How long for an allergy to occur?

Can an allergy reaction or even anaphylactic shock occur after several exposures of the allergen?

• If I were allergic to peanuts. Ate peanuts throughout my life, then in one occurance could I have an all of a sudden intense allergic reaction like anaphylactic shock? Or would it most definitely only occur on the second exposure to peanuts? My throat and back of tongue feel tight and enlarged. My glands or some sort of muscle feels like it's pressing my throat so it feels tight and more closed. Doesn't hurt or itch, and it's my only symptom. My throat has been feeling tight for a long time sometimes worse than others. I'm trying to figure out if I have allergies or if this is something else.

• Answer:

  My daughter took an antibiotic for 6 days and did not have an anaphylactic reaction she developed serum sickness. It is an allergice reaction but in my opinion was much worse than an immediate reaction to a single exposure. As the medication was at the cellular level once her body converted and rejected the med it basically began destroying her body. She spent 7 months bedfast at age of 17 had never been sick... but to answer your question I think you can convert and become allergic to something at any time.