Caroline M Owen, Robert Chalmers, Teresa O'Sullivan, Christopher EM Griffiths

Guttate psoriasis is a distinctive acute form of psoriasis which characteristically occurs in children and young adults. It is closely associated with preceding streptococcal sore throat or tonsillitis. Some authorities have claimed that ordinary (chronic plaque) psoriasis may also be made worse by infection at distant sites. Although many dermatologists have recommended using antibiotics for guttate psoriasis in particular, it is not clear whether they influence the course of either form of psoriasis. Some dermatologists have also recommended tonsillectomy for psoriasis in patients with recurrent streptococcal sore throat. To assess the evidence for effectiveness of antistreptococcal interventions including antibiotics and tonsillectomy in the management of acute guttate and chronic plaque psoriasis. We searched the Cochrane Clinical Trials Register (Cochrane Library, Issue 3, 1999), Medline (1966- September 1999), Embase (1988-September 1999), the Salford Database of Psoriasis Trials (to November 1999) and the European Dermato-Epidemiology Network (EDEN) Psoriasis Trials Database (to November 1999) for terms [STREPTOCOCC* or ANTIBIOTIC* or TONSIL*] and PSORIASIS using the Cochrane Skin Group search strategy. Randomised trials of one or more antistreptococcal interventions in patients with guttate or chronic plaque psoriasis. Two reviewers independently examined each retrieved trial for eligibility and quality. The one eligible trial we identified compared the use of two oral antibiotic schedules in 20 psoriasis patients, predominantly of guttate type, who had evidence of beta-haemolytic streptococcal colonisation. Either rifampicin or placebo was added to the end of a standard course of antistreptococcal antibiotic (phenoxymethylpenicillin or erythromycin). No patient in either arm of the study improved during the observation period. No randomised trials of tonsillectomy for psoriasis were identified. Although it is well known that guttate psoriasis may be precipitated by streptococcal infection, there is no firm evidence to support the use of antibiotics either in the management of established guttate psoriasis or in preventing the development of guttate psoriasis following streptococcal sore throat. Although both antibiotics and tonsillectomy have frequently been advocated for patients with recurrent guttate psoriasis or chronic plaque psoriasis, there is to date no good evidence that either intervention is beneficial.