An otherwise healthy man presented with three days of pain and swelling in his right submandibular and cheek areas. In the previous 24 hours, he had also developed left testicular pain that was worse with walking and improved with sitting. He had nausea and a painless canker sore on his lip but remained afebrile and was not fatigued. The patient's 22-month-old son was diagnosed with coxsackievirus infection five days before the patient's visit. The patient received immunity screening for measles, mumps, and rubella for work two weeks before onset of symptoms, and he had immunoglobulin G (IgG) antibodies to all three viruses. His immunizations were up to date.

Physical examination revealed swelling and tenderness on the right side of his neck and submandibular area without erythema or rash (Figure 1 and Figure 2). He also had bilateral testicular swelling and tenderness.

Initial point-of-care testing included negative rapid streptococcal screening results and normal urinalysis findings. Throat culture and complete blood count findings were negative. Testicular ultrasonography showed orchitis and epididymitis. Serology was negative for mumps IgM and coxsackievirus IgM, and positive for mumps IgG and coxsackievirus IgG.