Insect Sting Allergy

What is an allergic reaction to an insect sting?

Allergic reactions due to a hypersensitivity to stinging insect venom may happen after a sting from a:

  • Honeybee
  • Wasp
  • Yellow Jacket
  • Hornet
  • Fire Ant

Most people are not allergic to insect stings, and often mistake a normal or local reaction for an allergic reaction. The severity of an insect sting reaction varies. 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 spreading up to the calf muscle. Depending upon the extent and nature of the swelling, allergy evaluation and treatment guidelines are recommended.
  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. People who have experienced a systemic allergic reaction to an insect sting have roughly a 60% chance of a similar or worse reaction to a subsequent sting by the same insect.

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

Most people will experience one or more of the above symptoms from a sting. These symptoms are not alarming and can be treated with conservative measures.

Can severe allergic reactions to insect stings be prevented with venom allergy shots?

If you have had a severe allergic reaction to one of the stinging insects, it is important to seek information from an allergist. Based on your history and diagnostic test results (skin testing and blood tests that determine the degree of hypersensitivity), the allergist will determine if you are a candidate for venom immunotherapy treatment. Although stinging insect allergy can be a serious, and at times a life-threatening problem, the risk and fear of allergic reactions can be reduced or eliminated with venom immunotherapy.

Venom immunotherapy is a highly effective preventative vaccination program which can prevent future allergic reactions to insect stings by building up an immunity to the venom. Gradually increasing doses of specific insect venom are administered over a three to five year period, stimulating the patient's own immune system to protect against, and reduce, the risk of a reaction. The venom shots are administered twice per week at first. Once the maintenance, or maximum, dose is reached, the interval between shots is slowly increased to a monthly schedule until therapy is stopped. After only a few months of therapy, the threat of a severe reaction to a sting is greatly reduced and patients can return to leading normal lives without the constant threat of a severe reaction.

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?

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 systemic (anaphylactic) allergic 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 Tylenol or Ibuprofen.
  • If the area of redness is getting larger and feels warm to the touch, you may have a skin infection called cellulitis. This requires immediate medical attention.
  • An allergic reaction is treated with epinephrine (adrenaline), either self-injected or administered by a doctor. Usually this injection will stop the development of more severe allergic reactions. 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 an Epi-pen Twin Pak (2 self-injectable units) 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 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 an Epi-Pen Twin Pak (2 units)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. Other medications to have available may include Benadryl and an oral steroid preparation. The allergist will devise a written treatment plan with you, teach you how to use an Epi-Pen, and review general treatment guidelines.

How can I prevent an allergic reaction?

Allergic reactions to insect stings can be prevented with venom immunotherapy (VIT). 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 (immune) to a future allergic reaction. VIT is highly recommended in all individuals who have experienced an anaphylactic reaction to an insect sting. The allergist will discuss the treatment process and make specific recommendations based upon the results of testing.

Let's say I am not sure which insect caused the sting reaction.

As part of your evaluation following an acute allergic reaction to an insect sting, the allergist will perform a series of skin tests to determine which insect venoms (honey bee, yellow jacket, hornet, wasp, fire ant) could potentially result in systemic symptoms. If you are a candidate for venom immunotherapy, the treatment mix will include all of the venoms you are sensitive to.

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.