Immunotherapy for allergies to insect stings

Treatment Overview

Immunotherapy is a series of allergy shots given to reduce your sensitivity to allergens that cause an allergic reaction. Small doses of allergens are injected under the skin. Over time, allergy shots can decrease the severity of your reaction to allergens. To treat allergies to insect stings, very small amounts of the venom of the insect or insects are used. The treatment also is sometimes called venom immunotherapy (VIT).

Immunotherapy is available to treat allergies to stings from:

• Honeybees.
• Yellow jackets.
• Hornets.
• Paper wasps.
• Fire ants.

A solution of dilute saline containing a very small amount of the insect venom is injected under the skin. At first, you get one or more shots about once a week. The amount of allergen injected is slightly increased each time, unless you have a reaction to the shot.

After about 4 to 6 months of weekly shots, you are usually getting an optimal amount of allergen in the shot—this is called the maintenance dose. After you reach maintenance level, you get the same dose in shots every 4 weeks for another 4 to 6 months.

After the first year of shots, you will have maintenance shots every 6 to 8 weeks over the next 3 to 5 years.¹

Depending on your situation, your doctor may recommend rush immunotherapy. Several shots are given over a period of days to weeks. This type of treatment can provide faster protection in the short term. But you will still need to have regular shots over the long term.

What To Expect After Treatment

Allergy shots are usually given in a doctor's office. It is normal to remain in the doctor's office for a short time after getting an allergy shot to be watched for possible serious reactions to the injected insect venom.

Redness and warmth at the shot site are common but go away after a short time.

Why It Is Done

Immunotherapy can prevent life-threatening reactions and also reduce anxiety associated with insect stings.

An allergic reaction that spreads far from the sting or that affects the entire body is called a systemic reaction. Systemic reactions are not common but can be life-threatening. Allergy shots are usually recommended if an adult or child has had a severe systemic reaction, especially anaphylaxis. Immunotherapy reduces the risk of another severe systemic reaction.

How Well It Works

Immunotherapy for insect stings significantly reduces your chances of having another severe systemic allergic reaction from 60% to less than 3%.¹

It is not clear exactly how effective the protection against future stings is after the treatment has ended. In about 80% to 90% of cases, you will still be protected against systemic reactions even if tests show some remaining immune sensitivity.¹

Risks

Allergy shots are safe if the shots are given correctly. The most common side effects are redness and warmth at the shot site. Some people may experience large local reactions that include itching, hives, or swelling of the skin near where you had the shot. More serious but less common side effects include systemic symptoms such as hives, itching, or difficulty breathing.

In rare cases, a person may have a severe allergic reaction (anaphylaxis) to the shots. Because of this possibility, the shots are given in a doctor's office or other setting where emergency care can be provided if needed.

Allergy shots should not be used if you:

• Have certain heart conditions, especially unstable angina or a recent heart attack.
• Are not expected to live for at least 5 more years.
• Are not able to communicate about reactions to shots. Most doctors do not give allergy shots to children younger than age 5.
• Have an impaired immune system due to a chronic disease (such as AIDS). Talk to your doctor first about whether allergy shots would be safe for you.
• Are taking beta-blockers, such as propranolol (Inderal, for example) or timolol maleate (Timoptic or Blocadren, for example), which are often used to treat heart conditions, glaucoma, migraine headaches, and high blood pressure.
• Are taking ACE inhibitors, such as captopril (Capoten, for example) or lisinopril (Prinivil, Zestril, or Zestoretic, for example), which are often prescribed for high blood pressure and a variety of heart conditions. Talk to your doctor first about the potential risks of immunotherapy.

What To Think About

People with multiple insect venom allergies may still be at risk for a severe systemic reaction if they are receiving allergy shots for only one type of insect venom.

Immunotherapy is generally not needed for adults or children who have only a large local reaction to a sting. But anyone who experiences increasingly severe large local reactions with each new sting may want to consider immunotherapy.

Allergy shots take 3 to 5 years to complete and are expensive. You have protection from insect sting allergies after you have had the series of initial shots and after you start your maintenance dose. This may take about 1 to 2 months for standard immunotherapy but only 1 to 8 days with rush immunotherapy.

For more information about what to consider if you are thinking about having immunotherapy, see:

Should I have allergy shots (immunotherapy) for allergies to insect stings?

Complete the special treatment information form (PDF)(What is a PDF document?) to help you understand this treatment.

Author:	Caroline Rea, RN, BS, MS	Last Updated: January 22, 2008
Medical Review:	William M. Green, MD - Emergency Medicine Harold S. Nelson, MD - Allergy and Immunology
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