Final answer:
The most likely condition present in this child is a food allergy.
Step-by-step explanation:
The condition that is most likely to be present in this child based on the given information is a food allergy. The child has a history of allergy to nuts, and since he ate a cookie at the family picnic, there is a possibility that the cookie contained nuts. The symptoms of food allergies can include tingling or itching in the mouth, hives or itching, swelling of the lips or throat, wheezing or trouble breathing, abdominal pain, diarrhea, nausea or vomiting.