Food Allergy Symptoms More Condition_symptoms How Long Does It Take For Symptoms Of A Food Allergy To Show?

How long does it take for symptoms of a food allergy to show? - food allergy symptoms more condition_symptoms

I believe that feeding the introduction of peanut butter to my son. There are no nut allergies in my family or my husband to the family. If yes, by chance, allergies, how long after ingestion, symptoms appear? In a few minutes / hours / day, etc. ..?
In addition, allergic reactions to peanut butter always anaphalactic? If so, how long I should be in the emergency room if you have a reaction?

Thanks in advance! :-)