Do Allergy Shots Work For Insect Allergy?

Allergy shots for insect stings, also called venom immunotherapy, are the most effective known treatment to prevent allergic reactions to stings from honeybees, yellow jackets, hornets, paper wasps, and fire ants. Venom immunotherapy is offered to all patients who have had anaphylaxis following a sting and to adults who have had acute hives after a sting. In addition, patients with very large, aggressive local reactions who have positive skin tests may be considered as candidates, as shots have been recently shown to reduce the intensity of these reactions and a sting to the neck or face could have dire consequences.

If a person has no symptoms of allergic reactions to insect stings but is tested and found positive to a venom skin test, the chance of developing anaphylaxis with future stings is approximately 17%. In this circumstance, because a positive test now exists, venom allergy shots should be offered, given the small but significant chance of a severe allergic reaction in the future.

The therapy is started using extremely small amounts of venom from all of the insects that the patient is allergic to. Levels of these venoms are increased over time. After 4–6 months of weekly injections, most patients reach the highest tolerated dose of venom, which is referred to by allergists as the maintenance dose. Patients will usually receive the maintenance dose every 4 weeks for approximately 1 year, then every 6–8 weeks for 3–5 more years.

Patients who are at high risk for future stings (e.g., forest rangers, landscape designers) may benefit from receiving their initial immunotherapy more quickly, thus acquiring protection against future stings. This treatment program, which is called “rush immunotherapy,” consists of administering several shots each day, 2–3 days per week over a few weeks.Venom shots should always be given in a doctor’s office. It is normal to remain in the doctor’s office for at least 30 minutes after receiving an allergy injection in order to observe for any possible systemic reactionot Immunotherapy for insect stings significantly reduces your chances of having another severe systemic allergic reaction from 60% to less than 3%.

It is not clear exactly how effective the protection against future stings is after the treatment has ended. In about 80–90% of cases, patients will still be protected against systemic reactions even if allergy tests show some remaining allergy to the venom. Venom immunotherapy is safe if the shots are given correctly and the most common side effect is redness and warmth at the injection site. Some people may experience large, local reactions that include itching, hives, or swelling of the skin.

Less commonly, a shot  may lead to systemic symptoms such as hives, itching, or difficulty breathing. For this reason, venom immunotherapy should always be administered by a physician familiar with this type of therapy and who is prepared to treat a systemic reaction.