A patient infected with SARS-Cov-2 presents with DIHS syndrome induced by olanzapine: diagnostic difficulties

Abstract Drug-induced hypersensitivity syndrome (DIHS) is a potentially life-threatening reaction. The pathology of DIHS has been connected with adverse reactions to drugs; however, it has been observed that viruses and other infectious factors may induce similar responses in the body. COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has recently become a major challenge for worldwide healthcare. The dermatological symptoms occur in approximately 5.95% of COVID-19 patients, however, they are not exclusively a manifestation of SARS-CoV-2 infection. Certain skin-related symptoms might result from therapeutic drug administration, personal protective equipment, or sanitizers used by medical personnel. The complex pathomechanism of those symptoms leads to multiple diagnostic difficulties. This article describes a case of a 40-year-old man who was admitted to the intensive care unit (ICU) due to heavy respiratory failure in the course of SARS-CoV-2 infection. The patient has been treated with olanzapine for anxiety disorder for approximately 4 years. On the seventh day of treatment, the patient presented with a maculopapular rash, fever, and swollen upper lip. Because of these presented symptoms, the patient has been diagnosed with drug-induced hypersensitivity syndrome (DIHS). The results of blood analysis showed elevated levels of acute phase markers, liver and kidney damage markers, which are present both during COVID-19 and DIHS. Furthermore, the patient presented with peripheral eosinophilia, which is a distinctive feature of DIHS. In the course of COVID-19, the laboratory-measured levels of eosinophilic granulocytes declined to 0. Therefore, in the active phase of SARS-CoV-2 infection, the eosinophilia connected with DIHS was difficult to assess. In this paper, we compare and contrast the clinical and laboratory symptoms of COVID-19 and DIHS syndrome, describe patient's case and explain the diagnostics difficulties resulting from the concomitance of those disease entities.