Allergies to Insect Stings

Topic Overview

What are allergies to insect stings?

When you are stung by an insect, poisons and other toxins enter your skin. It is normal to have some swelling, redness, pain, and itching around the sting. But you may have an allergic reaction if your immune system reacts strongly to allergens in the sting.

You probably will not have a severe allergic reaction the first time you are stung. But even if your first reaction to a sting is mild, allergic reactions can get worse with each sting. Your next reaction may be more severe or even deadly.

What causes an allergic reaction to insect stings?

An allergic reaction occurs when your immune system reacts strongly to the allergens in the sting.

A few types of stinging insects cause most allergic reactions. They are:

  • Bees.
  • Wasps.
  • Hornets.
  • Yellow jackets.
  • Fire ants.

What are the symptoms?

Symptoms of an allergic reaction can range from mild to severe. Mild allergic reactions cause:

  • Redness and swelling around the sting.
  • Mild tenderness and itching around the sting.

A more serious allergic reaction can spread to your whole body. This kind of reaction can cause:

  • Itching anywhere on your body.
  • Hives .
  • Swelling of your tongue, throat, or other body parts.

A deadly allergic reaction, called anaphylaxis (say “ann-uh-fuh-LAK-suss”), can cause:

  • Confusion.
  • Trouble breathing.
  • Shock.
  • Death, in some cases.

How are allergies to insect stings diagnosed?

Your doctor may do a physical exam and ask you questions about your symptoms and past health. He or she also may want you to have allergy tests after you get better from the allergic reaction. These tests will help you find out which types of insect stings you are most allergic to.

How are they treated?

Treatment for insect sting allergies depends on how bad your reaction is. Most of the time, you can treat mild allergic reactions with home care. Try cold packs and medicines for pain, swelling, and itching. Most people don't need epinephrine or allergy shots for these mild allergic reactions.

A severe reaction (anaphylaxis) can be deadly and needs emergency care.

If you have severe reactions, you should carry an allergy kit. It includes antihistamine pills and an epinephrine shot, such as an EpiPen. You may also want to try allergy shots, called immunotherapy, to help prevent worse allergic reactions in the future.

How can you prevent insect stings?

To reduce your chances of being stung:

  • Stay away from places where insects nest.
  • Wear shoes, long sleeves, and long pants when you are outdoors.
  • Don't wear perfume or scented lotions.

Frequently Asked Questions

Learning about allergies to insect stings:

Being diagnosed:

Getting treatment:

Ongoing concerns:

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Symptoms

Symptoms of an allergic reaction to insect stings vary from mild to life-threatening. The severity of your allergic reaction depends on your sensitivity to the allergens in the venom—not necessarily on the number of stings or how often you have been stung in the past.

Normal reaction to insect stings

It is normal to have some immediate swelling, redness, pain, and itching at the site of an insect sting—toxins from the insect's venom enter the skin when you are stung. Normal symptoms from insect stings may last from a few hours to a few days, don't spread beyond the area of the bite, and include:

  • Pain.
  • Redness.
  • Swelling.
  • Itching.

A normal reaction to fire ant stings is slightly different. Fire ants sting numerous times in a cluster or ring, usually on a person's feet and legs because these are closest to the ground. The stings cause pain, redness, itching, and swelling at the site of the stings. Also, within several hours of being stung, small clear blisters appear and then fill with fluid within 24 hours.

Large local allergic reactions

A large local reaction is when redness and swelling from an allergic reaction spread outward from the site of the sting. The reaction may affect only the area around the sting itself (such as your hand or forearm). Or it may involve an entire limb or a broad area of the body. A large local reaction does not affect the entire body. It often will spread to cross the major joints on either side of the sting, such as the elbow and shoulder if you are stung on the upper arm. You may also experience a low fever, nausea, or fatigue. Symptoms usually occur 12 to 24 hours after you are stung and go away in 5 to 10 days.1

People who have large local reactions to stings sometimes have a more severe local reaction each time they are stung. But for both children and adults, the risk of having a systemic (whole-body) reaction is relatively low, from 1% to 3%.1

Systemic reactions

Symptoms of a systemic allergic reaction develop in a different location than where you were stung and range from moderate to life-threatening. A severe systemic reaction is called anaphylaxis and requires immediate medical treatment.

Common systemic allergic reaction symptoms include:

  • Red, warm skin (flushing).
  • Itching.
  • Hives .
  • Swelling in the deep layers of the skin (angioedema) or mucous membranes (such as the nose and throat). The swelling may occur in the lips, tongue, mouth, throat, ears, eyelids, palms, or soles of the feet.

