Exanthematous lichen planus in a child and Mycoplasma pneumoniae: a case report and literature review

Lichen planus (LP) is a chronic inflammatory disease of the skin and mucous membranes. The disease usually affects adults and is only rarely encountered in children. Typically, skin lesions include violaceous, polygonal, flat papules and plaques, affecting predilection sites such as the wrists, ankles, and lower back. However, clinical presentation can be heterogeneous and is often atypical in children. Various precipitating factors are known to play an important role in the pathogenesis of lichen planus, some of which may also be coincidental. LP occurring after an infection with Mycoplasma pneumoniae is a rare occurrence. We present the case of a 13-year-old boy with pruritic papular skin lesions on the extremities and trunk. In view of the clinical and histopathological findings, LP exanthematicus was diagnosed. To the best of our knowledge, our case is the first of pediatric exanthematous LP after M. pneumoniae infection that has been reported so far.