Disseminated bartonellosis and EBV reactivation in an adolescent treated with upadacitinib.

BACKGROUND: Bartonella henselae is responsible for disseminated infections in immunocompromised patients. Upadacitinib is a JAK inhibitor used since 2021 for the treatment of severe atopic dermatitis in adolescents over 12-years. We report here the case of disseminated Bartonellosis in a 15-year-old male treated with upadacitinib.

CASE PRESENTATION: This patient presented with fever and abdominal pain. Laboratory tests showed inflammation, rhabdomyolysis and acute renal failure. Imaging studies revealed lymphadenopathies, hepatosplenic, renal and pulmonary nodules, pleural and peritoneal effusions and spleen abscesses. Bartonella henselae serology was positive for IgG and IgM. Treatment with doxycycline resolved the symptoms. We detected a concomitant EBV reactivation.

CONCLUSIONS: Bartonella henselae infection should be suspected in immunocompromised patients presenting with fever of unknown origin. Upadacitinib is responsible for rapid immunodepression, which can lead to viral reactivation and severe bacterial infections. Randomized controlled trials are needed to establish a consensus on treatments for the various forms of Bartonellosis.