Arthritis, Reactive

KEY FEATURES

Essentials of Diagnosis

• Oligoarthritis, conjunctivitis, urethritis, keratoderma blennorrhagicum, and mouth ulcers

• Usually follows dysentery or a sexually transmitted infection

• HLA-B27–positive in 50–80% of patients

General Considerations

• Reactive arthritis

  • Precipitated by antecedent gastrointestinal (GI) or genitourinary infections

  • Manifests as an asymmetric sterile oligoarthritis, typically of the lower extremities

  • Affected joints are sterile

  • Antigens (and DNA in the case of Chlamydia) from putative inciting organisms, however, may be present in synovial tissue based on molecular techniques

    • Even years after the clinical disease

    • Pathogenic significance of these findings remains unclear

• Frequently associated with enthesitis

• Extra-articular manifestations are common and include

  • Urethritis

  • Conjunctivitis

  • Uveitis

  • Keratoderma blennorrhagicum

  • Mucocutaneous lesions

Demographics

• Most common in young men

• Associated with HLA-B27 in 80% of White patients and 50–60% of Black patients

CLINICAL FINDINGS

Symptoms and Signs

• Most cases develop within 1–4 weeks after either a GI infection (usually with Shigella, Salmonella, Yersinia, or Campylobacter) or a sexually transmitted infection (with Chlamydia trachomatis or perhaps Ureaplasma urealyticum)

• Other pathogens known to cause reactive arthritis include Mycobacterium, Streptococcus, Staphylococcus, and SARS-CoV-2

• Arthritis is most commonly asymmetric and frequently involves the large weight-bearing joints (chiefly the knee and ankle)

• Sacroiliitis or ankylosing spondylitis is observed in at least 20% of patients, especially after frequent recurrences

• Systemic symptoms including fever and weight loss are common at the onset of disease

• Mucocutaneous lesions may include

  • Balanitis

  • Stomatitis

  • Keratoderma blennorrhagica (indistinguishable from pustular psoriasis)

• Involvement of the fingernails in reactive arthritis mimics psoriatic changes

• When present, conjunctivitis is mild and occurs early in disease course

• Anterior uveitis, which can develop at any time in HLA-B27-positive patients, is a more clinically significant ocular complication

• Carditis and aortic regurgitation may occur

Differential Diagnosis

• Gonococcal arthritis

• New-onset rheumatoid arthritis, ankylosing spondylitis, or psoriatic arthritis

• Behçet disease

DIAGNOSIS

Laboratory Tests

• Synovial fluid from affected joints is culture-negative

• HLA B-27 test is useful in diagnosis

Imaging Studies

• Radiographic signs of permanent or progressive joint disease may be seen in the sacroiliac as well as the peripheral joints

TREATMENT

Medications

• Nonsteroidal anti-inflammatory drugs (NSAIDs) have been the mainstay of therapy

• Patients who do not respond to NSAIDs may respond to the disease-modifying antirheumatic drugs (DMARDs) sulfasalazine (1 g twice daily) or methotrexate (up to 25 mg once weekly)

• Anti-tumor necrosis factor agents, which are effective in other spondyloarthropathies, may have efficacy in recent-onset disease refractory to NSAIDs and DMARDs

• For chronic reactive arthritis associated with chlamydial infection, ...