Describe the symptoms of an allergic reaction to food.

The symptoms of an allergic reaction to food can range
from a slight discomfort to a fatal reaction. These
include:

Oral Allergy Syndrome: This is a discomfort in the
mouth akin to an itchy or scratchy feeling. It is easily treated in a short while after
food is either swallowed or removed from the mouth.

Food
protein-induced enterocolitis syndrome: This results in vomiting and
diarrhea.

Eosinophilic esophagitis: The symptoms here are a
difficulty in feeding and loss of weight in babies; and a reduced appetite, vomiting,
heart burn, and difficulty in swallowing food in children and
adults.

Anaphylaxis: This results in a rapid drop in blood
pressure, inability to breathe, swelling in different areas all over the body, and
throwing up food. It can turn life threatening and requires immediate self medication by
injecting epinephrine and calling for professional medical
aid.

The information here has been referenced from the link
below, which should be referred for complete details.