The clinical spectrum of Reiter's syndrome and similar postenteric arthropathies.

Certain infections of the genitourinary and gastrointestinal tracts, such as nongonococcal urethritis, dysentery and yersiniosis, precipitate characteristic arthritic syndromes in genetically susceptible individuals. Eye and skin lesions in the form of conjunctivitis, iritis, keratodermia blenorrhagica and erythema nodosum occurring in association with particular distributions of arthritis make recognizable clinical entities. Reiter's syndrome may be diagnosed with certainty from the presence of tender heels, low back pain, a predominance of knee and foot arthritis and pyuria, when the more obvious clinical markers of the syndrome are absent; a flagrant case represents one of the easiest clinical diagnoses in medicine. Diagnosis is important for a good prognosis, optimal treatment and sometimes prophylactic measures. Sacroiliitis often progressing to spinal ankylosis is a prominant feature in the B27-positive patient. Erythema nodosum occurs in B27-negative subjects as a response to yersiniosis and ulcerative colitis.