Insect allergy occurs when exposure to an insect results in an adverse or abnormal reaction. These exposures can be in the form of an insect sting or bite, or can occur when susceptible individuals breathe air in locations where allergy-causing insects live.
Causes
Stinging insects include:
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Honeybees
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Yellow jackets
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Hornets
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Wasps
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Fire ants
Biting insects include:
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Blackflies
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Fleas
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Horseflies
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Mosquitoes
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Kissing bugs
Insects that cause respiratory allergies include:
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Cockroaches
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Dust mites
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Midges
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Lake flies
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Caddisflies
Risk Factors
A risk factor is something that increases your chance of getting a disease or condition.
Risk factors include:
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Age: young children
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History of other types of allergies, including hay fever
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Family history of allergy
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Occupations that expose you to insects
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Living conditions that expose you to insects, or dust containing insect allergens
Symptoms
Symptoms of allergy to biting and stinging insects usually involve severe swelling and symptoms local to the area of the bite. Anaphylaxis occurs when extreme allergy to a stinging insect causes systemic symptoms that may be life-threatening. Symptoms of exposure to insects that cause respiratory allergies can cause nasal congestion and asthma-like symptoms.
Local symptoms affect the area around the bite or sting, and can include:
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Skin rash
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Hives
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Itching
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Swelling
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Redness
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Hotness
Anaphylactic symptoms can include:
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Skin rash, hives, itching, swelling in areas away from the sting site
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Swelling of lips, tongue, face, throat, and eyelids
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Difficulty breathing, shortness of breath, coughing, wheezing
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Dizziness, fainting
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Severe drop in blood pressure
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Respiratory and/or cardiac arrest
Symptoms associated with exposure to insects that provoke respiratory allergies include:
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Runny nose
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Sneezing
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Coughing
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Wheezing
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Difficulty breathing
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Shortness of breath
Diagnosis
The doctor will ask about your symptoms and medical history, and perform a physical exam. Most diagnoses are based on a history of an allergic reaction after a sting.
Tests include:
Scratch Skin Test
The doctor will put a dilute extract of the insect's venom or protein from the insect on your forearm or back skin. If there is swelling or redness, an allergic reaction may be present. Using the results of the skin test in combination with your history of symptoms, the doctor will make the diagnosis. This test should not be used if you are severely allergic or have eczema.
RAST or ELISA Test
In these cases, the doctor may order blood tests (RAST or ELISA). These tests measure the level of insect-specific IgE in the blood. IgE is a type of protein that the body produces when it comes in contact with something it is allergic to. The presence of IgE in the blood may indicate an allergy.
Treatment
If you are having trouble breathing, call for emergency medical help immediately.
Treatment may include:
Epinephrine–injected immediately in the event of a severe, life-threatening insect sting allergy (anaphylaxis)
Antihistamine Medications–used to decrease swelling and itching
Ice–Applied to local area of sting or bite to decrease swelling
Corticosteroid Medications–given for more severe swelling, itching, nasal congestion, and sneezing
Bronchodilators–inhalers that can be used to decrease asthma-like symptoms, such as wheezing, coughing, and shortness of breath
Venom Immunotherapy–a series of allergy shots to gradually desensitize you to insect stings
Prevention
To reduce your chance of having an allergic reaction to either biting or stinging insects:
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Avoid situations where you may be around stinging insects.
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Be very careful when doing yard or garden work, or when hiking in the forest.
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Don't walk barefoot.
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Don't wear scented products (perfumes can attract stinging insects).
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Keep exposed skin to a minimum.
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Consider immunotherapy (allergy shots) to lessen your reaction to insect stings.
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Carry a bee sting kit with you at all times. These contain self-injectable epinephrine.
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Wear a medical alert bracelet or necklace to inform others of your allergy.
To reduce your chance of having an allergic reaction to insects that provoke respiratory responses:
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Avoid having carpeting, curtains, or other fabric that may gather dust in your home, especially in the room where you sleep.
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Vacuum and wet mop your floors frequently.
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Wash your linens in very hot water regularly.
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Cover mattresses and pillows in allergy-proof covers.
RESOURCES:
American Academy of Allergy, Asthma, and Immunology
http://www.aaaai.org
American College of Allergy, Asthma, and Immunology
http://allergy.mcg.edu
Joint Council of Allergy, Asthma, and Immunology
http://www.jcaai.org
References:
Adkinson NF. Middleton’s Allergy: Principles and Practice, 6th ed. Philadelphia, PA: Mosby-Year Book; 2003.
American College of Allergy, Asthma, and Immunology website. Available at: http://allergy.mcg.edu. Accessed October 13, 2005.
Middleton's Allergy: Principles and Practice, 5th ed. Philadelphia, PA: Mosby-Year Book; 1998.
