Allergies to Insect Stings and Bites

Allergies to Insect Stings and Bites
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Insects that Cause Allergies

Allergies to stings of insects of the order Hymenoptera (bees, wasps, ants) are common, affecting about 2% of persons (Lenhert n.d.). These insects do not bite humans; instead, they inject venom via a stinger on the abdomen. Some, such as bees, can sting only once, after which they die; others, such as wasps, can sting repeatedly and without injuring themselves.

Allergies to the bites of mosquitoes is known by anecdotal accounts to be possible in some individuals, particularly children between 2 and 4 years old (ACAAI 2000). Allergies to other insects can occur as well. For example, allergies to the bites of the true bugs of order Hemiptera (such as Triatoma, the assassin bug) are rare, but not unheard of (Lo Vecchio & Tran 2004).

Symptoms of Insect Allergy

The bites of mosquitoes, such as this Culex mosquito, can cause local reactions in children.

Allergic reactions to insect stings or bites can be of two types: local or systemic. A local allergic reaction occurs in the area of the sting or bite and is more severe than the normal response to the venom. It develops over 24 to 48 hours, with a large painful swelling 8 to 10 inches in diameter, and resolves within a week (Golden 2003).

Among systemic reactions is anaphylaxis, a rapidly progressing illness that can cause death within minutes if untreated. Anaphylaxis onset is typically faster when triggered by an insect sting than when caused by a food allergy because the venom is injected (Resuscitation Council (UK) 2008). Another potential non-systemic reaction is generalized urticaria, or hives occurring all over the body (Golden 2003).

Anaphylactic reactions to insect stings are more common in adults than in children. Children are more likely to experience only skin symptoms such as hives and swelling (Golden 2003).

A mosquito bite allergy that results in a severe local skin reaction is colloquially called “skeeter syndrome” by clinicians. It is easily confused with the skin infection cellulitis; testing for IgE and IgG antibodies to mosquito saliva is the only way to definitively differentiate between the two (ACAAI, 2000).

Treatment of Insect Allergy

Anaphylaxis should be treated with appropriate emergency measures. Other reactions can be treated like any other allergic reactions, such as with antihistamines. Topical hydrocortisone can reduce inflammation in localized reactions.

Over the long term, insect venom allergies respond well to immunotherapy, commonly called allergy shots. Immunotherapy can reduce or even eliminate the allergic response during the multi-year course of treatment and sometimes afterward. The efficacy of immunotherapy for insect stings is as high as 98% (Golden 2003).

References

Photo Credits

  • Honeybee photo: Waugsburg (Wikimedia Commons). Licensed under the GNU Free Documentation License.
  • Mosquito photo: United States Centers for Disease Control.

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