A 43-year-old woman with medical histories of hyperlipidemia and chronic urticaria received the first dose of the Oxford-AstraZeneca COVID-19 vaccine (AZD1222 vaccine). Two days later, pruritic skin rashes developed at the vaccine injection site of the left arm, and gradually expanded to left upper arm and left chest. On physical examination, the patient had erythematous, edematous plaques with scattered, non-follicular pustules over her left upper arm and left chest (Figure 1a-c). She had a fever on the day after vaccination. She denied any other medication exposure or contact history other than the vaccination. Laboratory test showed a white blood cell count of 11.35 × 10 3 /mm 3 with 89.4% neutrophils. Pathology from skin biopsy revealed subcorneal pustules, basal layer vacuolation, epidermal spongiosis, papillary dermal edema, and superficial perivascular mixed cell infiltration with eosinophils (Figure 1d,e). In addition, numerous intravascular neutrophils were noted (Figure 1f), which may indicate acute chemotaxis. Based on the clinical history, skin presentations,