Adverse events associated with the use of insect repellents containing N,N-diethyl-m-toluamide (DEET)

DEET is the major component of most topically applied insect repellents used in the US. The DEET Registry is a post-marketing surveillance system to provide systematic and detailed information about medical events temporally associated with DEET use.From 1995 to 2001, 296 moderate and major severity cases were included in the DEET Registry. Of these, 36 (14.5%) cases were deemed to be probably and 157 (65%) cases possibly related to DEET exposure. Insufficient data prevented determination of causality in the remaining 49 (20.2%) cases. Forty-one percent of the cases were in children 19 or younger. Forty-two percent of children experienced a seizure of moderate or major severity.The widely variable spectrum of other neurological symptoms reported in the Registry makes it unlikely they were due to one agent. People with an underlying neurological disorder were not disproportionately represented in the DEET Registry. Data showed no clear relationship between case severity and DEET concentration or concurrent use of common medicines.Recognizing the extensive use of DEET in the US and considering the information about the more serious adverse events described in the Registry, the risk of serious neurological events following the use of DEET repellents is quite low.