In this webinar, Dr. Bharadia discusses how cow’s milk can cause allergy in infants. He defines food allergy as an adverse health effect arising from a specific immune response which occurs reproducibly on exposure to a given food. More than 170 different foods are known to cause IgE mediated reactions. Children tend to have more allergies than adults – about 12 percent children are allergic to peanuts, milk, eggs, fish or crustacean shellfish. Children are most susceptible to allergies due to egg, milk, soy and peanut. About 2.5 – 7.5 percent of infants have cow milk protein allergy (CMPA). The immediate reactions of CMPA could include Anaphylaxis, acute urticaria, and late reactions include Atopic dermatitis, chronic diarrhoea or poor growth.
Cow’s milk protein contains Casein (80 %) as 1-, as2-, Beta- and K-caseins. Whey (20 %) alpha and beta lactglobulin and others like bovine serum albumin, lactoferrin, and immunoglobulin. The early reactions from cow milk protein allergy are anaphylaxis, acute urticaria, wheezing rhinitis etc. The late reactions are chronic diarrhea, stool blood, iron deficiency anemia, gastroesophageal reflux disease, constipation, chronic vomiting infantile colic, poor growth (food refusal) and enterocolitis syndrome.
Investigations are done by taking a detailed history none of the test prove or disprove diagnosis of CMPA, skin prick test (using fresh food or extract), Radio Allergo Sorbent Test (RAST) patch testing which is still undergoing research and mucosal biopsy. Differential diagnosis is done by checking for food intolerance which might not necessarily be an immunologically mediated reaction (e.g., lactose intolerance), GERD, Metabolic disorders, Anatomical abnormalities, Celiac disease and other (rare) enteropathies, pancreatic insufficiency (such as in cystic fibrosis) and infections.
The diet for CMPA includes amino acid based diet which is non-allergenic, however has a bad taste and is expensive and not available in India. Extensively hydrolyzed formula (eHF) - 10% of CMPA react to eHF and need amino acid based formula. The role of Soy formula relates that soy protein is not hypo-allergenic. The incidence of soy allergy in soy formula-fed infants is comparable to that of CMPA in cow’s milk formula-fed babies. Soy may be considered in infants refusing to drink eHF and/or AAF, in infants beyond the age of 6 months provided there are no GI symptoms.
There is a growing evidence of the efficacy of oral immunotherapy with milk protein in the treatment of milk allergy. According to the current knowledge, such therapies induce desensitization as opposed to long-term tolerance and are currently investigational. Most children with food allergy will eventually tolerate milk, egg, soy and wheat; far fewer will tolerate tree nuts and peanut. A higher initial level of IgE is associated with a lower rate of resolution of clinical allergy over time. Earlier the age of intolerance, more is the chances of remission. Protocol in CMPA in nutshell is Dairy free diet for child and mother (if being breastfed) for 2-4 weeks. If improvement is seen in the infant then rechallange with cow’s milk after 3 months. If symptoms recur, then it confirms diagnosis. Rechallange after 1 year of age or after 6 months of the reaction.