A case report of necrotizing fasciitis caused by Haemophilus influenzae co-infection in the setting of COVID-19 pneumonia.

Introduction And Importance: Necrotizing fasciitis is an aggressive skin and soft tissue infection that is a surgical emergency, and Haemophilus influenzae (H. flu) is a rare cause. We present a case of H. flu co-infection causing necrotizing fasciitis in the setting of COVID-19 pneumonia.

Case Presentation: A 56-year-old male presented with 2 weeks of upper respiratory symptoms. He was unvaccinated against COVID-19 and tested positive for COVID-19 five days prior. He developed respiratory failure requiring intubation, and was treated with dexamethasone, remdesivir, and tocilizumab for COVID-19 pneumonia. On hospital day 2, he was hypotensive with new rapidly evolving erythematous lesions with crepitus of his lower extremities suspicious for necrotizing fasciitis. He underwent wide excision and debridement with significant hemodynamic improvements. H. flu co-infection was identified from blood cultures. Aberrant cells with 94 % lymphocytes were noted and suggested chronic lymphocytic leukemia (CLL) that was not previously known. He developed progressive lesions globally, concerning for purpura fulminans with clinical disseminated intravascular coagulation and neurological decline ultimately leading to withdrawal of care.

Clinical Discussion: COVID-19 infection is often associated with concomitant opportunistic infections. Our patient was also immunocompromised by CLL, diabetes, chronic steroids, and initial appropriate COVID-19 treatments. Despite appropriate treatments, he could not overcome his medical comorbidities and multiple infections.

Conclusion: Necrotizing fasciitis caused by H. flu is rare, and we present the first case as a co-infection in the setting of COVID-19 pneumonia. Due to the patient's immunocompromised state with underlying CLL, this proved to be fatal.