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.

Erythema exudativum multiforme-like exanthema in a patient with Q fever: a case report and literature review.

Q fever is a rare worldwide zoonosis, caused by the rickettsial bacteria Coxiella burnetii. There are many clinical manifestations of infection, but the most common ones are fever, atypical pneumonia, and/or liver disease. Cutaneous involvement, however, is not a typical feature of Q fever, but it is nevertheless present in up to 20% of cases. We present a 42-year-old male patient with Q fever and erythema exudativum multiforme (EEM)-like parainfectious exanthema, which to the best of our knowledge has not been described before. We recommend considering Coxiella burnetii infection in the differential diagnosis of an EEM-like rash in a patient with an unexplained or "query" fever.

Cutaneous leukocytoclastic vasculitis following COVID-19 vaccination with Ad26.COV2.S vaccine: a case report and literature review.

Cutaneous vasculitis is a recognized and potentially serious adverse event of immunization with several vaccines, and COVID-19 vaccines are no exception. We present a case of cutaneous leukocytoclastic vasculitis occurring 17 days after inoculation with adenoviral vector vaccine (Ad26.COV2.S) in a previously healthy 30-year-old patient with no history of prior adverse events following vaccination. Transient laboratory abnormalities (mild proteinuria, cryoglobulinemia, and slightly diminished C3 complement level) were also noted, but they resolved with the resolution of skin changes after treatment with topical steroids. Although the frequency of cutaneous vasculitis after COVID-19 vaccines is extremely low, it presents an important challenge for the clinician when faced with an uncertain and delicate decision whether these patients can safely receive booster doses of COVID-19 vaccine. Because vaccination certificates are necessary for day-to-day activities and have a limited validity date, this may be an uncomfortable issue.