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Snakebite Allergic Effects

Snake venoms contain a variety of proteins, all of which are potentially able to stimulate an immune response in the snakebite victim. This is advantageous when raising antibodies in an animal, as part of the antivenom production process, but is not always useful in the human snakebite victim. After a first exposure, either through a bite, or possibly through breathing in venom particles (in the case of people working with venoms or "milking" snake venom), antibodies may develop against some or all venom components. If IgE antibodies develop, then the person is at risk of a major allergic reaction (anaphylaxis) on subsequent exposure to this or similar venoms. This is the same as a person with major bee sting allergy and the result can be just as lethal.

Not all cases of allergic reaction to snakebite are due to an IgE response, however. Some snakes, notably the European vipers, Vipera spp., can sometimes cause a severe "allergic" type response on first exposure. Typically, this is in the form of angioneurotic oedema, characterised by massive swelling of the lips, face and pharynx. The airway can be occluded, a potentially fatal complication. The precise reason for this response to a bite is not fully understood.