Venom immunotherapy: Defusing the danger of winged insect stings

Bzzzzzzz ... uh-oh! If you're allergic to the venom of bees or wasps, hearing them buzzing nearby can be scary - and maybe even make you panic. After all, a sting could, at worst, cause a severe, life-threatening overreaction of your immune system.

Called anaphylaxis or anaphylactic shock, its symptoms include difficulty breathing, a rapid heart rate, sudden drop in blood pressure and loss of consciousness.

Many people aware of their allergy arm themselves in summer against winged insects by keeping an emergency kit at hand that contains an epinephrine (adrenaline) auto-injector. Injected into the thigh, epinephrine reduces the body's allergic response.

Being thus forearmed may do little to allay their fear though. But as the German Dermatological Society (DDG) points out, there's a way to treat the cause of the problem and not merely the symptoms: venom immunotherapy.

How does it work? An allergist regularly injects small doses of the venom you're allergic to under your skin, gradually increasing the amount, in order to desensitize your immune system to the allergen so that it no longer overreacts.

The therapy takes three to five years to complete, the DDG says, and it's important to stick to the schedule. Injections are given once a week at first, and then every four to eight weeks. Besides allergists, doctors qualified to administer them include dermatologists, ENT specialists, GPs and paediatricians with additional training in allergology

Undergoing the full course of therapy is highly effective. The DDG estimates that it prevents 90% of anaphylactic shocks caused by insect venom.

Venom immunotherapy isn't for everyone who has an allergic reaction to insect bites or stings. Medical guidelines recommend it for those with at least stage two anaphylaxis ("moderate" - there are four stages in all). In addition to stage one symptoms - skin rash or redness, itching and hives - it's characterized by nausea, circulatory problems, difficulty swallowing and/or breathing.

Sometimes, however, the therapy is a good idea in stage one cases too, namely for people at a higher occupational risk of insect bites or stings since they work, for instance, in a bakery or garden centre.

According to the DDG, swelling of up to 10 centimetres around a bee or wasp sting is normal. But if it's much larger or lasts longer than 24 hours, you should see a doctor.