Very variable... Eggs are one of the most common allergy-causing foods in children. Symptoms can occur minutes to a few hours after eating eggs or foods containing eggs. Signs and symptoms range from mild to severe skin rashes, hives, nasal inflammation, and vomiting or other digestive problems. Rarely, egg allergy can cause anaphylaxis — a life-threatening reaction.
Depends. Symptoms of food allergy (egg included) may include hives, cough, shortness of breath, eczema, wheezing, vomiting or diarrhea.
Hives, swelling, etc. Symptoms of food allergy are the same regardless of the food - immediate (anaphylactic) hives around the mouth, 2 hours later all over. Swollen lips, tongue, face, eyelids. Expect nausea, vomiting, abdominal pain, choking, coughing, difficulty breathing, sense of doom, lightheadedness, loss of consciousness. When not life-threatening as above, chronic exposure may exacerbate eczema.
Multiple symptoms. Symptoms of allergy to egg (or any food) may include rash/hives, eczema, shortness of breath, cough, throat discomfort, wheezing, vomiting or diarrhea, lip/tongue swelling, etc.