Hymenoptera order includes wasps, bees, hornets and moskitoes. In our area, these insects are around mostly during Spring, Summer and early Autumn.
The most aggressive stinging insects are vespid wasps (including bald-faced hornets and other yellow jackets). All of these insects aggressively defend their nests. The stings of most of these species can be quite painful.
Venom is injected when the insect stings. The active portion of the venom is a complex mixture of proteins, which causes severe immediate local allergic reactions (IgE induced). In case of multiple stings, a toxic reaction may even occur.
There are 2 possible allergic reactions to wasp or bee venom:
Occurs in the following hours. May be largely spready and accompanied by edema (sometimes on a whole limb). Not a life-threatening reaction unless its location is unfortunate (i.e. mouth, neck) thus causing mecanical problems and potentially asphyxiation.
Occurs in the following minutes. The reaction is induced by specific IgE (antibodies) against the insect.
This is a life-threatening reaction.
Reaction is systemic: angioedema and urticaria (eventually in larynx), broncho-spasma (asthma), low blood pressure with fainting and cardiorespiratory failure. Paraesthesia, paresis, digestive trouble often come with the reaction.
Sometimes, only low blood pressure and fainting occur, with no other symptoms. Quincke’s edema (larynx edema) can occur and cause asphyxiation.
Such reactions are often repeatable, meaning a patient having suffered edema-urticaria the first time will probably have one the second time.
Unfortunately, for 15% of patients, reactions become more and more severe. Death occurrence due to severe reaction is also connected to age and cardio-respiratory pathologies.
Patient’s reaction history, classified by seriousness and, if possible, identification of the insect having caused it, will enable initial diagnosis. This is later confirmed by skin prick-tests (standard and very reliable) and by a blood test calculating the amoung of specific IgE against these insects.
If the insect to be blamed for the reaction is not formally identified, prick-tests and blood tests will clarify which venom or venoms the patient is allergic to.
When allergic reaction is accompanied by bronchospasma and fainting, desensitization is a formal indication.
After 3 years of desensitization, skin prick-tests will be renewed. If still positive, treatment is to be continued another 2 years.
At the end of the 5 years of treatment, desentitization is complete, unless skin prick-tests still are positive and if there is a specific risk factor (i.e. bee-keeper, apiculturist).
Generally speaking, desensitization has excellent results and provides good protection.