Anaphylaxis is a serious, life-threatening allergic reaction and can present with wheezing, chest tightness or trouble breathing, loss of consciousness, or feeling faint.
If two of the following symptoms occur, consider anaphylaxis and inject epinephrine, and seek emergency care:
Hives — Rash, or red, itchy skin
Stuffy or itchy nose, sneezing, or itchy and teary eyes
Vomiting, stomach cramps or diarrhea
Angioedema or swelling
Hoarseness, throat tightness or a lump in the throat
FARE has an excellent list of words children may use to describe a food allergy reaction that can be found here.