Polyarthritis and oligoarthritis

Last updated: August 14, 2025

Summary

Polyarthritis and oligoarthritis are conditions characterized by swelling and/or pain affecting multiple joints. Causes are diverse and include infections, autoimmune and inflammatory conditions, crystal deposition, and osteoarthritis. The most common causes of polyarthritis are hand osteoarthritis and rheumatoid arthritis. Clinical evaluation involves a focused history and physical examination to assess joint involvement patterns and pain characteristics and evaluate for synovitis and extra-articular symptoms. Synovitis and/or extra-articular features often suggest an inflammatory or autoimmune cause. Diagnosis varies based on the suspected condition but may include laboratory studies (e.g., CBC, inflammatory markers) and imaging (e.g., x-rays) of affected joints. Additional studies and specialist referral may be considered based on clinical suspicion. Management varies depending on the underlying cause and may include symptomatic treatment, disease-modifying agents, and/or treatment of infection.

Chalk Talk: Arthritis & Osteoarthritis 4

Etiology

Conditions are listed under their most common presentation.

Oligoarthritis (≤ 4 joints) ^[1]^[2]^[3]

Infectious (e.g., Lyme disease, gonococcal arthritis)
Autoimmune or inflammatory
Crystal deposition (rare)
- Gout
- Calcium pyrophosphate deposition (CPPD) disease (e.g., pseudogout)
Other: secondary osteoarthritis (posttraumatic arthritis)

Polyarthritis (≥ 5 joints) ^[1]^[2]^[3]

Infectious
- Viral arthritis (e.g., due to parvovirus B19, HCV, HBV, or HIV)
- Rheumatic fever
- Infective endocarditis (immune complex-mediated)
- Disseminated gonococcal infection (arthritis-dermatitis syndrome)
Autoimmune or inflammatory
- Rheumatoid arthritis
- Systemic lupus erythematosus (SLE)
- Juvenile idiopathic arthritis (polyarticular subtype)
- Adult-onset Still disease
- Thyroid disorders
- Lofgren syndrome
- Systemic vasculitis (e.g., IgA vasculitis, cryoglobulinemic vasculitis)
- Idiopathic inflammatory myopathies
Other
- Hand osteoarthritis
- Paraneoplastic arthritis (e.g., due to leukemia, lymphoma, or multiple myeloma) ^[1]^[4]
- Drug-induced arthritis (e.g., due to quinolones, DPP-4 inhibitors, or aromatase inhibitors) ^[1]^[2]^[4]

The most common causes of polyarthritis are hand osteoarthritis and rheumatoid arthritis. ^[2]

Common causes by pattern and course

Oligoarthritis and polyarthritis by pattern and course
	Symmetrical	Asymmetrical
Acute (< 6 weeks)	Viral arthritis (e.g., due to parvovirus B19, HCV, HBV, or HIV) Acute rheumatic fever	Reactive arthritis Gonococcal arthritis Gout or pseudogout Lyme arthritis
Chronic (≥ 6 weeks)	Rheumatoid arthritis SLE Chronic viral arthritis (e.g., due to chronic hepatitis C)	Psoriatic arthritis Enteropathic arthritis Seronegative spondyloarthropathy with peripheral involvement Chronic reactive arthritis Osteoarthritis

Clinical evaluation

Focused history ^[2]^[4]^[5]

Joint symptoms
- Onset and duration
- Number of affected joints
- Specific joints affected
  - Small (e.g., MCPs, proximal interphalangeal joints) vs. large (e.g., knees, shoulders)
  - Axial skeleton involvement: See also “Seronegative spondyloarthropathies.”
- Inflammatory features: morning stiffness (including duration), gelling, symptoms of synovitis (e.g., warmth, erythema, swelling, tenderness)
- Pattern of involvement
Extra-articular and/or systemic symptoms
- Systemic: fever, chills, fatigue, weight loss
- Skin: rashes, nodules, nail changes
- Eyes: redness, pain, vision changes
- Gastrointestinal: abdominal pain, diarrhea, mouth ulcers
- Genitourinary: dysuria, urethral discharge
- Respiratory: dyspnea, cough, pleurisy
- Neurological: weakness, paresthesia
- Other: Raynaud phenomenon, sicca syndrome
Past medical history: potential causes of polyarthritis or oligoarthritis
- Recent infectious diseases (e.g., urethritis, acute pharyngitis)
- Diagnosed autoimmune conditions (e.g., SLE, inflammatory bowel disease, psoriasis)
- Cancer
Medications: medication review with a focus on new medications
Family history: autoimmune conditions (e.g., rheumatoid arthritis, ankylosing spondylitis, SLE)
Social history: intravenous drug use, STIs, exposures (e.g., tick bites, recent travel)

