Fig. 16.

(A) A man aged 66 years developed this urticarial reaction process after receiving the COVID-19 Moderna vaccine. (B), (C) The biopsy specimen demonstrates an inflammatory process within the dermis, exhibiting urticarial-like features. In particular, there is a mixed infiltrate that is interstitial and perivascular composed of lymphocytes, monocytes, and neutrophils along with a few eosinophils with concomitant dermal edema. Inflammatory cells migrate through the vessel wallwithout fibrin deposition, although nevertheless there is focal leukocytoclasia and red cell extravasation, a constellation of findings consistent with urticarial vasculitis(B, hematoxylin and eosin, 200 ×; B, hematoxylin and eosin, 400 ×) COVID-19, coronavirus disease 2019.