Saturday, January 01, 2011
Bee, Wasp, and Hornet Stings
Hymenoptera stings cause toxic and allergic reactions. Toxic
reactions are called local reactions and result from local tissue
effects of the venom. These are often mild, lasting several hours,
but can be severe or even fatal if many stings occur. Allergic
responses are IgE dependent and present in a previously sensitized
individual as a local exaggerated reaction or a generalized
systemic (anaphylactic) reaction. Local exaggerated reactions may
be recognized when erythema, swelling, and itching extend beyond
the site of the sting. Anaphylaxis is a medical emergency requiring
prompt diagnosis and immediate therapy, preferably by individuals
trained in emergency medical services.
- Remove all embedded stingers as promptly as possible, as venom
continues to be injected after the stinger is detached from the
insect. Do not squeeze or pick up the stinger with the fingers;
instead, scrape laterally with a blade or use fine tweezers.
- Apply ice (not heat) early, and elevate and rest the affected
- Administer oral antihistamines such as hydroxyzine and a mild
analgesic if necessary.
- For severe reactions, analgesia and sedation may be
- For moderate to severe reactions, management as anaphylaxis as
described below may be necessary.
Local Exaggerated Reactions
- Treat as a local reaction as described above.
- Consider treatment with oral prednisone 1 mg/kg for 5
- Refer the patient to an allergist. Desensitization
immunotherapy may be considered.
- A medical alert bracelet may be indicated.
- Begin treatment immediately, and call for local emergency
- Place patient in supine position with legs elevated.
- Place a constriction band a few inches above sting site. The
band should be tight enough to obstruct venous but not arterial
- Apply ice to sting site to reduce venom absorption.
- Promptly administer epinephrine by subcutaneous injection (0.01
mL/kg of 1:1,000 solution up to a maximum of 0.5 mL per dose.
- Control airway and circulation if laryngeal edema and
- Referral to an allergist is recommended, and desensitization
immunotherapy should be strongly considered.
- The patient should wear a medical alert bracelet and carry an
emergency kit containing antihistamines, a bronchodilator, and an
- Educate the patient on how to avoid being stung (ie, know and
avoid areas where hymenoptera live and feed; avoid attractants
(cosmetics, perfumes, bright-colored 'flowery' clothing, and long
loose hair); and remove nests from the local environment (severely
allergic individuals should not do this themselves).
- Local reactions around the mouth or throat may lead to
respiratory compromise without a systemic allergic component.
Carefully observe these patients.
- Local exaggerated reactions around the eyes may be complicated
by severe ophthalmic sequelae (eg, atrophy of the iris, cataract,
globe perforation, or glaucoma). If eye symptoms develop acutely or
later, refer the patient to an ophthalmologist.
- Local bacterial infection (cellulitis) may closely simulate the
clinical picture of a local exaggerated reaction.
- Mastocytosis patients may have severe, life-threatening
reactions, which may or may not be true anaphylaxis.