Know what to look for. Symptoms of an allergic reaction vary from baby to baby, and can range from mild to severe. It’s important to know what to look for and how to address a potential reaction if it occurs. Before you introduce potential allergens into your baby’s diet, know how to recognize the signs of an allergic reaction. Severe reactions may include any of the following, either alone or in combination: 1️⃣ Lungs: shortness of breath, wheezing, repetitive cough 2️⃣ Heart: pale/bluish skin,