9
Lichen Planus and Lichenoid Dermatoses
Lichen Planus
• Flat-topped (lichenoid) papules that are often polygonal in shape and purple in color may coalesce into plaques (Fig. 9.1); lesions usually resolve with hyperpigmentation (Fig. 9.2).
Fig. 9.1 Lichen planus. Violaceous papules and plaques with white scale and Wickham’s striae. Courtesy, Tetsuo Shiohara, MD.
Fig. 9.2 Lichen planus of the dorsal hand. Note the flat-topped nature of the lesions and the post-inflammatory hyperpigmentation. Courtesy, Frank Samarin, MD.
• A characteristic finding is Wickham’s striae, a network of fine white lines on the surface of papules and plaques (Fig. 9.3).
Fig. 9.3 Wickham’s striae in lichen planus. This patient has a hypertrophic lesion in addition to classic lesions. Courtesy, Julie V. Schaffer, MD.
• There are multiple variants of lichen planus, from exanthematous to hypertrophic (Table 9.1; Figs. 9.4 and 9.5).
Table 9.1
Variants of lichen planus.
* If erosive variant plus lichenoid cutaneous lesions, DDx includes paraneoplastic pemphigus.
AutoAb, autoantibody; BP, bullous pemphigoid; BPAG2, bullous pemphigoid antigen 2 (type XVII collagen); DIF, direct immunofluorescence; HCV, hepatitis C virus; IIF, indirect immunofluorescence; LE, lupus erythematosus; LSC, lichen simplex chronicus; SCC, squamous cell carcinoma.
Fig. 9.4 Variants of lichen planus. A Exanthematous variant with multiple papulosquamous lesions. B Annular variant with thin elevated rim and central hyperpigmentation. C Atrophic variant with large, long-standing lesions. D Bullous variant with vesicobullae arising in pre-existing plaque. E Hypertrophic variant with thick plaques on the shins, a common location for this variant. F Inverse variant of the axillae; note the purple color. G Pigmentosus variant with only hyperpigmented lesions in an intertriginous zone. H Linear variant along Blaschko’s lines with follicular spines. B, Courtesy, Frank Samarin, MD; C, Courtesy, Tetsuo Shiohara, MD. F, Courtesy, Jeffrey Callen, MD.
Fig. 9.5 Lichen planus of the nails and oral mucosa. A Thinning of the nail plate with lateral loss. B Violaceous discoloration of the periungual area with pterygium formation. C
