The archetypal inflammatory spondyloarthropathy, ankylosing spondylitis, causes inflammatory low back pain frequently presenting in young men. Ninety-five per cent of those affected will carry the human leucocyte antigen (HLA) B27 genotype. The occupational management of this condition is described in Chapter 12.
The seronegative arthritides are a group of clinical conditions which share in common seronegativity for rheumatoid factor and certain clinical, epidemiological, and genetic features— e.g. asymmetrical joint involvement, sacro-iliac joint involvement, risk of anterior uveitis, variable association with HLA B27, skin involvement (prominent in psoriatic arthritis), mucosal involvement (urethritis, conjunctivitis), enthesitis, and a variable association with bacteria or bacterial products.
In most cases, reactive arthritis is an acute event, triggered by infection with a causative organism. Although patients may present feeling extremely unwell and with several hot, red inflamed joints, providing the diagnosis is made promptly and appropriate treatment initiated for the causative organism, most cases settle within 6 weeks and the vast majority within 6 months. The prognosis is good and long-term disease-modifying therapy is not required. During the acute phase, the patient may require hospital admission or intensive outpatient management coupled with rest but in the long term, full functional restoration and return to work fitness can be expected.