Insect Stings

Insect stings are known to cause painful, even life-threatening reactions. These reactions are due not only from the insect’s venom but, more importantly, from the body’s allergic reaction to the sting. Potentially dangerous allergic reactions especially are common from the stings of bees (honeybees, bumblebees), yellow jackets, hornets and wasps.

How does the body react to the sting?

Allergic reactions to insect stings are either local reactions at the site of the sting or more generalized (systemic). Local reactions appear much like allergic reactions with the appearance of urticaria (wheals) and flares. Blisters and angioedema (localized swelling) may also be noted for more severe bites.

Generalized reactions are of more concern as they affect the entire body. The worst-case scenario is the onset of an anaphylactic reaction, which is life-threatening. This is seen in individuals who complain of difficulty in breathing or those who pass out after an insect bite. Systemic reactions appear rapidly following a sting, often with a few minutes of such a sting. Immediate medical care is needed for these cases.

What are the danger signs of a systemic reaction?

Apart from the local reactions of urticaria and angioedema, you should look for the following signs and symptoms:

• Difficulty in breathing or noisy breathing
• Throat tightness or hoarseness
• Dizziness
• Loss of consciousness

How are insect stings diagnosed?

The diagnosis of insect sting allergy is based on a history of insect bites and positive skin tests. In a skin test, a diluted version of insect venom is injected just beneath the skin (intradermal). Five types of venom are used: honeybee, yellow jacket, yellow hornet, white-faced hornet and Polistes wasp. A wheal larger than 5 mm in diameter with a flare (redness) 20 mm in diameter is a positive skin test.

How are insect stings treated?

Localized insect stings are treated similar to an allergic reaction. Antihistamines may be given to control inflammation and itching. Systemic reactions may be more difficult to treat and require immediate medical intervention.

How can systemic reactions to insect stings be prevented?

Venom immunotherapy prevents severe systemic reaction to insect stings. Very small doses of insect venom are given monthly for at least six months and then given at six- to eight-week intervals for five years. This is indicated for individuals living in areas with high concentrations of bees, yellow jackets, hornets and wasps.