Infectious causes of polyarthritis (e.g., viral arthritis, rheumatic fever) are typically acute in onset. ^[2]

Focused examination ^[1]^[2]^[3]^[4]

Musculoskeletal examination

Inspection
- Swelling
- Erythema
- Deformities
- Muscle atrophy
Palpation
- Warmth
- Tenderness (e.g., at the joint line or entheses)
- Synovial thickening
Range of motion (active and passive)
- Degree of reduction
- Pain with movement
Joint assessment
- Number of affected joints (i.e., oligoarthritis vs. polyarthritis)
- Peripheral (e.g., hands, feet, knees) vs. axial (e.g., spine, sacroiliac joints)
- Predominant joints affected (i.e., small or large joints)
- Pattern of involvement (i.e., migratory, additive, or intermittent)
- Symmetrical vs. asymmetrical arthritis

Synovitis is a typical feature of inflammatory polyarthritis or oligoarthritis (e.g., infections, autoimmune conditions, gout, CPPD disease) but is usually mild or absent in patients with osteoarthritis.

Thoracolumbar and/or sacroiliac joint involvement commonly occurs in ankylosing spondylitis, psoriatic arthritis, enteropathic arthritis, and reactive arthritis but is rare in rheumatoid arthritis. ^[2]

Extra-articular examination

Skin: rashes, nodules, ulcers, nail changes (e.g., pitting, onycholysis)
Eyes: conjunctival injection, signs of uveitis (e.g., ciliary flush, photophobia)
Oropharynx: ulcers, dryness
Neck: lymphadenopathy, palpable thyroid gland
Cardiovascular: heart murmurs, pericardial friction rub
Lungs: pathological breath sounds
Abdomen: tenderness, organomegaly
Neurological: motor function examination, focused sensory examination

Extra-articular features suggest an autoimmune or inflammatory cause of oligoarthritis or polyarthritis.

Swan neck deformity Boutonniere deformity Differential diagnosis: hand joint pain Malar rash Plaque psoriasis Rheumatoid nodules Subcutaneous nodules in rheumatic fever Erythema migrans in Lyme disease Dactylitis

Diagnostics

General principles

In most patients with oligoarthritis or polyarthritis, a probable cause is identified during clinical evaluation.
- Tailor the diagnostic approach to the suspected condition (e.g., diagnostics for rheumatoid arthritis).
- For undifferentiated arthritis, obtain laboratory studies and imaging listed below.
Early referral to specialists (e.g., rheumatology, infectious diseases) improves clinical outcomes.

Approximately 30% of patients with early inflammatory arthritis are eventually diagnosed with rheumatoid arthritis. ^[6]

Initial studies ^[2]^[3]^[5]

Synovial fluid analysis

Indication: all patients with suspected septic arthritis (e.g., gonococcal arthritis)
Procedure: See “Arthrocentesis steps.”
Additional considerations
- Consider specialist input prior to arthrocentesis in patients receiving anticoagulants.
- Consider inoculating synovial fluid into blood culture bottles to improve the sensitivity of cultures. ^[7]

Do not delay joint aspiration in suspected septic arthritis; early detection and treatment are imperative to prevent cartilage destruction. ^[7]

