Insect Allergy: Symptoms from Bee and Wasp Stings

What is insect allergy?

Insect allergy is a hypersensitivity to venom from bees and wasps that can cause allergic reactions from mild skin rash to life-threatening anaphylaxis. Approximately 3% of the population has insect allergy, with 0.3-0.8% of adults at risk of severe reactions.

Insect allergy usually means allergy to insect venom. It is mainly bees and wasps that can cause allergic reactions when they sting with their stingers. Wasp allergy and bee allergy are two different allergies. You can be allergic to bees but not to wasps, and vice versa.

Severe reactions to bee stings and wasp stings are uncommon. It is mainly adults who get such reactions, and in Sweden fatalities only occur in adults. Approximately 3% of the population has insect allergy, and severe reactions (anaphylaxis) occur in 0.3-0.8% of adults.

Why do I get insect allergy?

The risk of allergy to bees or wasps is greater if you are stung many times, for example if you are a beekeeper. However, there is no connection to other allergies. Children with pollen allergy or pet allergy do not have a higher risk of insect allergy.

More insects that cause allergies

Bumblebees and mosquitoes can also cause allergies when they sting, but it is more uncommon. Cockroaches secrete a substance that can cause allergies and breathing difficulties, in the same way as pollen and pets.

What symptoms does insect allergy cause?

Insect allergy causes symptoms such as hives all over the body, swelling of the face and lips, breathing difficulties, dizziness and nausea within 10-30 minutes after the sting. Typical warning signs are itching in palms, soles and scalp.

Insect allergy usually appears 10 to 30 minutes after you have been stung. These are common symptoms of allergy to insect stings:

• You become red and swollen around the sting site
• It itches and you get so-called hives on other parts of the body
• You become swollen in the lips and around the eyes

Symptoms of a severe reaction

In case of a severe reaction, you may also experience one or more of the following symptoms:

• You become weak and nauseous
• You have difficulty breathing
• Severe itching in the palms, soles and scalp – this is a typical warning sign
• You may experience abdominal pain, diarrhea and vomiting

Not all symptoms are due to allergy

You can experience symptoms from an insect sting without being allergic. Insect venom contains many substances and some are irritating to the skin. It is common for the skin to become red, itchy, swollen and painful where you have been stung.

If you receive many stings, it can cause a reaction similar to an allergic one, even if you are not allergic. An adult can tolerate quite a few stings without becoming seriously ill. However, if you are stung in the mouth or throat, you can become so swollen in the throat that it becomes difficult to breathe – even without an allergy.

Symptoms usually ease after 24 hours

If you are not allergic, the sting site usually swells and reddens more and more. Symptoms are often at their worst between 12 and 24 hours afterwards. Often the symptoms disappear after a day, but it can take up to a week.

When and where should I seek medical care?

Seek medical care immediately for facial swelling, hives spreading over the body, breathing difficulties or dizziness. Call emergency services for difficulty breathing, throat swelling or feeling faint. Use epinephrine auto-injector first if you have one, then call emergency services.

The vast majority of people who are stung by insects in Sweden do not need medical care. The symptoms usually go away on their own.

Contact a healthcare center or emergency clinic immediately if you have one or more of the following symptoms after an insect sting:

• You develop facial swelling
• You have been stung in the mouth or inside the throat
• You develop hives that itch and spread rapidly over the body
• You feel nauseous, dizzy or break out in cold sweat

If the healthcare center or emergency clinic is closed, seek care at an emergency department. If you have emergency medication at home, you should take it first and then call your local emergency number. It is good if you have someone with you until help arrives.

How can I avoid insect stings?

Avoid eating or drinking outdoors, never swat at bees and wasps, do not drink from opened cans, wear something on your head outdoors, and do not go barefoot. Avoid sudden movements and do not pick up fallen fruit.

There is much you can do to avoid being stung. Here are some examples:

• Avoid eating or drinking outdoors, as meat and sweet food or drinks attract insects
• Never swat at bees and wasps, and avoid sudden movements
• Do not kill a bee or wasp as they release scent signals that attract more insects
• Do not pick fallen fruit and be careful when working in the garden
• Do not drink from opened cans or bottles if you cannot see the contents
• Wear something on your head so insects do not get tangled in your hair
• Avoid going barefoot outdoors

How is insect allergy diagnosed?

Insect allergy is diagnosed through skin prick test where various substances are tested on the skin (results after 15 minutes) or blood test showing IgE antibodies against bee venom or wasp venom. The tests can distinguish between bee allergy and wasp allergy.

