Case description:
A 30-year-old man presented to the rheumatology department with a 20-day-history of inflammatory arthralgia. He had no medical history and was a smoker.
The patient claimed to have had a urethral discharge one month before the onset of articular manifestations. He also reported having non-protected sexual intercourse.
Physical examination showed left knee joint effusion, synovitis of metacarpophalangeal joints, and proximal interphalangeal (PIP) joints.
The left sacroiliac joint was tender with positive compression, distraction, and sacral thrust provocation tests. The patient also had right third finger dactylitis (figure 1) and plantar papulosquamous plaques (figure 2).
The patient had no fever, urethritis, conjunctivitis, or uveitis.
Laboratory examinations reveal increased C-Reactive protein (CRP) level (97 mg/L, Normal value (N) <8 mg/L), elevated erythrocyte sedimentation rate (ESR) (83 mg/L, N<15 mm). Liver and renal tests were within the normal range.
Anti-nuclear antibodies, rheumatoid factor, and anti-citrullinated protein antibodies were negative.
Polymerase chain reaction (PCR) test for Chlamydia trachomatis (Ct) and Gonococcus in the first catch urine specimen were negative. Detection of Ct by PCR in blood sample was also negative. Hepatitis B and C, Ct, Human Immunodeficiency Virus, and syphilis serologic test results were negative.
The human leukocyte antigen (HLA) B27 was positive. Radiographs of hands and feet did not reveal erosions or joint space narrowing.
The pelvis radiograph did not show sacroiliitis. Pelvic magnetic resonance imaging (MRI) revealed subchondral bone marrow edema of the left sacroiliac joint attesting to an active inflammation of sacroiliac joints.
The diagnosis of ReA was made based on the history of urethral discharge preceding rheumatological manifestations associated with plantar papulosquamous plaques, dactylitis, and the positivity of HLA-B27.
Ceftriaxone (a single dose of 1 g) and doxycycline (200 mg daily for three months) were indicated. Sulfasalazine (2 grams daily) and diclofenac (150 mg daily) were also prescribed, leading to the alleviation of clinical manifestations.
Plantar skin lesions regressed on the third day of antibiotic therapy.
After six months of follow-up, Bath ankylosing spondylarthritis disease activity index (BASDAI) [5] fell from 4.9 to 2.1. Inflammatory biomarkers became within the normal range.