Repeated and usually severe, around two hours after the trigger food is eaten (could be one to four hours ). In undiagnosed cases of FPIES, this is often confused with viral infections.
Not as common as vomiting in acute FPIES: starting around five hours after the trigger food is eaten (could be up to 10 hours). In chronic FPIES, infants can have intermittent, watery diarrhea.
Children may be pale, limp, and less active than usual, due to vomiting.
In severe cases, the vomiting can cause dehydration that may lead to low blood pressure, poor circulation, and/or shock.
In chronic FPIES, poor nutrition can lead to delayed growth and development.
Some children experience relatively mild symptoms. Others, about 15%, will have extreme reactions requiring emergency treatment.