ABC of Rheumatology: RASHES AND VASCULITISBMJ 1995; 310 doi: https://doi.org/10.1136/bmj.310.6987.1128 (Published 29 April 1995) Cite this as: BMJ 1995;310:1128
- R A Watts,
- D G I Scott
Many patients with rheumatological disorders either present with a rash or develop a rash in the course of the disease. This is particularly true of the connective tissue diseases and psoriasis, which have been described elsewhere in this series. The differential diagnosis of rash and arthritis is wide, but in most cases a diagnosis can be made on the basis of history, clinical examination, and appropriate blood tests.
Differential diagnosis of rash and arthritis
Juvenile chronic arthritis
Connective tissue disease
Common infectious causes of rash and arthritis
Several microorganisms can cause both a rash and arthritis, either by direct infection or by immune mediated mechanisms.
Rheumatic fever is caused by an immune mediated response to group A ß haemolytic streptococcal pharyngitis. It is rare in the developed world, but recent outbreaks have been reported in the United States and Europe. Most cases occur in people aged 5-16. The characteristic skin lesion is erythema marginatum. The arthritis affects large joints and migrates from joint to joint, each joint being affected for only two to three days, and lasts overall for three weeks. Nodules may develop over bony prominences; other features include chorea and carditis. Infections are treated with penicillin and anti-inflammatory drugs.
A reactive arthritis can occur after infections with group A and possibly group G streptococci. The arthritis is more prolonged, lasting for two to three months, and does not migrate between joints. It may be accompanied by a vasculitic rash.
Disseminated infection with Neisseria gonorrhoea is three to five times more common in women than men. Urethritis or cervicitis is often asymptomatic. There is an initial bacteraemic phase with a migratory polyarthritis and typical skin …