The development of effective SARS-CoV-2 mRNA vaccines has been a significant accomplishment. Adverse events are extremely rare, but continued surveillance is important, especially in at-risk populations. In 5-patients with preexisting immune dysregulation, hyperinflammatory syndromes, including hemophagocytic lymphohistiocytosis, developed after SARS-CoV-2 mRNA vaccination. Early recognition of this rare condition is essential.

A 56-year-old African American man with a history of well-controlled HIV presented to the rheumatology clinic with longstanding bilateral foot pain. History of present illnessThe patient's bilateral foot pain began 10 years previously and had progressed since, with difficulty in ambulation. He denied any history of trauma, nor was there musculoskeletal pain elsewhere. He noticed gradual, chronic swelling of both feet that was more prominent on the left, with decreased range of motion in his ankles, further limiting ambulation. During this period there was gradual, progressive skin thickening and hyperpigmentation of the bilateral lower extremities, most noticeable over the last 4 years. He denied any paresthesia.