Cercarial
dermatitis, a re-emerging disease world-wide, may affect those engaged in water sports. Many of those who swim in the annual cross-lake races at Annecy in France, for example, develop such
dermatitis. In an attempt to see whether ethyl butylacetylaminopropionate (
IR3535) would protect swimmers from the
dermatitis, the exposed skin on the right side of each of 78 participants in the cross-lake races of 2001 was treated with IR3535-based
ointment. When contacted by telephone during the week following the races, 64 (82%) of the subjects reported that they had developed cercarial
dermatitis. Subjects with a past history of cercarial
dermatitis were more likely to report an attack in 2001 than those who said that they had never had such
dermatitis prior to 2001 (P=0.001). The skin lesions were scattered all over the body in 89% of the cases and limited to the left side of the body in 11%. Of the 63 cases who reported time of onset, 32 (51%) had noticed lesions within an hour of the race. The mean duration of clinical manifestations was 4.8 days (range=30 min-18 days). The clinical manifestations were significantly more severe in the subjects aged >16 years than in the younger subjects, although these two age-groups swam in separate races. Thirty-one of the affected subjects attempted to cure their
dermatitis, using any of five different treatments. Overall, the results were disappointing, with the IR3535-based
ointment, which had initially been developed as an
insect repellent, appearing to offer little, if any, protection against cercarial
dermatitis.