Laboratory studies

CBC: may show leukocytosis, anemia of chronic inflammation associated with a systemic condition
Inflammatory markers (nonspecific study): may be elevated in infectious, malignant, autoimmune, or chronic conditions
BMP: ↑ creatinine and BUN in systemic conditions with kidney involvement (e.g., SLE, systemic sclerosis)
Liver chemistries: may be elevated in viral hepatitis or in autoimmune or inflammatory conditions with liver involvement
Urinalysis: Active urine sediment and/or proteinuria may be present in systemic conditions with renal involvement (e.g., SLE).
Serology: serologic testing in RA, ANAs for SLE in patients with constitutional symptoms and extra-articular features

Carefully consider the clinical indication before requesting any diagnostic study to avoid false positives; autoantibodies may be elevated in healthy individuals. ^[1]

X-rays

Obtain x-rays of the affected joints.

Hand x-ray
- See “Imaging studies” in “Rheumatoid arthritis.”
- See “Imaging studies” in “Osteoarthritis.”
- See “Imaging studies” in “Psoriatic arthritis.”
Spine x-ray: if spinal involvement is suspected (e.g., in psoriatic arthritis, ankylosing spondylitis)
Chest x-ray: in patients with pathological breath sounds, dyspnea, or other cardiopulmonary signs

Additional studies ^[2]^[3]^[5]

Obtain additional studies based on the suspected cause.

Serology, e.g.:
- HBV serology and HCV serology for viral arthritis
- Lyme disease serology
Additional imaging studies, e.g.:
- Joint ultrasound (e.g., MCP joints): to assess for subclinical synovitis if early rheumatoid arthritis is suspected ^[1]^[8]
- MRI of affected joints: if osteomyelitis is suspected in septic arthritis
- HRCT chest: if pulmonary involvement is suspected in systemic conditions
- Echocardiography: to assess for conditions to assess for cardiac involvement (e.g., endocarditis, pericarditis)

Rheumatoid arthritis of the wrist and hand Erosive osteoarthritis of the hand Psoriatic arthritis Bamboo spine and dagger sign in ankylosing spondylitis Synovial proliferation and inflammation in rheumatoid arthritis

