An extremely rare, but potentially life-threatening, allergic reaction is called anaphylaxis. Nuts and shellfish are common culprits here, Anaphylaxis occurs almost immediately after exposure to an allergen and manifests as'swelling of the face, lips, and tongue, which is a condition called angioedema. But also, there may be difficulty breathing and wheezing, rapidly growing hives, or uncontrollable vomiting or diarrhea. If you think your child is suffering from anaphylaxis, now is not the time to figure out what caused it! This can rapidly evolve into shock! So, call 911 IMMEDIATELY. AND, If you have an epi-pen, USE IT! Later, once your child is stable, you can consider potential culprits.