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Insect bites and stings - Management
Which insect repellent should I recommend?

  • Use insect repellents that contain DEET (diethyl-toluamide) as they are more effective than other insect repellents.
  • CKS recommends formulations that contain 50% DEET.
    • These have the longest duration of protection (up to 12 hours).
    • There is no evidence that any group (including pregnant women and small children) is at increased risk from using 50% DEET.
Clarification / Additional information
  • DEET applications can damage some plastic watch straps, watch 'glass', and plastic jewellery; these items should not be allowed to come into contact with DEET.
  • When both sunscreen and DEET are required, DEET should be applied after application of sunscreen.
  • DEET reduces the efficacy of sunblock, but sunscreens do not reduce the effectiveness of DEET.
Basis for recommendation
  • These recommendations are based on expert opinion from Guidelines for Malaria prevention published by the Health Protection Agency [Chiodini et al, 2007], and expert reviews from the medical literature.
  • Lower concentrations of DEET (diethyl-toluamide) have shorter durations of protection and require more frequent applications. The duration of protection for DEET is:
    • 1 to 3 hours for 20%.
    • Up to 6 hours for 30%.
    • Up to 12 hours for 50%.
    • There is no further increase in duration of protection beyond a concentration of 50%.
  • For malaria prevention concentrations of DEET below 20% are considered inappropriate in any circumstances [Chiodini et al, 2007].
  • There is no evidence that any group (including pregnant women and small children) is at risk from using 50% DEET.
  • Other commercially available products do not afford the same amount of protection as 50% DEET:
    • Lemon eucalyptus oil gives about the same amount of protection as afforded by 15% DEET.
    • Picaridin is reported to have repellent properties comparable to 20% DEET.
    • Citronella oil provides short-lived protection (20–30 minutes).
  • There is no evidence that garlic, thiamine (vitamin B1), bath oils, or tea tree oil are capable of repelling mosquitoes.

[Roberts and Reigart, 2004; CCDR, 2005; Chiodini et al, 2007]

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