to the editor: A 68-year-old white woman presented to her family physician's office with a four-day history of diffuse bilateral pain and swelling in her wrists, hands, and lower extremities, and a temperature of 101·F (38.3·C). The patient did not have chest pain, palpitations, shortness of breath, a history of injury, or a rash. She was started on 500 mg of naproxen twice daily and was asked to follow up when her laboratory data became available. Laboratory analysis revealed a normal complete blood count, a slightly elevated erythrocyte sedimentation rate of 26 mm per hour, a C-reactive protein level of 23.0 mg per L (219.1 nmol per L), negative rheumatoid factor, and positive antinuclear antibodies (ANA) with a titer of 1:160 in a nucleolar pattern.

The patient returned five days later with a decrease in pain and swelling. Although naproxen had helped alleviate some discomfort, she had developed diarrhea and discontinued its use. At this visit, the patient reported that she had been in close contact with her grandson, whose school recently had experienced an outbreak of parvovirus B19. Subsequent testing for parvovirus B19 antibodies 12 days after the initial presentation revealed an IgG titer of 5.6 and an IgM titer of 8.1. The reference range for both IgM and IgG titer is less than 0.9, negative titer; 0.9 to 1.1, equivocal titer; and greater than 1.1, positive titer. A positive IgG and IgM titer indicates an infection within the last 7 to 120 days. This patient's titers are consistent with her clinical presentation representing an acute infection. The patient was restarted on naproxen, and a decrease in swelling and pain was noted one week later.

Parvovirus B19 infection can have a variety of clinical presentations but is most frequently an asymptomatic infection. Erythema infectiosum, also called fifth disease, causes a classic "slapped cheek" appearance. It is a parvovirus B19 infection most commonly found in children; infected patients present with a low-grade fever, malaise, and a rash. Parvovirus B19 is also known to cause an erythrocyte aplasia, transient aplastic crisis, and in the unborn, hydrops fetalis.¹ Arthralgia and arthritis can be symptoms of parvovirus B19, most commonly as acute onset symmetric polyarticular arthritis in the hands. Joint pain and arthritis occur more frequently in infected adult women than in children and adult men. These symptoms often can remain for more than two months. Common laboratory abnormalities include a positive ANA or rheumatoid factor. Forty to 60 percent of adults have antibodies to parvovirus B19.² There is a steep increase in children older than five years with IgG antibodies, probably indicating that infection is associated with beginning school.³ Treatment of arthropathy from parvovirus B19 is primarily symptom management with nonsteroidal anti-inflammatory drugs.

The differential diagnosis for polyarticular joint pain encompasses many diverse conditions.⁴ This case of acute arthropathy resulting from parvovirus B19 infection serves as a reminder to consider exposure to parvovirus B19 when a patient presents with an acute transient arthropathy.