Details of systematic review undertaken for the guideline

The evidence base for this guideline was synthesised in accordance with SIGN methodology. A systematic review of the literature was carried out using an explicit search strategy which was based on the Cochrane search strategy.

Papers were only included if they adhered to recognisable methodological principles, including adequate sample size, a clearly identified hypothesis and measure of outcome, and accurate reporting of results. Whenever possible randomised trials have been discussed, but due to the paucity of sound randomised controlled trials work in this area, a number of clinical studies have also been included.

Literature Search Strategy

The standard SIGN methodology was followed using searches of the Cochrane database, Medline, Healthstar and Embase for randomised controlled trials using the keywords: tonsillitis, tonsils, sore throat, pharyngitis, tonsillectomy. For epidemiology, microbiology and pathology, references were obtained using a broad strategy linking the terms (`tonsillitis' or `pharyngitis') with (`epidemiology' or `microbiology' or `pathology'). The resulting set was combined with terms identifying meta-analysis, RCTs or other good quality clinical trials. The search was run on the following databases:

• Embase 1974-96
• Science Citation Index (SCI SEARCH)
• 1987-96 Pascal 1974-96
• US Technical Information Service 1964-96
• Conference Papers Index 1973-96
• Inside Conferences 1993-96.

The principal terms were also checked against the applied social sciences, social science citation index and sociological abstracts databases, but did not reveal any additional literature of interest. The evidence base for the guideline was updated during the course of the guideline development process to take into account newly published evidence.