Serious, life-threatening systemic allergic reaction (anaphylaxis) symptoms can include the symptoms above and:

  • Swelling and tightness in the throat or chest.
  • Wheezing, coughing, and constriction or swelling in the throat that makes it difficult to breathe.
  • Dizziness.
  • Confusion, agitation, lightheadedness.
  • Abdominal cramps, nausea, vomiting, or diarrhea.
  • Abnormal heartbeat (arrhythmia) .
  • A drop in blood pressure.
  • Shock that can lead to death.

Systemic reactions usually develop within 15 to 30 minutes or, sometimes, up to an hour after being stung. In some cases, anaphylaxis may continue or recur for 6 to 24 hours after a person is stung, and continued intensive treatment may be needed.1

If you had a previous systemic allergic reaction to a sting, you are at great risk of having a similar reaction if you are stung again.

Every systemic reaction to an insect sting should be considered a medical emergency. If you have a systemic allergic reaction, you should be observed in a clinic or emergency room afterwards to make sure you do not develop severe symptoms. If you have symptoms of a severe allergic reaction, seek immediate medical care by calling 911 or other emergency services.

You may also have another reaction to an insect sting that is not an allergic reaction (such as a toxic reaction or serum sickness).

Exams and Tests

Your doctor will diagnose an allergic reaction to insect stings by performing a physical exam and taking your medical history.

Your doctor may refer you to a specialist, such as an allergist (immunologist), who will perform allergy tests, such as skin tests or blood tests, to identify your allergies. The skin tests may involve many skin pricks to see what kinds of insect stings you are allergic to.

It is possible that you will not show any sensitivity to allergens in allergy tests even after you have had an allergic reaction to an insect sting.2 Your doctor may recommend that you repeat these tests in 3 months.

Treatment Overview

Key treatment points

  • For normal reactions to insect stings, medical treatment is usually not needed. An ice pack or cold compress may reduce swelling and pain, along with taking a nonprescription pain reliever, such as acetaminophen.
  • If you have a large local reaction that spreads around the sting or affects an entire limb, taking an antihistamine can reduce your overall symptoms. Don't give antihistamines to your child unless you've checked with the doctor first.
  • Systemic allergic reactions involve your whole body and are considered a medical emergency. If you have had a severe systemic reaction to an insect sting in the past, carry an allergy kit with you so that, when stung, you can immediately treat yourself with the antihistamine tablet and epinephrine injection from the kit. Always seek emergency care after an epinephrine injection—your symptoms could reappear or become worse for several hours after the first epinephrine injection.
  • If your systemic reaction gets worse, you may develop anaphylaxis, which is a life-threatening response to the insect venom. Emergency medical attention is needed. Call 911 or seek immediate treatment in a hospital emergency room. Medicines will be given to reduce swelling, open your airway to help you breathe, and stabilize your blood pressure.

Allergies to insect stings are treated by avoiding the insects that cause the allergy, treating mild cases with medicines such as antihistamines, and understanding how and when to use an allergy kit for serious reactions.

Special care must be taken with children who have insect sting allergies. A child with a severe allergy may have life-threatening anaphylactic reactions to even tiny amounts of venom from the insect. Your child should always wear a medical alert bracelet and carry an allergy kit. Children at risk for severe allergic reactions should keep allergy kits at school or day care and at home. Make sure that all caregivers—such as school administrators, teachers, friends, and coaches—know about the insect sting allergy, where the allergy kit is kept, and how and when to give the epinephrine injection. Also, make sure they have a plan to transport your child to the hospital. Older, mature children should be taught to give self-injections.

Click here to view an Actionset. Allergies: Giving yourself an epinephrine shot

Immediate treatment for an allergic reaction to an insect sting depends on the type and severity of your symptoms.

Normal reaction to insect stings

For the normal reaction that most people have to a sting, medical treatment is usually not needed. An ice pack or a cold compress and nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen may relieve some of the swelling and pain. Nonprescription pain relievers such as acetaminophen (for example, Tylenol) may reduce pain, and oral antihistamines such as diphenhydramine (for example, Benadryl) can reduce itching. Don't give antihistamines to your child unless you've checked with the doctor first. And do not give aspirin to anyone younger than 20 because of the risk of Reye syndrome.

Large localized allergic reaction

Treatment for large local allergic reactions usually consists of:

  • Cold compresses or ice packs, to reduce swelling and local pain.
  • Elevating the limb (if this is where the sting occurred), to reduce swelling.
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) , to reduce swelling and pain.
  • Nonprescription pain relievers such as acetaminophen, to reduce pain. Follow all instructions on the label. If you give medicine to your baby, follow your doctor’s advice about what amount to give.
  • Antihistamines, which can reduce overall symptoms. Don't give antihistamines to your child unless you've checked with the doctor first.
  • Anesthetic creams or ointments, which may reduce pain and itching.
  • Corticosteroids (such as prednisone), which can reduce swelling and pain. (The use of corticosteroids to treat local allergic reactions is controversial.)

