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A closer look at insect stings, symptoms, treatment

Published Jun. 25, 2015

A recent news report serves as a reminder that some people experience severe allergic reactions as the result of an insect sting.

Dr. Kelly Gene Thomas, a 40-year-old University of Tennessee music professor, died June 7 from a wasp sting. It is unclear whether he had ever had a wasp sting reaction in the past.

Such severe reactions claim about 50 lives a year in the United States. Three percent of the population experiences a systemic allergic reaction to stinging insects. Most of these reactions occur in adults and in those without a prior history of a stinging insect reaction.

Having hay fever, food allergies or allergic asthma puts you at no higher risk than average of what are known as venom allergies. Nor does having a family member who has a stinging insect allergy.

Stinging insects are found in many places:

• Honeybees generally nest in hollow trees.

• Yellow jackets scavenge for food and often are found around trash cans and large trash bins.

• Hornets create nests that may hang from soffits of roofs.

• Wasps' nests, which look like honeycombs, usually are found on roof overhangs, behind shutters or in dryer vents.

• Fire ants, which are found throughout the Southeast, create underground nests with those telltale sandy mounds. (Their stings usually are in a semicircular pattern and often lead to pustules.)

Anyone who gets stung by a bee, wasp, yellow jacket, hornet or fire ant will experience pain, itching, redness and swelling — all normal reactions to the chemical properties of the venom. Symptoms generally subside in about an hour if there's just a sting or two, longer if there are more stings.

Less common is a larger area of swelling that can involve the nearest joint. Children who experience diffuse skin symptoms far away from the sting site, such as hives, need to be evaluated by an allergist, though rarely are they likely to develop a life-threatening reaction to a future sting.

Systemic allergic response symptoms, which usually occur within minutes of a sting, can include:

• Skin involvement (hives, flushing, swelling)

• Respiratory involvement (difficulty breathing, coughing, wheezing, shortness of breath, chest tightness)

• Cardiovascular involvement (chest pain, dizziness, low blood pressure, fainting)

• Gastrointestinal involvement (nausea, vomiting, diarrhea, abdominal cramping)

Skin symptoms are the most common but rarely occur alone in allergic patients.

Acute systemic symptoms should be treated with Benadryl. Ice packs and analgesics, such as Tylenol or ibuprofen, will help with pain and swelling.

Systemic symptoms involving the respiratory or the cardiovascular tract require immediate emergency care and injectable epinephrine.

Any symptoms other than localized swelling and pain should be evaluated by an allergist to identify a true allergy to venom. This may involve a basic evaluation, as well as skin testing.

Once a venom allergy is identified, patients can learn how to avoid situations where they might be stung. Because not all stings can be prevented, these patients should carry an injectable epinephrine device, commonly known as an EpiPen, and know when and how to use it. An identification bracelet or tag that makes others aware of the allergy is a good idea.

The best way to prevent a life-threatening reaction in allergic patients is through monthly venom allergy shots. Known as venom immunotherapy, in an effort to build resistance to the venom, allergic patients are injected with increasing amounts of dilute venom until the target therapeutic dose is reached. Allergic patients who are untreated have a 60 percent risk of a severe allergic reaction the next time they are stung. After six months of venom shots, that risk drops to 3 percent.

Venom injections can not only save allergic patients but also can give them their lives back, allowing them to enjoy the outdoors without the constant fear of a life-threatening reaction.

Dr. Mona V. Mangat is a board-certified allergist and immunologist at Bay Area Allergy & Asthma in St. Petersburg. Find her at bayallergy.com. If you have a question for the doctor, email her at bayallergy@gmail.com. Your question may be answered in a future column.