Food Allergy in the Breastfed Infant

Kirsi Järvinen-Seppo, MD, PhD


May 13, 2014

Diagnosing Food Allergy in a Breastfed Infant

The initial diagnosis of food allergy in a breastfed infant requires a detailed history, skin testing, and possibly serum testing. Positive tests are suggestive but not diagnostic of food allergy because false-positive results can occur, especially with atopic dermatitis. Disappearance of symptoms during maternal avoidance of trigger foods and reappearance during reintroduction of trigger foods to the maternal diet is diagnostic of food allergy.

The diagnosis of delayed-type gastrointestinal syndromes is not straightforward because a typical patient has undetectable food-specific IgE antibodies by skin prick or blood test. The diagnosis of FPIES or proctocolitis is based on clinical presentation.[9,23,24,25,26] In allergic EoE, endoscopy and biopsy showing an increased number of eosinophils establish the diagnosis.[22]

Food reintroduction (eg, an oral feeding test) may be done in an inpatient or outpatient setting under physician supervision.[27] Oral food challenges are also necessary during follow-up to determine whether the child outgrew the food allergy. During a food challenge, a serving of food is fed over 60-120 minutes, followed by a minimum of 2 hours (4 hours for FPIES) of observation before discharge. Oral food challenges for FPIES or after an episode of anaphylaxis are considered a higher-risk procedure because of the potential for hypotension, and are usually performed with secure intravenous access in place before beginning the challenge.

If an infant or small child has repeated episodes of severe emesis, with or without hypotension, upon ingestion of the food and is well when the implicated food is eliminated from the diet, the diagnosis of FPIES can be established on clinical grounds and an oral food challenge is not necessary. An oral feeding test may not be recommended in an infant who has had a recent severe anaphylactic reaction.


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