There is little evidence that over-the-counter cures for insect bites work, according to new research today.
The journal Drug and Therapeutics Bulletin assessed the medical evidence for the efficacy of treatments for bites by midges, mosquitoes, flies, fleas and bedbugs.
Bites could cause infections, eczema flare ups and, in severe cases, anaphylactic shock – all requiring medical treatment - but in most cases the reaction was mild for which there was little or no proof that chemists’ remedies worked, the study found.
In most cases individuals would be better off letting the itching, pain and swelling ease naturally, it concluded.
The study looked at the incidence and treatment of common insect bites in the UK, but excluded lacerations by ticks, mites and lice.
Although on average each week GPs saw only five cases of insect bites per 100,000 patients, the problem was greater because people often consulted a pharmacist, used over-the-counter cures or did not seek treatment, the study said.
Bites by mosquitoes, bedbugs and fleas are generally mild because they have “piercing mouthparts” that slice open the skin, and inject saliva containing anti-coagulant to keep the blood flowing, though itching and swelling follow. By contrast, horseflies, gnats and midges rip apart the skin more roughly and cause more painful wounds – which can cause dizziness, weakness and wheezing.
Although antihistamine tablets are widely recommended to quell the itching associated with insect bites, the study found there was not much evidence to support their use.
There was also no actual evidence to support the use of steroid creams and tablets recommended for itching and inflammation, except for people with eczema.
Creams containing painkillers or anaesthetics, such as lidocaine, benzocaine, or combined with antihistamines and antiseptics, were only “marginally effective.” There was no hard evidence for the use of the anti-itch preparation Crotramiton, and the drugs bible, the British National Formulary, noted it was “of uncertain value.”
The study said that while was some evidence to suggest that dilute ammonium solution (counter-irritant) might help relieve itching and/or burning, there was little evidence for antiseptics or astringents.
The research concluded: “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.”