Systemic allergic reactions

Systemic (whole-body) allergic reactions to a sting are considered a medical emergency. Immediate treatment is needed and may include:

Click here to view an Actionset. Allergies: Giving yourself an epinephrine shot
Click here to view an Actionset. Allergies in children: Giving an epinephrine shot to a child

Treatment for anaphylaxis—the most severe systemic allergic reaction, one that can be life-threatening—is designed to keep your airway open and relieve other breathing or heart problems that can occur, especially if there are signs of shock. In addition to epinephrine and an antihistamine, treatment for anaphylaxis may include:

If anaphylaxis is prolonged, medicines to stabilize blood pressure and other measures to help with breathing—such as oxygen, intubation, and possibly a ventilator—may be needed.

If you had anaphylaxis, you will normally need to stay in the hospital for 8 to 12 hours before being released. Symptoms of anaphylaxis can recur after several hours, so you may need additional medicine or treatment.

Long-term treatment

If testing and exams confirm that you are allergic to insect stings, long-term treatment usually includes:

  • Avoiding or preventing stinging insects. You can reduce your chances of being stung by avoiding areas where insects nest; wearing shoes, long sleeves, and long pants when you are outdoors; and not wearing perfume or scented lotions.
  • Carrying an allergy kit. The kit contains emergency medicine, including antihistamine tablets and an epinephrine injection that you can immediately self-administer if you are stung. Talk with your doctor about how to store your kit and when and how to give yourself the injection.
  • Wearing a medical alert bracelet or medallion. At most pharmacies or on the Internet, you can purchase a medical alert bracelet or other jewelry that lists your insect sting allergies. Medical alert jewelry quickly alerts emergency response workers to your allergy. This helps them give immediate and appropriate treatment.
Click here to view an Actionset. Allergies: Giving yourself an epinephrine shot
Click here to view an Actionset. Allergies in children: Giving an epinephrine shot to a child

If you have a history of systemic allergic reactions, you may consider treatment with a series of shots (immunotherapy) to reduce your sensitivity to the stinging insect's venom and lower your risk of a severe reaction. Immunotherapy is usually 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. Talk with your doctor or allergy specialist to see whether immunotherapy is appropriate for you.

Click here to view a Decision Point. Allergies: Should I take shots for insect sting allergies?

Home Treatment

Knowing which insect venom triggers your allergies and avoiding those insects is the best way to avoid allergic reactions to the stings. Unfortunately, it can be difficult to avoid insects, especially if you spend time outdoors.

Home treatment for allergic reactions to insect stings includes:

  • Avoiding or preventing exposure to stinging insects, such as not using scented lotions or perfume, not wearing brightly colored clothing, and not going barefoot when you are outdoors.
  • Learning what types of stinging insects you are allergic to, including how to identify them and where they live, so you can better avoid them.
  • Carrying an allergy kit containing emergency medicines you can use if you are stung. Make sure you keep the supplies fresh and know how and when to properly use them. You need to have an allergy kit with you at all times. Check your kit regularly and replace medicines that have passed their expiration dates. Allergy kits with doses appropriate for children are available. Children at risk for severe allergic reactions should keep kits at school or day care and at home.
  • Wearing a medical alert bracelet or medallion that lists your insect sting allergies, to alert emergency response workers if you have a severe allergic reaction. Medical alert jewelry can be ordered through most pharmacies or on the Internet.

Educate yourself and others

  • If you or your child is allergic to insect stings, know what those particular insects look like and where they live.
  • Make sure that all caregivers—such as school administrators, teachers, friends, and coaches—and coworkers know about the insect sting allergy, know what the symptoms look like during an allergic reaction, know where the allergy kit is kept and how to give the epinephrine injection, and have a plan to transport you or your child to the hospital.
  • Teach older, mature children how to give self-injections.

What to do if you are stung

  • Move away from the stinging insect and leave the area immediately—there may be a nest nearby.
  • Remain as calm and quiet as possible. Movement will increase the spread of venom in the bloodstream.
  • Remove the stinger from your skin immediately (see how to remove a stinger). It may be best to scrape or flick the stinger off your skin—squeezing or gripping the stinger to pull it out may inject more venom into your wound.
  • Lower your arm or leg (if you have been stung in a limb) to slow the spread of venom. If the limb later becomes swollen, you can try elevating the affected leg or arm.

For normal, local sting reactions and large local allergic reactions, try the following:

  • Use a cold compress or ice pack to reduce swelling. Elevate the affected part of the body to help reduce swelling.
  • Take a nonprescription pain reliever, such as aspirin, acetaminophen (for example, Tylenol), or ibuprofen (for example, Advil). Do not give aspirin to anyone younger than age 20, unless it is prescribed by a doctor, because of the risk of Reye syndrome.
  • Take an antihistamine to help reduce your symptoms. Read and follow the warnings on the label. And don't give antihistamines to your child unless you've checked with the doctor first.

