(1997; 132 pages) [French] [Spanish]
Bees, wasps, hornets and ants
Bees, wasps, hornets and ants are species of Hymenoptera. Their stings often cause intense and painful local reactions. In previously sensitized persons there is an associated danger of anaphylaxis, which can range in severity from mild pruritus and urticaria to potentially fatal shock characterized by severe hypotension associated with loss of fluid from the intravascular compartment, bronchoconstriction and laryngeal angio-oedema.
When the sting remains implanted in the skin, it should be carefully removed with a needle or knife-blade. Topical administration of calamine lotion may be of symptomatic value. Cooling of the affected area provides some relief when local reactions are severe. Systemic antihistamines and analgesics can be given to relieve pruritus or pain. Topical antihistamines have no proven value. Systemic corticosteroids may be appropriate if there are severe side-effects. Patients who sustain multiple bee stings at the same time are particularly at risk for systemic reactions, and should be seen and kept under observation at a hospital or medical post, whenever possible.
Any person who collapses, or who complains of wheezing, a feeling of anxiety or faintness, generalized itching, or tightness in the chest within approximately 1 hour of being stung by an insect should be treated as having anaphylactic shock. All such patients should receive an immediate intramuscular injection of 0.5-1.0 ml of epinephrine, 1:1000 solution. This promotes bronchodilatation and vasoconstriction and has a stimulant effect on the heart. It may also reduce the release of histamine and other vasoactive substances into the circulation by stabilizing the outer membrane of mast cells. Cardiac dysrhythmias and hypertension are likely to occur if over 2 ml of epinephrine is given within 5 minutes. When the response to epinephrine is transient, use of a plasma expander should be considered. Intravenous corticosteroids should not be administered initially, but may be used after the patient has received epinephrine for initial stabilization. There is no convincing evidence that antihistamines are of therapeutic value in established anaphylactic shock. Basic cardiopulmonary resuscitation should be started in the event of pulmonary or cardiac arrest.