Once Bitten, Twice Shy

Allergy shots can reduce the risk of severe allergic reactions to insect stings

(RxWiki News) Summer is a wonderful time to enjoy the great outdoors. But a hot and dry climate also means having to endure those pesky bug bites and stings.

Most people are not allergic to insect stings but, for some, these stings can lead to severe allergic reactions including swelling, difficulty breathing, skin rashes and dizziness. In some cases, these reactions can even be fatal.

Allergy shots that can build resistance to insect stings may be an effective way to reduce severe allergic reactions, according to a new study.

"Take proper precautions to avoid bug bites and stings"

This review was conducted by David Golden, MD, Associate Professor of Medicine at Johns Hopkins Bayview Medical Center and American College of Allergy, Asthma & Immunology fellow, and colleagues.

The aim of this study was to examine the effect of allergy shots, called venom immunotherapy, on allergic reactions caused by insect stings.

Venom immunotherapy injections are allergy shots that are given to prevent future allergic reactions to insect stings.

These allergy shots inject small doses of insect venom with gradually increasing doses to help the immune system become resistant to the insect venom. Typically, people get protection from future allergies within two to three months of treatment.

For this study, the researchers looked at several previous studies related to insect stings. In particular, they examined data from people who had allergic reactions to insect stings in the past.

According to the researchers, if stung again, an adult has a 70 percent chance of having a second allergic reaction, even 10 to 20 years after the first insect sting. Among children who are stung by insects, the chance of having a second allergic reaction in the next decade or two is close to 30 percent.

The researchers also examined reaction rates in those who got allergy shots after their first reaction.

Allergy shots are not completely foolproof in preventing an allergic reaction, according to this study. But among those who get these shots, only 5 to 10 percent have another allergic reaction. Plus, this reaction is usually mild. The chance of having a severe allergic reaction is just 2 percent.

"While it does not always cure insect sting allergy, venom immunotherapy, a form of allergy shots, can almost always prevent severe reactions to stings," said Dr. Golden in a press statement. "It usually provides long-lasting immunity even after the treatment is stopped.

"Allergy sufferers who have had an allergic reaction to an insect sting should be under the care of a board-certified allergist," said Dr. Golden. "For those with severe reactions, prescribed emergency epinephrine should always be carried. Sufferers should also talk with their allergist to see if venom immunotherapy is right for them. It's not always a cure, but it is close."

Epinephrine (brand name: Epipen) is prescribed to people who are at high risk of severe allergic reactions. People can inject themselves with a dose of epinephrine after an insect sting to combat severe symptoms.

"An epinephrine injector will usually stop a severe reaction once it starts, but if the person is on venom immunotherapy, they will not even need an epinephrine device because they won't even have a reaction when they get stung. So our message to the public is to not ignore a severe sting reaction, and to see an allergist for proper testing and treatment," Dr. Golden told dailyRx.

The researchers noted that since the return of the allergic reaction is possible even after getting allergy shots, people who have had allergic reactions to insect stings in the past have to be monitored regularly by their allergist.

In a press release, the American College of Allergy, Asthma & Immunology (ACAAI) also provided advice on how to avoid insect bites and stings.

The ACAAI recommends covering up with pants and long-sleeved shirts while outdoors and avoiding walking barefoot in the grass. Insects are attracted to sweet drinks and foods, so staying cautious when eating or drinking outdoors is important. The ACAAI also suggests avoiding sweet-smelling perfumes and brightly-colored clothing with floral patterns that can also be bug magnets.

The results of this study were published August 1 in the Annals of Allergy, Asthma & Immunology, the official journal of the American College of Allergy, Asthma, & Immunology.

This study did not receive any external commercial support. The lead author, Dr. Golden, disclosed prior speaking engagements at Genentech and Sanofi. He also reported receiving grants from Siemens and Genentech. No conflicts of interest were disclosed by the other authors.

Review Date: 
August 1, 2013