SARS-Cov2 infection and DH:
Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) patients
have also begun to display DH. It is difficult to determine whether DH
occurs more frequently following SARS-CoV-2 infections by looking at
case reports/series alone. The latter, however, suggests that the
clinical presentation of DH in SARS‑CoV‑2 patients is more
extensive/severe [22, 40, 41]. Strikingly, according to the
observations of others [42, 43] and ourselves, most of these DHRs
were observed during the first wave of infections in 2020, and mostly in
patients with a severe disease course. These DHs were characterized by
an extensive cutaneous involvement, prominent eosinophilia, a slow
clinical resolution, and, in DRESS patients, a lack of responsiveness to
high-dose systemic corticosteroids.
Although it is tempting to hypothesize that SARS-CoV-2 itself could act
as a warning signal and impact DH, our experimental findings suggest an
indirect rather than direct effect in promoting DH via triggering
cytokine storm. This, in turn, leads to the hyperactivation and enhanced
expression of co-stimulatory molecules on APCs/monocytes [44] and
primes a p-i T cell response to drugs. This is in line with the clinical
observations that 1) these DHR seem to occur at the later stages of
SARS-CoV-2 infections when the virus is barely still detected in the
blood, and 2) that only patients with severe SARS-CoV-2 infections are
affected.