Bullous Erythema Multiforme Associated with Parvovirus B19 DNA Detected in Blister Fluid in an Immunocompetent Adult: A Case Report

Abstract

Background: Bullous erythema multiforme (EM) major is an uncommon mucocutaneous disorder, and its association with Parvovirus B19 is exceptionally rare. This report describes an immunocompetent adult with Parvovirus B19 DNA detected locally in blister fluid after common infectious triggers were excluded. Case Presentation: A previously healthy 29-year-old man developed a high-grade febrile illness followed by a rapidly progressive, painful, generalised vesiculobullous eruption involving the skin and oral, ocular, and genital mucosae. Within one week, the lesions evolved into characteristic target lesions. Histopathological examination demonstrated an atrophic epidermis, scattered apoptotic keratinocytes, interface dermatitis, and a predominantly neutrophilic perivascular infiltrate, supporting bullous EM major. Investigations for herpes simplex virus, varicella-zoster virus, Mycoplasma pneumoniae, SARS-CoV-2, hepatitis B and C viruses, HIV, cytomegalovirus, and Epstein-Barr virus did not identify an active trigger. Parvovirus B19 serology indicated previous exposure, and blood polymerase chain reaction was negative; however, Parvovirus B19 DNA was detected in fluid aspirated from an intact blister. The patient received supportive care and oral amoxicillin-clavulanate for suspected secondary bacterial superinfection, with complete cutaneous and mucosal resolution within one month and no recurrence during follow-up. Conclusion: The findings support an association between bullous EM major and localised Parvovirus B19 DNA detection, although causality cannot be established. Lesional molecular testing may assist diagnostic evaluation in carefully selected atypical cases.