Uppercase terms for longer names of ailments are very common. The ones mentioned here are the two most common mimics of true food allergy in infants.
Symptoms of FPIES (food protein-induced enterocolitis syndrome) are vomiting/reflux with diarrhea, and of FPIAP (food protein-induced allergic proctocolitis), colic and diarrhea. Blood (either visible or microscopic) in the stool is common with both.
FPIAP tends to occur at younger ages, often in the first two weeks of life, and occurs in infants who are exclusively breast-fed and those receiving formula. FPIES emerges later at around 5-8 months.
The allergic antibody IgE, which is the driving force for traditional food allergy and other allergic conditions, apparently isn’t involved.
The leading cause for both conditions is cow milk protein, accounting for 71% of FPIAP, and 79% of FPIES. The next most common cause is soy. This is especially problematic when the infant is bottle-fed as the next common protein base for infant formula (after cow milk) is soy. Much less common causes include eggs, lentils, grains, fish, meat and nuts.
Diagnosis confirmation can be obtained in a clinical setting by doing an oral food challenge where the suspected food is purposefully given after a period of avoidance, and then observing for the symptoms.
For a mother who is exclusively breastfeeding her baby, removing the food from the mother’s diet cures the problem.
Some good news is that more than 90% of children outgrow these problems by age 2. Unfortunately, about 20% of these afflicted children will go on to develop traditional food allergies.