Viral Polyarthritis

Symmetrical polyarthritis is a well-recognised manifestation of infection with:

• Alphaviruses: Ross River virus, Barmah Forest virus, chikungunya virus
• Flaviviruses: dengue virus, Zika virus, yellow fever virus
• Parvovirus B19
• Rubella virus (and its live-attenuated vaccine)
• Hepatitis B and C viruses
• HIV

Herpesviruses (EBV, CMV, VZV), adenovirus and enterovirus can also cause arthritis, but less frequently — these have a lower predilection for joints.

Diagnosis

• Usually clinical — investigations are not routinely required.
• Typically accompanied by influenza-like symptoms (myalgia, fever, headache, red eyes) and a maculopapular rash.
• Symptoms usually peak at 1–2 weeks and largely resolve by 6 weeks, though arthritis/myalgia occasionally persist for months (notably with chikungunya and Ross River virus, which can cause persistent arthralgia in a meaningful minority of patients for months to years).
• Test for hepatitis B/C and HIV where indicated.
• If viral serology is performed, confirming a recent infection requires an appropriate rise between paired acute and convalescent samples — acute sample ideally within 1 week of onset, convalescent sample at 14–21 days.

Management

• Self-limiting — no specific antiviral treatment.
• Reassurance, NSAIDs, paracetamol.
• If symptoms are not improving by 6 weeks, or significant symptoms persist beyond 12 weeks regardless of improvement, reconsider rheumatoid arthritis or another primary inflammatory arthritis — see rheumatoid-arthritis.md.