Introduction
Delayed-type drug hypersensitivity reactions (DDH) result from T cell-mediated immune responses against drugs (Gell and Coombs type IV allergic reaction)1. DDH affect about 7% of the general population2,3. The most common DDH are maculopapular drug exanthemas (maculopapular drug rashes ; MDR), which are typically mild reactions that are limited to the skin and controllable with topical corticosteroids4. In contrast, severe cutaneous hypersensitivity reactions are rare, but life-threatening when they occur. Drug reaction with eosinophilia and systemic symptoms (DRESS) belongs to the category of severe DDH5.
Since the beginning of the Coronavirus disease 19 (COVID-19) pandemic6,
different types of DDH have been reported in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients7, raising the question as to how COVID-19 is associated with their development. We and others have reported glucocorticoid-refractory severe DRESS with massive eosinophilia in COVID-19 patients8,9. Besides DDH, other cutaneous eruptions have been associated with SARS-CoV-2 infection and have been observed in approximately 1-20 % of the patients10-15. These various skin manifestations of SARS-CoV-2 infection16,17may be due in part to the SARS-CoV-2 spike protein receptor (angiotensin-converting enzyme 2, ACE2) being expressed by keratinocytes17Supporting this possibility is the finding that SARS-CoV-2 RNA can be directly isolated from the skin of some COVID19 patients18.
Here we report a series of MDR cases in severely ill COVID-19 patients and sought to address how MDR occurring in COVID-19 patients (COVID-MDR) differs from MDR not related to COVID, and DRESS.