Emergency care for a severe allergic reaction

Any systemic reaction (anaphylaxis) to an insect sting should be considered a medical emergency. If you have symptoms of a severe allergic reaction—such as difficulty breathing, dizziness, swelling of your tongue or throat, or abdominal cramps—call 911 or other emergency services immediately.

If your doctor has prescribed an allergy kit, use the kit if:

  • You have been taught how and when to use it.
  • Your symptoms are severe.
  • You have a kit immediately available.
  • You have had a severe reaction in the past from a sting from the same type of insect, and similar symptoms are developing.

Antihistamines can help reduce your symptoms. But antihistamines may not be strong enough for severe reactions. And they shouldn't be given to children unless the doctor has said it's okay. Even though it can be scary to give yourself an epinephrine shot, it may be the only way to stop a severe reaction.

Other Places To Get Help

Organizations

American Academy of Allergy, Asthma, and Immunology
555 East Wells Street
Suite 1100
Milwaukee, WI  53202-3823
Phone: 1-800-822-2762 (doctor referral information only)
(414) 272-6071
E-mail: info@aaaai.org (For general questions only. The AAAAI cannot answer individual questions relating to the diagnosis or treatment of allergies.)
Web Address: www.aaaai.org
 

The American Academy of Allergy, Asthma, and Immunology publishes an excellent series of pamphlets on allergies, asthma, and related information. It also provides physician referrals.


American College of Allergy, Asthma, and Immunology (ACAAI)
85 West Algonquin Road
Suite 550
Arlington Heights, IL  60005
Phone: 1-800-842-7777 (allergist referral service)
E-mail: mail@acaai.org
Web Address: www.acaai.org
 

The American College of Allergy, Asthma, and Immunology (ACAAI) provides allergy information for consumers, including a nationwide allergist referral service.


Asthma and Allergy Foundation of America (AAFA)
1233 20th Street NW
Suite 402
Washington, DC  20036
Phone: 1-800-7-ASTHMA (1-800-727-8462)
E-mail: info@aafa.org
Web Address: www.aafa.org
 

The Asthma and Allergy Foundation of America (AAFA) provides information and support for people who have allergies or asthma. The AAFA has local chapters and support groups. And its Web site has online resources, such as fact sheets, brochures, and newsletters, both free and for purchase.


KidsHealth for Parents, Children, and Teens
10140 Centurion Parkway North
Jacksonville, FL  32256
Phone: (904) 697-4100
Fax: (904) 697-4125
Web Address: www.kidshealth.org
 

This Web site is sponsored by the Nemours Foundation. It has a wide range of information about children's health, from allergies and diseases to normal growth and development (birth to adolescence). This Web site offers separate areas for kids, teens, and parents, each providing age-appropriate information that the child or parent can understand. You can sign up to get weekly e-mails about your area of interest.


References

Citations

  1. Golden DB (2009). Insect allergy. In NF Adkinson Jr et al., eds., Middleton's Allergy: Principles and Practice, 7th ed., vol. 2, pp. 1005–1017. Philadelphia: Mosby Elsevier.
  2. Golden DBK, et al. (2001). Insect sting allergy with negative venom skin test responses. Journal of Allergy and Clinical Immunology, 107(5): 897–901.

Other Works Consulted

  • Golden DBK (2007). Allergic reactions to hymenoptera. In DC Dale, DD Federman, eds., ACP Medicine, section 6, chap. 15. New York: WebMD.
  • House H (2006). Insect bites and stings. In MR Dambro, ed., Griffith's 5-Minute Clinical Consult, pp. 590–591. Philadelphia: Lippincott Williams and Wilkins.
  • Reisman RE (2007). Insect sting allergy. In P Lieberman, JA Anderson, eds., Allergic Diseases Diagnosis and Treatment, 3rd ed., vol. 1, pp. 71–81. Totowa, NJ: Humana Press.
  • Schwartz LB (2008). Systemic anaphylaxis, food allergy, and insect sting allergy. In L Goldman, D Ausiello, eds., Cecil Textbook of Medicine, 23rd ed., vol. 3, pp. 1947–1950. Philadelphia: Saunders Elsevier.
  • Bernstein IL, et al. (2008). Allergy diagnostic testing: An updated practice parameter. Annals of Allergy, Asthma, and Immunology, 100(3, Suppl 3): S1–S148.
  • Tankersley MS (2008). The stinging impact of the imported fire ant. Current Opinion in Allergy and Clinical Immunology, 8(4): 354–359.

Credits

Author Maria Essig
Editor Susan Van Houten, RN, BSN, MBA
Associate Editor Pat Truman, MATC
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Rohit K Katial, MD - Allergy and Immunology
Last Updated January 13, 2010

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