Common causes

Common causes of oligoarthritis and polyarthritis ^[2]^[3]^[4]
Condition	Characteristic clinical features	Diagnostic findings	Management approach
Rheumatoid arthritis	Symmetrical polyarthritis Predominantly affects peripheral joints (e.g., MCP joints, PIP joints, knee joints); DIP joints are usually spared. Additive arthritis pattern Morning stiffness (lasting > 30 minutes) Synovitis, positive compression test Extra-articular features, e.g.: Rheumatoid cutaneous nodules Interstitial lung disease (ILD), episcleritis, tenosynovitis, Raynaud phenomenon	Positive rheumatoid factor and/or ACPA X-rays (hands): joint space narrowing, marginal bone and cartilage erosions, subchondral cysts Ultrasound: synovial hyperemia and/or proliferation	DMARDs (e.g., methotrexate) Symptomatic treatment: systemic glucocorticoids, NSAIDs, and/or selective COX-2 inhibitors Refer to rheumatology. See “Management of RA.”
Hand osteoarthritis	Asymmetrical polyarthritis Affects small joints (e.g., DIP and PIP joints) Pain and stiffness are worse with activity. Heberden nodes and Bouchard nodes Usually no synovitis No extra-articular features	Normal laboratory findings X-rays (hands): irregular joint space narrowing, osteophytes	Symptomatic treatment: topical or oral NSAIDs Physical therapy See “Management of osteoarthritis.”
SLE	Symmetrical polyarthritis or oligoarthritis Predominantly affects hand joints (e.g., MCP joints, PIP joints, DIP joints), knee joints Additive arthritis pattern Morning stiffness Extra-articular features are common (e.g., constitutional symptoms, malar rash, serositis, lupus nephritis).	Positive ANAs, anti-dsDNA antibodies, anti-Sm antibodies ↓ C3 and/or C4 Leukopenia, thrombocytopenia	Hydroxychloroquine Refer to rheumatology. See “Management of SLE.”
Viral arthritis	Symmetrical polyarthritis Predominantly affects small joints Acute onset Extra-articular features (e.g., fever, rash)	Clinical diagnosis Positive serology (e.g., HIV serology, hepatitis C serology)	Symptomatic treatment (e.g., NSAIDs) Usually self-limited See also: “Hepatitis B” “Hepatitis C” “Rubella” “Parvovirus B19-associated arthritis” “HIV-associated arthritis”
Psoriatic arthritis	Symmetrical polyarthritis or asymmetrical oligoarthritis Predominantly affects peripheral joints (e.g., DIP and PIP joints) but may also affect the spine Additive arthritis pattern Extra-articular features, e.g.: Nail pitting and/or onycholysis ^[9]^[10] Dactylitis and/or clinical features of psoriasis	Negative rheumatoid factor and ACPA X-rays (hands): pencil-in-cup deformity X-rays (spine): syndesmophytes between vertebral bodies, unilateral sacroiliitis	NSAIDs (e.g., naproxen, indomethacin) DMARDs (e.g., methotrexate, tofacitinib, etanercept) Refer to rheumatology. See “Management of psoriatic arthritis.”
Reactive arthritis	Asymmetrical oligoarthritis or polyarthritis Acute onset Migratory arthritis pattern Predominantly affects lower extremity joints Sacroiliitis, enthesitis Extra-articular features, e.g.: Dactylitis Conjunctivitis, oral ulcers Cardiac involvement Urethritis	Clinical diagnosis Symptoms of prior infection (e.g., diarrhea, UTI symptoms) If features atypical, exclude other causes (e.g., using synovial fluid analysis, RA serology). Positive culture HLA-B27 (not routinely recommended) ^[11]^[12]	Treat active infections. Symptomatic management: NSAIDs or glucocorticoids DMARDs (e.g., sulfasalazine, methotrexate): for chronic (> 6 months) or severe reactive arthritis Refer patients with extra-articular involvement to specialists (e.g., ophthalmology, cardiology). See “Management of reactive arthritis.”
Enteropathic arthritis	Symmetrical polyarthritis or asymmetrical oligoarthritis Peripheral or axial involvement Extra-articular features, e.g.: Symptoms of IBD (e.g., symptoms of Crohn disease or ulcerative colitis) Nail clubbing Uveitis, oral ulcers Erythema nodosum	Features of IBD (e.g., symptoms of Crohn disease or ulcerative colitis) Imaging: sacroiliitis or spondylitis	Glucocorticoids and other immunosuppressants (e.g., anti-TNF-α agents, azathioprine) Refer to rheumatology and gastroenterology. See also: “Management of Crohn disease” “Management of ulcerative colitis”
Ankylosing spondylitis	Asymmetrical oligoarthritis Predominantly affects the sacroiliac joints but may also affect the hip, shoulder, and/or knee Inflammatory back pain Extra-articular features, e.g.: Constitutional symptoms Inflammatory enthesitis (e.g., in the calcaneal tendon, iliac crests) Dactylitis Anterior uveitis, IBD, ILD	Positive HLA-B27 (in up to 95% of patients with axial involvement) ^[13]^[14] X-rays (sacroiliac joints): increased radiopacity of the sacroiliac joints X-rays (spine): intervertebral and/or costovertebral ankylosis, syndesmophytes between vertebral bodies	Physical therapy Pharmacotherapy for ankylosing spondylitis (e.g., local glucocorticoids, NSAIDs, etanercept, sulfasalazine) Surgery (e.g., hip arthroplasty, spinal osteotomy) in patients with severe functional impairment See “Management of ankylosing spondylitis.”

Rheumatoid arthritis Distribution pattern: rheumatoid arthritis of the hand Rheumatoid cutaneous nodules Rheumatoid arthritis of the wrist and hand Synovial proliferation and inflammation in rheumatoid arthritis Heberden and Bouchard nodes Distribution pattern of osteoarthritis of the hand Erosive osteoarthritis of the hand Psoriatic arthritis Distribution pattern: psoriatic arthritis of the hand

Mimics

Systemic conditions ^[2]
Other

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