When you come to the healthcare for allergy investigation, you will be asked to describe what kind of insect stung you, what symptoms you experienced and how quickly the symptoms appeared.

Allergy tests can provide answers

It is common to do a skin prick test where various substances are tested directly on the skin. The result appears after approximately 15 minutes. You may also need to provide a blood test to see if you have allergy antibodies (IgE) in the blood against bee venom or wasp venom.

The tests can distinguish between bee allergy and wasp allergy, which is important to know which insects you must avoid and for potential allergen immunotherapy.

How is insect allergy treated?

Mild symptoms are treated with antihistamine and corticosteroid cream. For severe reactions, epinephrine auto-injector (EpiPen or Jext) is used immediately, followed by corticosteroid and antihistamine. Everyone with severe insect allergy should carry two epinephrine auto-injectors.

If you have mild symptoms, you can try treating with over-the-counter medications, such as antihistamine tablets. You can also apply cream or ointment containing hydrocortisone to relieve itching. Ask at a pharmacy for help choosing the right medication.

Treatment for severe symptoms

If you have had a severe reaction after an insect sting, you need to get medical care quickly. It is common to receive antihistamine and corticosteroid. Some may need to receive an injection of epinephrine.

You may need to stay a few hours at the clinic so that staff can see that you are doing well. If you have a very severe reaction to insect venom, you may need to be admitted to hospital. There you can receive fluids directly into the bloodstream and additional medication if needed.

You can treat yourself with emergency medication

If you have had a severe reaction to insect stings, you need to carry so-called emergency medication. This usually consists of two epinephrine auto-injectors (e.g. EpiPen or Jext), corticosteroid tablets and antihistamine.

What to do if you have a severe reaction

When you have a severe reaction, you should always use the epinephrine auto-injector first. The epinephrine can cause palpitations and make you feel shaky, but this usually goes away fairly quickly.

You may need to take the corticosteroid tablets immediately afterwards as it takes a few hours before they give full effect. The corticosteroid dampens the inflammation and reduces the risk of symptoms that may come later. You may also need to repeat the epinephrine auto-injector as the effect of epinephrine does not last very long.

It can also be good to take antihistamine which stops the allergic reaction in the body.

It is important that you learn in advance how to use the epinephrine auto-injector, so that you can handle it when you need to. Healthcare staff will show you how to do it. It is also good if someone close to you knows how to use the epinephrine auto-injector.

What is allergen immunotherapy and how does it work?

Allergen immunotherapy (allergy vaccination) provides 90-95% protection against severe reactions. Treatment involves injections once a week for 7-15 weeks, then every other month for approximately 5 years. Recommended primarily for adults who have had anaphylaxis.

If you have had a severe allergic reaction, you may sometimes receive allergen immunotherapy. It is also called allergy vaccination. The treatment is very effective and provides 90-95% protection against severe reactions.

How allergen immunotherapy works

First you receive an injection once a week for 7 to 15 weeks. After that you receive an injection approximately every other month. The treatment lasts around 5 years and usually makes you less sensitive to the allergenic substance.

Allergen immunotherapy is recommended primarily for adults who have had anaphylaxis. For children with only skin reactions, treatment is usually not necessary as children rarely develop severe reactions.

Medication when you are pregnant or breastfeeding

You can use certain antihistamine tablets when you are pregnant or breastfeeding. Ask at the pharmacy or contact a doctor.

You should always use your emergency medication if you have an allergy to wasp stings or bee stings and experience an allergic reaction. It is more risky for the baby that you have a severe allergic reaction than to be affected by the medication.

Allergen immunotherapy involves a risk of allergic reactions that can harm the fetus. The risk is greatest at the beginning of treatment. Therefore, it is not recommended to start immunotherapy when you are pregnant. However, if you are already undergoing treatment, you can continue with it if you become pregnant during that time.

How do allergic reactions work?

Allergic reactions occur when the immune system produces allergy antibodies against a substance (allergen). When the allergen comes into contact with the antibodies, histamine and other irritating substances are released that cause the symptoms. Almost one-third of Sweden's population has some type of allergy.

Allergy means a hypersensitivity to a certain substance. Allergy usually develops in childhood, but adults can also develop allergies. Almost one-third of Sweden's population has some type of allergy.

Substances that cause allergies are called allergens and can be found everywhere in the environment. They can be substances you ingest through food, air, skin contact or in venom from bites.

Allergic symptoms occur when the immune system reacts to certain substances to protect the body against them. The immune system then produces allergy antibodies that attach to certain cells in the body. The allergens then stick to the antibodies and cause the cells to release histamine and other irritating substances. It is these substances that trigger the allergic reaction.