[External otitis in school children after an intensive swimming course.]

This study reports an outbrake of external otitis in boarding school children after they had participated in an intensive swimming course. The infective agent isolated was P. aeruginosa. The question is raised whether the outbrake was caused by water contaminated by bacteria or intensive bathing.

Twenty-seven children from a rural boarding school, aged 10 to 14 years participated in an obligatory swimming course for two weeks. As the outbrake became evident all the children were examined by two doctors with an otomicroscope. Bacterial culture was taken from the external acoustic meatus (EAM) on both sides and a tympanogram was performed on all. Subjective evaluation of symptoms was achieved by using a questionnaire. Eight weeks after the swimming course ended all participants were investigated again with an ear microscope and control bacterial culture was taken from the EAM for appreciation of the outcome.

Seventeen (63%) of the 27 children had symptoms of external otitis on the first visit. Microscopic investigation of those infected revealed seven (41.2%) children with mild, four (23.5%) with mode notrate and six (35.3%) with severe inflammation of the EAM. Of those children affected 12 (70.6%) had infection in both ears. P. aeruginosa was isolated from 11(64,7%) of those affected and from two of those who had no symptoms. The mean onset of symptoms was 2.1 days (standard error 0.5) after the swimming course had ended. The mean time for symptom relief was 11.4 days (standard error 2.2).

Intensive swimming courses in pools where the quality of the water is checked sporadically is not advised. If intensive swimming courses are necessary the concentration of chlorine should be carefully monitored as well as checked for growth of both Cloriform bacteria and P. aeruginosa.