ABSTRACT
Introduction: The risk of toxic epidermal necrosis (TEN) depends on both drug and host factors, such as autoimmune disease. We present a case of TEN in a patient with recently diagnosed macrophage activation syndrome (MAS). Case Description: A 23-year-old previously healthy woman was admitted multiple times over 4 weeks for spiking fevers, cervical lymphadenopathy, and macular rash. Her symptoms began one week after her second SARS-CoV-2 mRNA vaccine and did not respond to outpatient treatment with azithromycin and steroids for presumed upper respiratory infection. Extensive infectious evaluation was unrevealing. She had elevated liver enzymes, cytopenias, lymphadenopathy, and splenomegaly. Lymph node and bone marrow biopsies were unrevealing. Further evaluation demonstrated elevated triglycerides, ferritin, and soluble IL-2 receptor. Natural killer cell function was normal. IL-18 was markedly elevated (181,803 pg/mL) supporting the diagnosis of adult-onset Still’s disease with MAS. Dexamethasone and anakinra were initiated on day 29 of illness with prophylactic atovaquone and pantoprazole. Her symptoms and labs improved until day 57 of illness when she developed a diffuse, painful, blistering maculopapular rash consistent with TEN. Potential culprit drugs were held (pantoprazole, atovaquone, and cephalosporins) and she received a short course of IVIG and cyclosporine in addition to anakinra and steroids. She required prolonged hospitalization for wound care and rehabilitation. She has recovered well and remains on prednisone and canakinumab. Discussion: The widespread innate immune activation from MAS, possibly triggered by preceding vaccination, may have augmented her risk of developing TEN. Treatment was therefore directed towards ongoing MAS in addition to TEN. [Formula presented]