REACTIVE ARTHRITIS (REITER’S
SYNDROME)
Reactive arthritis (formerly known as Reiter’s syndrome) comprises a unique constellation of clinical findings. The syndrome is believed to be precipitated by an infectious agent, often shigella or chlamydia.
Clinical Findings: Reactive arthritis usually affects men in the third to fifth decades of
life. The most frequent skin findings are balanitis circinata and keratoderma
blennorrhagica. Balanitis circinata manifests as small psoriasiform,
pink-to-red patches on the glans penis. It can appear identical to psoriasis.
Keratoderma blennorrhagicum is less common than balanitis circinata. It occurs
on the soles and palms, with the soles predominating. Small papulosquamous
papules, patches, and plaques occur on the glabrous skin. Small, juicy papules
and pustules can be scattered throughout the involved skin; the clinical
appearance can mimic psoriasis. Some scholars think that reactive arthritis and
psoriasis are one in the same, but other clinical findings of reactive
arthritis make the two worthy of differentiation. The unique clinical hallmarks
that separate reactive arthritis from psoriasis are the triad of urethritis, conjunctivitis,
and arthritis. Urethritis typically is the initial clinical finding. It often
begins a few days to 1 week after an infection. The infective agent that most
commonly precipitates this syndrome is Chlamydia trachomatis.
Gas-trointestinal bacterial infections have also been shown to initiate the
reaction, including infections with Shigella flexneri, Salmonella species,
Yersinia enterocolitica, and Campylobacter jejuni. Dysuria,
urinary frequency, and pyuria can be the presenting findings. Women with severe
urethritis can develop cervicitis, cystitis, and pyelonephritis. Men are prone
to development of cystitis and prostatitis. A few days to weeks later, the
affected patient develops conjunctivitis and arthritis. The conjunctiva is red
and injected with a weeping exudate. Iritis and uveitis are rarely seen
manifestations but can occur. Reactive arthritis is considered to be a
seronegative form of arthritis. It is typically polyarticular and affects the
large joints such as the knees and hips. The joints become swollen, red, and
tender. Movement can be restricted because of pain. Most cases spontaneously
resolve, but a subset of patients develop chronic progressive destructive
arthritis.
Some patients develop nondescript small, discrete oral
ulcers that can appear the same as aphthous ulcers. They can be nontender, and
this feature can be helpful in differentiating them from other forms of oral
ulcers. These ulcers spontaneously resolve in most cases. Laboratory testing
show seronegativity. Testing for both the rheumatoid factor and antinuclear
antibodies (ANA) is negative. The sedimentation rate is often extremely
elevated. Patients frequently carry the human leukocyte antigen (HLA)-B27
marker. This is a marker that has been found to occur with a higher than
expected frequency in patients with ankylosing spondylitis and reactive
arthritis. However, most patients who test positive for the HLA-B27 marker
never develop either of these conditions. There is no blood test that can make
the diagnosis of reactive arthritis. Radiographs can be helpful in assessing
joint inflammation and joint destruction. The diagnosis of reactive arthritis
is made on clinical grounds. Most patients do not exhibit all of the findings
mentioned, and the diagnosis is based on the number of clinical findings and
the length of time the patient has had them. The American College of
Rheumatology has published complicated criteria to help make the diagnosis.
Pathogenesis: The leading
theory is that an infection in a susceptible individual sets off this
immunological reaction. HLA-B27 seems to be a marker that is frequently
positive in patients with reactive arthritis, but only a small subset of
HLA-B27–positive patients develop the disease. The exact pathomechanism is
unknown. Possibly, a bacterial antigen causes epitope spreading and initiates
the autoimmune reaction.
Histology: The
pathological findings are nondiagnostic and appear identical to those of
psoriasis. Psoriasiform hyperplasia of the epidermis is prominent, along with neutrophils. Increased numbers of blood vessels
are seen in the dermis.
Treatment: Any underlying
infection must be sought and appropriately treated with the correct antibiotic
therapy. Nonsteroidal antiinflammatory drugs are used to treat the arthritis.
An ophthalmologist should be consulted to evaluate the globe. Corticosteroid
eye drops are frequently used. Topical steroids can be used to treat the skin
manifestations. Many patients experience a spontaneous remission in a few months.
