What is an allergic reaction to an insect sting?

Allergic reactions occurring due to a hypersensitivity reaction to stinging insect venom may occur after a sting from a :

  • Bee
  • Wasp
  • Yellow jacket
  • Hornet
  • Fire ant

Most people are not allergic to insect stings and may mistake a normal or local reaction for an allergic reaction. By knowing the difference, the patient can prevent unnecessary worry and visits to the doctor’s office or hospital emergency room.

The severity of an insect sting reaction varies from person to person. There are three types of reactions:

  1. A normal reaction may result in pain, swelling, and redness around the sting site.
  2. A large local reaction may result in swelling that extends beyond the sting site. For example, a person stung on the ankle may have swelling of the entire leg. While it often looks alarming, generally, it resolves on its own and does not progress to a systematic reaction.
  3. The most serious reaction to an insect sting is an allergic one (described below). This condition requires immediate medical attention.

What are the symptoms?

Symptoms of a severe allergic reaction or anaphylactic reaction may include one or more of the following:

  • Difficulty breathing
  • Hives which appear as a red, itchy rash that spreads to areas other than the immediate area stung
  • Swelling of the face, throat or mouth tissue
  • Wheezing or difficulty swallowing
  • Restlessness and anxiety
  • Rapid pulse
  • Dizziness or a loss of consciousness due to a sharp drop in blood pressure

Although severe allergic reactions are not that common, they can lead to shock, cardiac arrest and unconsciousness in 10 minutes or less. This type of reaction can occur within minutes after the sting and may be life-threatening or even fatal. Get emergency treatment as soon as possible.

A mild allergic reaction to an insect sting may cause one or more of the following symptoms at the site of the sting:

  • Pain
  • Redness
  • Pimple-like spots
  • Mild to moderate swelling
  • Warmth at the sting site
  • Itching

People who have experienced an allergic reaction to an insect sting roughly have a 60% chance of a similar or worse reaction if they are stung again.

How common are sting allergies?

About two million Americans are allergic to the venom of stinging insects. Many of these individuals are at risk for life-threatening allergic reactions. Approximately 50 deaths each year in the US are attributed to allergic reactions to insect stings.

How are normal or localized reactions treated?

  • First, if stung on the hand, remove any rings on your fingers immediately. A stinging insect may leave a sac of venom and a stinger in the victim's skin. If the sac is still in the skin, gently scrape it out with a fingernail or a stiff-edged object like a credit card. Do not pull on the stinger as this will cause the release of more venom into the skin.
  • Wash the stung area with soap and water then apply an antiseptic.
  • Apply a soothing ointment, like a hydrocortisone cream or calamine lotion and cover the area with a dry, sterile bandage.
  • If swelling is a problem, apply an ice pack or cold compress to the area.
  • Take an oral anti-histamine, like Benadryl, to reduce itching, swelling and hives. However, this medication should not be given to children under 3 years of age or to a pregnant woman without prior approval from a doctor.
  • To relieve pain, take aspirin or an aspirin-substitute. However, do not give a child or teenager aspirin. (Aspirin use in these age groups has been associated with a rare but serious liver and brain disorder called Reye's syndrome).

In general, pregnant women should consult their doctor before taking any over-the-counter medication. Also, it is always recommended that you read the warning label on any medication prior to taking it. Parents of children and people with medical conditions are advised to read product labels carefully and consult a pharmacist if they have questions about use.

How are allergic reactions treated?

An allergic reaction is treated with epinephrine (adrenaline), either self-injected or administered by a doctor. Usually this injection will stop the development of severe allergic reaction. In some cases, intravenous fluids, oxygen and other treatments are also necessary. Once stabilized, these patients are sometimes required to stay overnight at the hospital under close observation. People who have had previous allergic reactions and rely on the protection of epinephrine must remember to carry it with them wherever they go. Also, because one dose may not be enough to reverse the reaction, immediate medical attention following an insect sting is recommended.

How can I avoid being stung?

You can lessen your chances of an insect sting by taking certain precautionary measures:

  • Learn to recognize insect nests and avoid them. Yellow jackets nest in the ground in dirt mounds or old logs and in walls. Honeybees nest in beehives. Hornets and wasps nest in bushes, trees and on buildings.
  • Wear shoes and socks when outdoors.
  • Wear long-sleeved shirts, long pants, socks and shoes, when in country or woodsy areas.
  • Limit wearing perfumes or brightly colored clothing, they tend to attract insects.
  • People who have severe allergies should never be alone when hiking, boating, swimming, golfing or otherwise involved outdoors, as they may need prompt medical treatment if stung.
  • Use insect screens on windows and doors at home; use insect repellents; spray bedrooms with aerosols containing insecticide before going to bed.
  • Spray garbage cans regularly with insecticide and keep the cans covered.
  • Avoid or remove insect-attracting plants and vines growing in and around the house.

Every allergic person should always wear a medic alert bracelet and keep a self-care kit like Ana-Kit or Epi-Pen on hand for emergency use in the case of severe symptoms. You will need a prescription from your doctor to obtain one of these kits. For more information on where to get a medic alert bracelet, you can call 1-800-ID-ALERT.

How can I prevent an allergic reaction?

Allergic reactions to insect stings can be prevented with venom immunotherapy. The treatment is at least 97% effective in preventing future occurrences. It involves administering gradually increasing doses of venom to stimulate the patient's own immune system to become resistant to a future allergic reaction.

How can I find out more about venom immunotherapy?

If you've had an allergic reaction, it's important to seek information from an allergist, a doctor who specializes in the diagnosis and treatment of allergic disease. Based on your history and diagnostic tests, the allergist will determine if you are a candidate for immunotherapy treatment. Although stinging insect allergy is a serious problem, the risk and fear of allergic reactions can be reduced or eliminated with immunotherapy.

What are Epinephrine sting kits?

Epinephrine self-administration kits are important for a patient to use before he or she can get to a physician for treatment. However, epinephrine kits should not be used as a substitute for an allergy evaluation and physician intervention. Epinephrine alone is not always enough to reverse serious allergic sting reactions and may cause serious side effects in some patients with heart conditions or patients who are taking certain medications. Before using, be sure to check with your physician to prevent drug interactions.

Reviewed by a Cleveland Clinic medical professional.

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