A six-year-old boy presented to the emergency department with a rash and central pustule on his trunk that appeared three days earlier. He had a fever of 102°F (39.9°C). The day before presentation, his mother noted painful annular lesions on his legs. He had completed treatment for streptococcal pharyngitis three months earlier and did not have a sore throat, runny nose, or cough. He was prescribed a 10-day course of cephalexin for cellulitis and followed up with his family physician six days later. At the follow-up, he had a fever and new lesions on his legs. Acetaminophen provided limited pain relief.

Physical examination revealed numerous poorly demarcated, annular lesions that were warm, raised, and markedly tender to palpation. The lesions were primarily on the legs (Figure 1 and Figure 2), with several on the forearms. The lesions showed no fluctuance or ulceration. The cellulitis on his trunk was clearing.

A rapid polymerase chain reaction test was negative for COVID-19. He had increased platelets (552 × 10³ per μL [552 × 10⁹ per L]), C-reactive protein (3.5 mg per dL [350 mg per L]), erythrocyte sedimentation rate (55 mm per hour), and streptolysin antibody (815 IU per mL). White blood cell count and antinuclear antibody findings were negative. The patient's fevers dissipated slowly over two weeks, and the pain resolved over one month of treatment with ibuprofen.