Allergic reactions can be localised or systemic. If they are systemic (involve more than two body systems) this is classed as Anaphylaxis and an Epi-pen is highly recommended to be used by a first aider.
Anaphylaxis is the most severe form of an allergic reaction and is life-threatening. Epipen is given to a large muscle, often the outer aspect of the mid thigh. Can be given outside of clothing (not over the seem)
If its going to happen, usually occurs in the first 20 mins after exposure
If the Epi-pen is successful the casualty MUST still go to hospital as they need to be medically observed for at least 4 hours (rebound effect)
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