• antibiotics;
  • chronic plaque psoriasis;
  • guttate psoriasis;
  • streptococcal infection;
  • tonsillectomy

Background Guttate psoriasis is closely associated with preceding or concurrent streptococcal infection. Some authorities have claimed that chronic plaque psoriasis may also be made worse by infection. In view of this many dermatologists have recommended using antibiotics for psoriasis, particularly guttate type. Some dermatologists have also recommended tonsillectomy for psoriasis in patients with recurrent streptococcal pharyngitis.

Objectives This review aims to assess the evidence for the effectiveness of antistreptococcal interventions, including antibiotics and tonsillectomy in the management of acute guttate and chronic plaque psoriasis.

Methods Studies were identified by searching 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.

Results Only one trial met the selection criteria. This compared the use of two oral antibiotic schedules in 20 psoriasis patients, predominantly of guttate type, who had evidence of β-haemolytic streptococcal colonization. Either rifampicin or placebo was added to the end of a standard course of phenoxymethylpenicillin or erythromycin. No patient in either arm of the study improved during the observation period. No randomized trials of tonsillectomy for psoriasis were identified.

Conclusions Although both antibiotics and tonsillectomy have frequently been advocated both for patients with guttate psoriasis and for selected patients with chronic plaque psoriasis, there is to date no good evidence that either intervention is beneficial.