Fig. 12.

The patient was a 66-year-old man who developed a urticarial vasculitic process on the right arm and right flank 9 days after receiving the first Moderna COVID-19 vaccine on February 22, 2021 (case 4). (A) Numerous erythematous papules are visible on the arms, thighs, and back (reproduced with permission from Dr. Jalong Gaan, New York, NY). The biopsy demonstrated 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. (A) Leukocytoclasia and red cell extravasation are present, although with no evidence of mural and or luminal fibrin deposition. (C) A few microvessels in the deep dermis were interleukin 6 positive. COVID-19, coronavirus disease 2019.