Differentiating reactive arthritis from other diseases

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Reactive arthritis should be distinguished from other HLA-B27 diseases causing arthritis of the peripheral skeleton, which present as arthralgia. The differentials include psoriatic arthritis, rheumatoid arthritis and ankylosing spondylitis.

Differentiating Reactive Arthritis from other Diseases

Reactive arthritis should be distinguished from other diseases causing arthritis of the peripheral skeleton, which present as arthralgia. The differentials include:

Arthritis Type	Clinical Features						Body Distribution				Key Signs				Laboratory Abnormalities
	Symmetric joint involvement	Asymmetric joint involvement	Enthesopathy	Dactylitis	Nail Dystrophy	Human immunodeficiency virus association	Upper extremity-hands	Lower extremity	Sacroiliac joints	Spine	Osteopenia	Joint Space	Ankylosis	Periostitis	Soft tissue swelling	ESR	Rheumatoid factor (RF)	HLA-B27
Reactive arthritis (Reiter's syndrome)	+++	-	+	+	-	-	++	+++	++ (Unilateral)	+	+	+ (Narrowing)	-	+++ (Fluffy)	++	++	-	75%
Psoriatic arthritis	+	++	+	+	+	+	+++ (DIP/PIP)	+++	++ (Unilateral)	++	-	++ (Widening)	++	+++ (Fluffy)	++	+	-	30-75%
Rheumatoid arthritis	++	+	-	-	-	-	+++ (MCP/wrist)	+++	+ (Unilateral)	++(Cervical)	+++	+++ (Narrowing)	+	+ (Linear)	+++	+++	+++	6-8%
Ankylosing spondylitis	+++	-	+	-	-	-	+	+	+++ (Bilateral)	+++	+++	++ (Narrowing)	+++	+++ (Fluffy)	+	+++	-	90%

Key:+ : Infrequently present, ++ : Frequently present, +++ : Always present, - : Absent

Reactive arthritis must be differentiated from other causes of rash and arthritis

Disease	Findings
Reactive arthritis (Reiter syndrome)	Musculoskeletal manifestation include arthritis, tenosynovitis, dactylitis, and low back pain. Extraarticular manifestation include conjunctivitis, urethritis, and genital and oral lesions. Reactive arthritis is a clinical diagnosis based upon the pattern of findings and there is no definitive diagnostic test
Nongonococcal septic arthritis	Presents with an acute onset of joint swelling and pain (usually monoarticular) Culture of joint fluid reveals organisms
Acute rheumatic fever	Presents with polyarthritis and rash (rare presentation) in young adults. Microbiologic or serologic evidence of a recent streptococcal infection confirm the diagnosis. Poststreptococcal arthritis have a rapid response to salicylates or other antiinflammatory drugs.
Syphilis	Presents with acute secondary syphilis usually presents with generalized, pustular lesions at the palms and soles with generalized lymphadenopathy Rapid plasma reagin (RPR), Venereal Disease Research Laboratory (VDRL) and Fluorescent treponemal antibody absorption (FTA-ABS) tests confirm the presence of the causative agent.
Hepatitis B virus (HBV) infection	Presents with fever, chills, polyarthritis, tenosynovitis, and urticarial rash Synovial fluid analysis usually shows noninflammatory fluid Elevated serum aminotransaminases and evidence of acute HBV infection on serologic testing confirm the presence of the HBV.
Herpes simplex virus (HSV)	Genital and extragenital lesions can mimic the skin lesions that occur in disseminated gonococcal infection Viral culture, polymerase chain reaction (PCR), and direct fluorescence antibody confirm the presence of the causative agent.
HIV infection	Present with generalized rash with mucus membrane involvement, fever, chills, and arthralgia. Joint effusions are uncommon
Gout and other crystal-induced arthritis	Presents with acute monoarthritis with fever and chills Synovial fluid analysis confirm the diagnosis.
Lyme disease	Present with erythema chronicum migrans rash and monoarthritis as a later presentation. Clinical characteristics of the rash and and serologic testing confirm the diagnosis.

References

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