A UK review in the April Drug and Therapeutics Bulletin (DTB) says there is scant evidence that over-the-counter remedies for simple insect bites work, suggesting that in most cases, no treatment at all is enough.
The DTB concludes:
“There is little evidence for the efficacy of treatments for simple insect bites. The symptoms are often self limiting and in many cases, no treatment may be needed.”
Most of the insect bites inflicted on people in the UK are from midges, mosquitoes, flies, fleas and bedbugs, looking for a blood meal.
When they bite, these insects inject saliva into the wound, causing a reaction, such as itching and inflammation.
Some bites can result in infection, an eczema flare-up, or anaphylactic shock. Clearly these reactions warrant appropriate treatment, says DTB, but that is not what their review is about: their beef is with the over-the-counter medications used to treat the vast majority of milder reactions: the itching, swelling, pain, and secondary problems that come from scratching.
For instance, steroid creams have been shown to help people with eczema, but there is no evidence they are effective for the sort of itching and inflammation you get from an insect bite, says DTB.
Also, there is no evidence that steroid tablets work for severe localized and systemic reactions to insect bites, despite the fact they are recommended for this.
DTB urges people to use steroid creams very sparingly and never apply them to the face or broken skin.
Another remedy they raise doubts about is the widely recommended antihistamine tablet, used for pacifying the itching that accompanies insect bites. But according to DTB, there is little evidence to support this either.
DTB says they could find no hard evidence on the effectiveness of Crotramiton against itching. They cite a note in the British National Formulary, the UK expert’s drug bible, that says the drug is of “uncertain value”.
There is little evidence that antiseptics and astringents relieve itching or burning, although there is some evidence that dilute ammonium solution (counter-irritant) helps, says DTB.
As for creams that contain painkillers or anaesthetics like lidocaine, benzocaine, sometimes with antihistamines and antiseptics, DTB says they are “marginally effective and occasionally cause sensitisation”.
DTB suggests that applying a cloth soaked in cold water to the wound is often the most effective way to treat a simple insect bite.
The review does not include treatments for bites from ticks, mites and lice.
DTB is published by BMJ Publishing Group Ltd. It is not a peer-reviewed journal; its articles are produced by editors in consultation with experts.
Written by Catharine Paddock PhD