FPIES is a severe, non-immunoglobulin E associated food hypersensitivity reaction. Reactions are characterised by a clinical spectrum including protracted vomiting, pallor and lethargy which classically occur 1 to 4 hours following ingestion of suspected allergens. The most common eliciting foods are cow's milk, soya, fish and wheat. Diagnosis is confirmed upon elicitation of typical history. Resolution is typically confirmed via hospital based oral food challenges (OFCs). Considerable variance between allergy centres exists regarding practices for conducting FPIES OFCs. One such practice is prophylactic cannulation of patients deemed 'high-risk' prior to OFC commencement. We sought to audit rates of prophylactic cannulation in our tertiary paediatric allergy setting at St Thomas’ Hospital, London and compare them against rates of 'positive' (i.e. Failed) OFCs necessitating intravenous (IV) fluid administration.

We retrospectively reviewed an electronic database of FPIES OFCs performed since mid-2016 in order to gather data which was then collated on an Excel spreadsheet. Our primary outcome was identification of patients deemed ‘high-risk’ FPIES OFCs (as per EAACI guidelines) in whom prophylactic cannulation had been undertaken and in whom the cannula was then utilised to administer IV fluids when the patient had a ‘positive’ result. We hypothesised that this figure would be relatively low overall. We were also interested in any patients requiring IV fluids who had not had prophylactic cannulation. Secondary outcome measures looked into patient factors that might predict more severe OFC outcomes. Tertiary outcomes looked into rates of utilisation of other management strategies for FPIES such as intramuscular (IM) ondansetron and IV hydrocortisone. 

Our audit captured 35 FPIES OFCs from mid-2016 to December 2021. 9/35 (25.6%) were deemed via clinician based assessment to be ‘high risk’ OFCs that required prophylactic cannulation. Only 1/9 (11.1%) of these had a ‘positive’ outcome. Even so this 1 patient did not require IV fluids. Overall, only 3/35 (8.6%) OFCs had ‘positive’ outcomes requiring IV fluids. Interestingly, none of these 3 patients were correctly identified as ‘high risk’ nor had prophylactic cannulation prior to OFC commencement. Of the 3 ‘positive’ OFCs that went on to receive IV fluids, 100% reported a history of clinical reaction to the index food, 100% reported history of reaction with associated lethargy and 2/3 (66.7%) reported reaction requiring emergency department presentation. 7/7 (100%) of ‘positive’ challenges overall received IM ondansetron whilst only 1/7 (14.3%) received IV hydrocortisone.

In our audit, no patients cannulated prophylactically for FPIES OFCs required it for IV fluid administration. Prophylactic cannulation should be balanced against patient distress, especially in this predominantly paediatric population. Our audit highlights the importance of identifying factors that more accurately predict high-risk FPIES OFC outcomes.