Mechanisms Behind CMPA Development

Professor George Du Toit - Pediatric Allergist

The main difference between the two types of CMPA is the presence of antibodies. In IgE-mediated CMPA antibodies are present, whereas with non-IgE-mediated CMPA the immune system does not produce antibodies.

IgE-mediated CMPA

Usually occurs within a few minutes to ~2 hours after exposure to the dairy proteins (‘early reactions’).¹

The presence of these IgE antibodies means that cytokines and histamine are released, which trigger an inflammatory response. Symptoms associated with IgE-mediated CMPA are generally related to inflammation2 – itching, swelling, gastrointestinal problems like abdominal pain and diarrhea as well as difficulties breathing.

Non-IgE-mediated CMPA

These reactions are delayed and might not present for hours, or even several days after exposure to the implicated food (‘late reactions’)^3-5. It is a common condition in children - 50% of all cases of CMPA are reported to be non-IgE² but this does vary between countries.
Research indicates that the reaction is mediated by the T cells of the immune system⁴, but this mechanism is still not very well understood.

Other conditions such as lactose intolerance, Gastroesophageal Reflux Disease (GERD) or colic can be confused with CMPA especially when skin symptoms are also present.6,7

Mixed allergic reaction

Some infants can have mixed allergic reactions or combinations of early and delayed reactions³ with symptoms of both IgE-mediated and non-IgE-mediated allergy.