Case Study by ashley stoner , md 1 ; matthew c . bell , md 2 , 3
1
University of Iowa Hospitals and Clinics , Department of Allergy / Immunology , Fellow-In-Training , Iowa City , IA
2
Hedberg Allergy & Asthma Center , Fayetteville , AR & Rogers , AR
3
University of Arkansas for Medical Sciences , Department of Pediatrics , Division of Allergy & Immunology , Little Rock , AR
Food Protein Induced Enterocolitis ( FPIES ): An Underrecognized and Often Misdiagnosed Pediatric Condition
Case Presentation
A six-month-old previously healthy infant presents to a walk-in clinic with acute onset vomiting that began 6 hours prior to presentation . She is exclusively breast-fed except for occasional oatmeal mixed with breast milk . The patient ’ s mother reports that vomiting began about 2 ½ hours after she introduced a new iron-fortified multigrain cereal containing oat , barley , and wheat . The mother estimates that the child has vomited at least 8 times and expresses no interest in nursing . She has no evidence of urticaria , angioedema , or difficulty breathing . Additionally , the mother notes that the child has been somewhat lethargic since the vomiting episodes started and had an episode of mucous-containing diarrhea on the way to the clinic . Her medical history is significant only for mild eczema . Physical examination reveals a pale , somewhat listless child with mild tachycardia , delayed capillary refill , and no evidence of rash .
This patient has a clinical presentation consistent with food protein-induced enterocolitis syndrome ( FPIES ). FPIES is a non-IgE mediated food hypersensitivity that presents with intractable , forceful emesis that begins 1-4 hours after ingesting the offending agent with associated lethargy , pallor and sometimes watery diarrhea – occasionally with mucus or blood . 1 , 2 On some occasions , volume loss can be significant enough to cause hypotension and mimic shock leading to a potential medical emergency .
Background / Diagnosis
FPIES is pathologically different from
IgE-mediated diseases , although some patients with FPIES have concurrent atopic disease as well . Skin prick testing and serum IgE testing for foods are not helpful in diagnosis of FPIES but can help rule out IgE-mediated food allergy if the history is not clear . 2 The delayed onset of symptoms , lack of typical IgE-related symptoms consistent with anaphylaxis , and poor recognition by the medical community can make the diagnosis of FPIES difficult . 1
Diagnostic criteria were established in 2017 by the American Academy of Allergy , Asthma and Immunology with International Consensus Guidelines . 1 FPIES can be confirmed by patient having one major criterion and three or more minor criteria fulfilled [ see Table I ] 1 . In most cases , history alone is sufficient for diagnosis and there are no laboratory tests or radiographic studies to confirm the diagnosis of FPIES .
FPIES was officially defined in the mid- 1970s . 1 Prior to this there were no official uniform diagnostic criteria . Therefore , the prevalence estimates vary widely . Katz et al described CM-induced FPIES with an incidence of 3 per 1000 newborns over 2 years in a prospective birth cohort . 1 However , the incidence seems to be increasing and health providers need to be familiar with the manifestations , diagnostic criteria , and management of this disease 1 .
The most commonly reported FPIES triggers in the United States are cow ’ s milk ( CM ) and soy , though a trend towards solid foods , particularly grains , has been noted in some areas . 1 , 3 , 4 CM and soy FPIES typically present at an earlier age than solid food FPIES . 1 The most common solid food offenders for FPIES are rice and oat , likely because they are typically the first solid foods introduced . 1 Approximately 50 % of infants who experience CM FPIES will react to soy and vice versa 1 . Up to 80 % of children with solid food FPIES react to multiple foods and about 65 % of these were previously diagnosed with either CM or soy FPIES . 1 Other implicated solid foods include avocado and banana3 . The typical age of presentation for FPIES is 2-7 months of age , when either formula and / or solid foods are first being introduced . 1 , 2 , 3 , 4 Infants that present prior to 2 months of age are more likely to present with bloody stools and failure to thrive . 1 Interestingly , exclusive breastfeeding has been shown to have protective properties against FPIES . 1 It is rare for a child to present with FPIES after 1 year of age , though there are case reports of FPIES developing even into adulthood . 1
Pathophysiology
The pathophysiology of FPIES is poorly understood . Studies have observed many different inflammatory mechanisms at work during FPIES reactions , indicating that the underlying immune response is quite complex . Some studies have shown that activation of the innate immune system ( monocytes , natural killer cells , neutrophils ) follows FPIES challenge , while others have pointed to evidence of a T-cell mediated inflammatory response . 1 , 5 , 6 , 7 Whatever the underlying cause of the inflammation , the result is an increase in intestinal permeability leading to significant fluid shifts . Attempts to use readily available laboratory studies to identify FPIES patients have largely failed given the paucity of concrete knowledge regarding the underlying pathophysiology . While
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