Insect Sting Allergy and Its Management

Introduction

Every year thousands of people report of insect sting. Studies have shown that life-threatening allergic reactions usually occur in 0.4 to 0.8 % of children and 3 % of adults. Around 90 to 100 deaths are caused by insect sting anaphylaxis (life-threatening allergic reaction). Usually, bees, wasps, yellow jackets, hornets, or fire ants cause insect stings that may or may not be allergic. Most people are not allergic, but knowing the difference between normal and allergic reactions can help the person decide whether to visit a doctor or not.

What Is an Allergic Reaction to an Insect Sting?

Usually, insect stings cause minor reactions, which include redness, swelling, or itching at or around the site of the sting. This usually subsides with time. But for a few people, being stung by an insect may result in severe reactions or even death. In the United States, almost 90 to 100 deaths occur due to insect stings every year.

What Is Meant by an Allergic Reaction?

The response of the immune system to some foreign substance with cells helps to detect the particular invader. When there is a response reaction of the immune system, antibodies are produced. These antibodies help the immune system to find foreign substances and help get rid of them. There are many types of antibodies with specific roles, one type of antibody is immunoglobulin E (IgE), which is related to the development of the allergic reaction.

When a person experiences any allergic reaction due to an insect sting then the immune system produces IgE antibodies, which target the insect's venom. If this reaction occurs again the action of IgE antibodies will be more rapid and vigorous. IgE response results in the release of histamine and other chemicals that are responsible for the cause of allergy symptoms.

Which Bite of Insect Results in an Allergic Reaction?

Commonly three families of insects cause most insect sting allergy, these are:

• Vespids (Vespidae):

These include yellow jackets, hornets, and wasps.

• Bees (Apidae):

These include honey bees, and rarely bumblebees and sweet bees.

• Ants (Formicidae):

These include fire ants and harvester ants.

Very rarely bites from some insects can cause allergic reactions, such as:

• Mosquitoes.

• Bed bug.

• Kissing bugs.

• Deer flies.

What Are the Types of Reactions?

The severity of the allergy varies from person to person. The types of reactions are:

• Normal reactions reduce the swelling, redness, and pain present at and around the sting area.

• A local reaction may result in swelling in the region of insect sting. It may look alarming but is not more serious than a normal reaction. Local reaction peaks at 48 hours and slowly gets back to normal in five to ten days.

• The most serious reaction is the result of an allergic reaction which needs to be treated immediately.

What Are the Symptoms of an Allergy Caused Due to Insect Sting?

Some of the common symptoms are:

• Pain.

• Redness.

• Pimple-like spot.

• Mild to moderate swelling.

• Warmth.

• Itching.

Severe allergic reactions called anaphylaxis reactions are very rare, some of the common symptoms are:

• Troubled breathing.

• Hives that are red, itchy rashes, and to the area beyond the sting of the insect.

• Swelling is seen in the face, throat, or any region of the mouth or tongue.

• Wheezing.

• Troubled swallowing.

• Restlessness and anxiety.

• Rapid pulse.

• Dizziness and abrupt drop in blood pressure.

• Stomach cramps.

• Nausea.

• Diarrhea.

How Is an Allergy Caused by an Insect Sting Diagnosed?

If a person experiences an allergic reaction due to an insect bite, it is better to consult an allergist. The allergist should make note of the medical history and previous experience of an insect sting. Questioning should be based on

• Previous experience of insect sting, like how many times they have experienced the sting and where they have been stung.

• The reactions to those insect stings.

• Additional symptoms.

The allergist may conduct a certain test to diagnose allergies caused due to insect venom. Some of the tests include:

• Skin-Prick Test: In this test, a little amount of liquid that contains insect venom is placed over the forearm or back. A small prick is done using a sterile probe to allow the liquid to seep into the skin. If there is any reaction such as a raised reddish spot within 15 to 20 minutes that indicates an allergic reaction. After which a blood test is performed to identify the presence of IgE antibodies which are released during an allergic reaction.

• Intradermal Skin Test: In this test, a small amount of insect venom is injected into the skin. The area is examined after 15 minutes for any allergic reactions. This test is considered to be more accurate than the skin-prick test in finding the presence of IgE antibodies.

• Blood Test: If both the skin-prick and intradermal test results are negative then the doctors recommend a blood test.

How Are the Allergies Caused by Insect Stings Treated?

The allergic reaction caused is treated in two steps:

• If a serious reaction occurs, the first step is the emergency treatment of the symptom.

• Preventive treatment of allergy with venom immunotherapy is the second step.

  • Venom immunotherapy is a long-term treatment of allergies caused due to insect stings. This procedure is advised by the allergist and can even prevent a future allergic reaction. This procedure involves the gradual administration of venom into a person’s body to make the person resistant to the venom. This decreases the risk of future allergic reactions. In about a week or month people who fear the constant threat of serious reactions caused due to insect stings lead a normal life.

• Some severe and life-threatening allergic reactions require immediate treatment. Emergency treatment involves the administration of certain drugs like epinephrine, antihistamine, etc.

  • Injectable Epinephrine: These are self-administered drugs that are often recommended as emergency rescue medication for allergic reactions. Those people who have experienced allergic reactions earlier should carry epinephrine with them all the time.

Conclusion

Insect stings are very common conditions that do not necessarily cause an allergic reaction. The person who experiences an insect sting should be aware of the normal and allergic reactions. At times the allergic reactions caused due to insect stings can be life-threatening and require immediate treatment. There are many ways through which the allergic reaction caused due to insect stings is treated.