“Bee” Stings

“Bee” Stings

Dan Onion MD, MPH

Mt. Vernon/Vienna Health Officer

293-2076, dkonion@gmail.com

7/9/14

Not all “bee stings” are from real bees. Here in Maine, probably more stings are by yellow jackets, which are actually a type of ground-dwelling wasp and the most aggressive of local stinging insects. Since summer and fall are when most stings happen, I’ll review for you how to avoid, evaluate, and treat stings when they happen to you or a family member.  

Stings by bees (honey bees and bumble bees; insect order Hymenoptera, family Apidae) and wasps (yellow jackets, wasps, and hornets; insect order Hymenoptera, family Vespidae) are interesting. The stinger is a modified “ovipositor”, the female’s egg-laying organ; hence all these stinging pests are female. Stinging is used for both defense, and in the case of wasps, for prey immobilization as well. Honeybees deliver the most venom per sting, but make up for it by being less aggressive than yellow jackets, wasps, and hornets, which often inflict many more stings when they attack us in swarms.

Venom contains vasoactive amines including histamine and dopamine along with norepinephrine and kinins, which account for the painful red swelling and itching at the sting site, with swelling over 4 inches in diameter classified as “large”; sometimes raised, itchy rashes, called hives (medically: “urticaria”), occur over larger areas, distant from the sting site. Venom also contains protein enzymes, which contribute to local victim cell breakdown and pain but can also sensitize (make allergic) a person so that subsequent stings, weeks to years later, can result in potentially fatal hypersensitivity reactions (anaphylaxis) in 3% of adults and less than 1% of children. In other words, the human body can become its own worst enemy by releasing massive amounts of vasoactive amines in response to stings. This response causes shock (dangerously low blood pressure) and/or airway obstruction (severe asthma, swollen throat).

Small comfort though it is, sensitization to bee stings does not cause sensitization to wasp stings. But that’s not a lot of help because we can rarely choose or know whether we’re being stung by one insect family or the other. The size of a local reaction does not correlate well with later systemic hypersensitivity reactions; so don’t panic if your sting swelling has a 5-inch diameter, unless it is in your mouth (common with yellow jackets, which often feed on sugary foods/drinks). Once a person has had an allergic reaction, then they are highly likely to have another if stung by the same family of insects.

Local treatment for a sting for all should include a rapid search for a honeybee stinger (the size of a very small tick), which continues to pump venom for 20-30 seconds into the wound even after the bee has been brushed off. Look immediately and if found, scrape it off fast with a credit card or fingernail. Cold packs, antihistamines (25 -50 mg of diphenhydramine (like Benadryl ) every 6 hrs; half that in toddlers or small children), and aspirin can help the pain/itching. It may be reasonable to also get an EpiPen (prescription injectable epinephrine, at least 2 doses of 0.3mg in adults; these can be injected through clothing) or other form of injectable epinephrine to have around in case a future sting causes shock or respiratory symptoms.

Although most stings are inconsequential, some are serious and kill 40 or more people a year in the US. Two young acquaintances of mine here in Central Maine have died that way, both probably from yellow jackets. Any signs of allergic hypersensitivity reactions manifest by low blood pressure and/or shortness of breath should be immediately evaluated in an emergency room. After an anaphylactic reaction, even a mild one, a person should assiduously avoid places of likely contact with stinging insects; don’t keep bees and don’t mow lawns, drink soft drink cans outside, or pick raspberries where yellow jackets hang out. They should also carry at least two doses of some form of injectable epinephrine as described above, which is truly live-saving. Given the potentially fatal consequences of developing anaphylaxis, patients who have survived a systemic  allergic reaction should also be medically skin tested and desensitized with multiple injections of small amounts of venom over months-years. And, because they worsen an already bad situation, stopping chronic blood pressure medicines especially beta-blockers (like atenolol) and ACE inhibitors (like lisinopril and enalapril) should be considered.

I hope I haven’t scared you too much. Most stings are just a bother but a very small percent of people can die from them. I hope following the above guidelines can help you and yours be safe and enjoy the summer.


 

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