Lichen Planus Lichen planus (LP) is a papulosquamous disorder that may affect the skin, scalp, nails, and mucous membranes. The primary cutaneous lesions are pruritic, polygonal, flat-topped, violaceous papules. Close examination of the surface of these papules often reveals a network of gray lines (Wickham's striae). The skin lesions may occur anywhere but have a predilection for the wrists, shins, lower back, and genitalia (Fig. 53-5). Involvement of the scalp, lichen planopilaris, may lead to scarring alopecia, and nail involvement may lead to permanent deformity or loss of fingernails and toenails. LP commonly involves mucous membranes, particularly the buccal. | Chapter 053. Eczema and Dermatitis Part 9 Lichen Planus Lichen planus LP is a papulosquamous disorder that may affect the skin scalp nails and mucous membranes. The primary cutaneous lesions are pruritic polygonal flat-topped violaceous papules. Close examination of the surface of these papules often reveals a network of gray lines Wickham s striae . The skin lesions may occur anywhere but have a predilection for the wrists shins lower back and genitalia Fig. 53-5 . Involvement of the scalp lichen planopilaris may lead to scarring alopecia and nail involvement may lead to permanent deformity or loss of fingernails and toenails. LP commonly involves mucous membranes particularly the buccal mucosa where it can present a spectrum of disease from a mild white reticulate eruption of the mucosa to a severe erosive stomatitis. Erosive stomatitis may persist for years and may be linked to an increased risk of oral squamous cell carcinoma. Cutaneous eruptions clinically resembling LP have been observed after administration of numerous drugs including thiazide diuretics gold antimalarials penicillamine and phenothiazines and in patients with skin lesions of chronic graft-versus-host disease. Additionally LP may be associated with hepatitis C infection. The course of LP is variable but most patients have spontaneous remissions 6 months to 2 years after the onset of disease. Topical glucocorticoids are the mainstay of therapy. Figure 53-5 Source Fauci AS Kasper DL Braunwald E Hauser SL Longe DL Jameson JL Loscalzo J Harrison s Principles i-of Interna Medicine. 17th Edition http Copyright @ The McGraw -Hill Companies Inc. AH rights reserved. Lichen planus. An example of lichen planus showing multiple flat-topped violaceous papules and plaques. Nail dystrophy as seen in this patient s thumbnail may also be a feature. Courtesy of Robert Swerlick MD with permission Pityriasis Rosea Pityriasis rosea PR is a papulosquamous eruption of unknown etiology .
