Dermoscopy in diagnosis of inflammatory dermatoses: a case report of patient with lichen planus

Introduction: Dermoscopy, traditionally used in diagnosing pigmented lesions and skin cancers, has developed as a helpful method in assessing inflammatory dermatoses. By providing improved visualization of vascular patterns, scales, and follicular structures, dermoscopy helps in distinguishing between various inflammatory skin disorders. Lichen planus (LP) is an inflammatory dermatosis that involves the skin, scalp, nails and mucous membranes. Characterized by pruritic, violaceous, flat-topped papules, LP has a distinct clinical presentation, but dermoscopy provides enhanced diagnostic accuracy by revealing specific patterns not visible to the naked eye. White crossing streaks (Wickham striae) are the main characteristic of lichen planus. Vessels with different appearance (dotted and linear) may be found at the periphery of the lesion. This report outlines the role of dermoscopy in diagnosing LP, highlighting key dermoscopic patterns.
Case report: A 41-year-old female patient without disease history, no drug intake nor buccal involvement came in the hospital due to pruritic erythematous papules with two months of evolution localized on the trunk and around the wrists on both of his arms. Dermoscopy of the lesion on the patient’s trunk revealed small pinpoint vessels associated with white crossing streaks on an erythematosus background. Histopathologic examination revealed characteristic interface dermatitis. The diagnosis of lichen planus (LP) was considered after clinical and dermoscopic correlation, and confirmed histologically. Screening for hepatitis B and C was negative. Under appropriate treatment the lesions regressed.
Conclusion: Dermoscopy plays an important role in the diagnosis of lichen planus. The dermoscopic patterns can help differentiate LP from other dermatoses, especially in early or atypical cases. Dermoscopic signs of active LP include Wickham striae (WS) and vascular structures (red dots, radial capillaries). WS are considered pathognomonic of LP. However, their absence should not exclude the diagnosis. WS could be absent in treated LP. Dermoscopy provides better treatment outcome in patients with LP, as vascular structures and WS tend to disappear under appropriate treatment.