Medicine – Clinical Features of Reiter’s Syndrome

Reiter’s syndrome, now more commonly referred to as reactive arthritis, is an inflammatory arthritis that develops after certain infections, particularly gastrointestinal or genitourinary infections. It belongs to the seronegative spondyloarthritis group and has a strong association with HLA-B27, which is present in a substantial proportion of affected patients. The classic presentation consists of a triad of arthritis, conjunctivitis, and urethritis, although many patients do not develop all three features simultaneously.

Classic Triad

1. Arthropathy

The arthritis of reactive arthritis typically presents as an acute, asymmetrical oligoarthritis involving mainly the lower limbs. The knees, ankles, and feet are commonly affected, and patients may experience pain, swelling, stiffness, and reduced joint movement. Enthesitis may also occur, particularly at the heel, and some patients can develop inflammatory back pain due to sacroiliac or spinal involvement.

2. Conjunctivitis

Conjunctivitis is a common extra-articular manifestation and usually causes redness, irritation, watering, and discomfort of the eyes. It is often mild and self-limiting, although more significant ocular inflammation such as anterior uveitis can occur in some patients and may cause pain, photophobia, or blurred vision.

3. Urethritis

Urethritis is another classical feature and may present with dysuria, urinary frequency, or urethral discharge. In sexually acquired cases, the condition may follow infection with organisms such as Chlamydia trachomatis. Some patients have only mild urinary symptoms or may be asymptomatic despite preceding infection.

Other Clinical Features

1. Sacroiliitis

Inflammation of the sacroiliac joints may occur and can cause lower back or buttock pain, particularly in patients with HLA-B27 positivity. The pain is typically inflammatory in nature, often worse after rest and improved with movement.

2. Plantar Fasciitis

Plantar fasciitis may develop as part of enthesitis, which is inflammation at the site where tendons or ligaments attach to bone. Patients commonly experience pain around the heel or sole of the foot, especially during walking or after periods of rest.

3. Circinate Balanitis

Circinate balanitis is a characteristic mucocutaneous lesion involving the glans penis. It usually appears as shallow, painless, well-defined erythematous lesions and may occur even in the absence of marked urethral symptoms.

4. Keratoderma Blennorrhagicum

Keratoderma blennorrhagicum is a distinctive skin manifestation consisting of hyperkeratotic, scaly lesions, most often affecting the soles of the feet and palms of the hands. These lesions can resemble pustular psoriasis and may occur alongside other features of reactive arthritis.

5. Oral Ulceration

Patients may develop painless oral ulcers, usually involving the oral mucosa. These lesions are generally transient and may go unnoticed unless specifically looked for during examination.

6. Pericarditis

Although uncommon, pericarditis can occur as a systemic inflammatory complication. Patients may present with central chest pain that is worse on inspiration or lying flat and relieved by sitting forward. Cardiac involvement is much less common than the musculoskeletal, ocular, and genitourinary manifestations.

Key Clinical Pattern

Reactive arthritis is classically remembered by the triad of arthritis, conjunctivitis, and urethritis, with additional features such as sacroiliitis, plantar fasciitis, circinate balanitis, keratoderma blennorrhagicum, oral ulcers, and occasionally pericarditis. The condition is strongly associated with HLA-B27, particularly in patients with more persistent or axial disease.