent immune modulators (azathioprine, cyclosporine) should be used with more generalized, systemic LP.

Lichen Planus

Lichen planus is a common, distinct inflammatory disorder that affects the skin, mucous membranes, nails, and hair. 
Lesions appear as symmetric, grouped, erythematous to violaceous, flat-topped, polygonal papules. Close inspection of the lesions with a hand lens and after application of mineral oil will reveal fine white lines (Wickham striae). Etiology of the dermatosis is diverse and includes drugs, metals, and infections (especially hepatitis C), which result in alterations of cell-mediated immunity. Women are affected more often than men, and the typical age of onset is between 30 and 60. Trauma may
cause the Koebner phenomenon and linear arrangements.

Treatment is with topical and systemic corticosteroids or cyclosporine.■ Four Ps: purple, polygonal, pruritic, papules
■ Cutaneous lesions: distributed typically on flexural aspects of arms and legs but may become generalized; symptom is pruritis
■ Oral lesions: milky-white reticulated papules, which may become erosive or ulcerate; symptom is pain


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