The association between impetigo, insect bites and air temperature: a retrospective 5-year study (1999-2003) using morbidity data collected from a sentinel general practice network database

BACKGROUND: Impetigo is one of the commonest childhood skin infections. Insect bites are commonly implicated in the development of impetigo. There are, however, very few data available to describe the seasonal incidences and association between the two conditions. OBJECTIVES: To describe the seasonal incidence of impetigo in England and Wales and to investigate the reported association with insect bites. METHODS: Clinical diagnoses of impetigo and insect bites were recorded from a sentinel GP network over the years 1999-2003. RESULTS: The highest mean weekly rates of impetigo were in children aged 0-4 years (84 per 100 000) and in those aged 5-14 years (54 per 100 000). In contrast, the incidence of insect bite only varied between 3 and 5 per 100 000 for males and between 5 and 9 per 100 000 for females. The relative risk (RR) for females consulting over males with impetigo was similar in children [RR 0.99 (95% CI 0.96-1.02)] and adults [RR 1.20 (1.16-1.25)]; the RR of insect bite was similar in children [RR 1.21 (1.09-1.34)] but almost twice as likely in adults [RR 2.13 (2.02-2.25)]. Insect bite peaked almost coincidentally with temperature whereas there was a lag of one-to-two 4-week periods between impetigo and temperature. CONCLUSION: There is suggestion of some degree of association between impetigo and insect bites. The improved management of patients consulting with insect bites and better use of antiseptic treatments might provide the basis for reducing the incidence of impetigo in the community.