Allergy is defined as an exaggerated response of the immune system typified by immunoglobulin E (IgE) levels against the offending substance called 'allergen'.
Allergy shots work by vaccinating against inhaled or sting insect allergens. Small amounts of allergen vaccines are injected in gradually increasing doses to achieve the maintenance dose.
Immediate reactions - Occur within one hour of exposure. Reactions include: flushing, pruritus, urticaria, shortness of breath, chest tightness, angioedema, N& V, hypotension, etc.