# Approach to Polyarthritis

> Approach to polyarthritis for NEET-PG Medicine: symmetry, small versus large joint pattern, additive versus migratory course and serology to narrow down causes.

- Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/approach-to-polyarthritis
- Exam / course: NEET-PG · Subject: Medicine
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Harrison's Principles of Internal Medicine; Davidson's Principles and Practice of Medicine; Kumar and Clark's Clinical Medicine
- How to cite: "Approach to Polyarthritis", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/approach-to-polyarthritis

## Direct answer

Polyarthritis means inflammation of several joints, and the approach rests on the pattern: symmetry, whether small or large joints are involved, and whether joints are added over time or migrate. Symmetric small-joint involvement points to rheumatoid arthritis, SLE or viral arthritis, while asymmetric large-joint disease suggests spondyloarthritis or post-infective arthritis. Serology such as rheumatoid factor, anti-CCP, ANA and HLA-B27 then narrows the diagnosis.

## What you must remember

- **Symmetry:** the same joints on both sides suggest rheumatoid arthritis, SLE or viral arthritis, while asymmetric involvement points to spondyloarthritis, psoriatic or reactive arthritis.
- **Small-joint pattern:** metacarpophalangeal, proximal interphalangeal and wrist joints, with distal interphalangeal joints spared, is typical of rheumatoid arthritis.
- **Distal pattern:** distal interphalangeal joints, with nail pitting and dactylitis, classically point to psoriatic arthritis.
- **Large-joint pattern:** knees, ankles and hips, often with enthesitis and back pain, typical of spondyloarthritis and post-infective arthritis.
- **Additive course:** new joints are recruited over weeks and persist, as in rheumatoid arthritis.
- **Migratory course:** joints are involved in succession, each for days, as in acute rheumatic fever, gonococcal arthritis and serum sickness.
- **Stiffness:** more than one hour of morning stiffness favours inflammatory arthritis, whereas osteoarthritis typically causes stiffness lasting minutes.
- **Serology:** rheumatoid factor and anti-CCP for rheumatoid arthritis, ANA for SLE, and HLA-B27 for spondyloarthritis, with anti-CCP the more specific marker.

## A pathway for narrowing a polyarthritis

Polyarthritis is best approached as a pattern-recognition exercise rather than a single test. The steps below move from the bedside to the laboratory in a logical order, and no single clue usually settles the diagnosis on its own.

1. **Confirm inflammation:** morning stiffness lasting over an hour, warmth, swelling and night pain point towards inflammatory disease rather than osteoarthritis.
2. **Map the distribution:** record which joints are involved and whether the pattern is symmetric, small, large or mixed.
3. **Observe the time course:** ask whether joints are added over time or come and go, because the course changes the differential list.
4. **Look for extra-articular clues:** rash, uveitis, mouth ulcers, nail changes, back pain, urethritis or diarrhoea each point towards a specific disease.
5. **Order targeted serology:** RF, anti-CCP, ANA, HLA-B27 and hepatitis or parvovirus serology, chosen according to the pattern rather than ordered in bulk.
6. **Refer early:** rheumatology review should not be delayed, because early rheumatoid arthritis responds best to treatment started early.

## Where the exam tries to catch you

Polyarthritis questions usually turn on symmetry, the distal pattern and the self-limiting viral causes.

- **Trap:** calling any symmetric arthritis rheumatoid without serology — **Correct:** SLE and viral arthritis can also be symmetric, so RF, anti-CCP and ANA help to discriminate.
- **Trap:** missing psoriatic arthritis because the skin looks clear — **Correct:** nail pitting, distal joint involvement and dactylitis favour psoriatic arthritis even without obvious plaques.
- **Trap:** labelling symmetric small-joint pain in an adult woman as osteoarthritis — **Correct:** osteoarthritis usually spares the metacarpophalangeal joints, so their involvement demands an inflammatory work-up.
- **Trap:** ignoring parvovirus B19 or chikungunya — **Correct:** both cause self-limiting symmetric polyarthritis, often with rash, and both matter in endemic Indian settings.

## Frequently asked questions

### Which serology favours rheumatoid arthritis over SLE in a patient with polyarthritis?

Anti-CCP antibody is highly specific for rheumatoid arthritis, and rheumatoid factor is also positive in many patients. A positive ANA with anti-dsDNA or anti-Smith antibodies favours SLE instead.

### Why does HLA-B27 matter in asymmetric large-joint arthritis?

HLA-B27 is associated with spondyloarthritis, which often causes asymmetric oligoarthritis of large joints with enthesitis and back pain. A positive result supports the diagnosis, but a negative result does not exclude spondyloarthritis.

### Which infections cause self-limiting symmetric polyarthritis in India?

Chikungunya is the most important viral cause of symmetric polyarthritis in India, usually with fever and rash. Parvovirus B19 and hepatitis B and C can also cause polyarthritis, and these are usually self-limiting or managed by treating the underlying infection.

### What morning stiffness duration favours inflammatory arthritis?

Morning stiffness lasting more than one hour favours inflammatory arthritis such as rheumatoid arthritis. Osteoarthritis typically causes stiffness that settles within minutes of getting up.