How many exposures before an FPIES reaction?
Many FPIES feeding plans count exposures: each time a new food is given. Parents often ask how many it takes. The 2017 international guidelines give no number, and the plans hospitals hand out differ. What one large study does show is when first reactions tend to come.
This page will not tell you how many exposures to give, how much, or how far apart. That is a plan to make with your child's doctor.
The first time, or later
Children's doctors across Australia reported the infants they saw with FPIES from 2012 to 2014: 230 infants in all. For 311 foods that brought on a child's first reaction, they recorded how many times the child had eaten that food before.
- 51% The first known time (158 of 311)
- 14% After 1 time without symptoms (45 of 311)
- 11% After 2 times without symptoms (33 of 311)
- 24% After 3 or more times without symptoms (75 of 311)
311 foods that brought on a child's first FPIES reaction. Australia, 2012–2014.
About half of these first reactions came the first known time the food was eaten. The other half came after the food had already been eaten without symptoms: about one in four after three or more times.
"Known" matters. The FPIES Foundation's medical advisers note that a reaction often comes on the first known exposure, presumably because of earlier small exposures nobody noticed.
Why a food is given more than once
Feeding plans give a new food more than once, and leave several days before the next new food, to watch for a reaction.
A 2021 review by FPIES dietitians and allergists points to the findings above when it discusses how quickly to introduce new foods.
How many times, how much and how far apart differ from plan to plan. Some count every serving, some count days, and one counts weeks. The 2017 international guidelines give no number of exposures.
A food trial and a food challenge
"Food trial" is an everyday phrase. The FPIES Foundation's medical advisers note that it has no formal medical definition.
A food challenge is different: a measured feeding given under a doctor's supervision. It is the main test doctors use to diagnose FPIES to a food.
Write each one down, even the quiet ones
FPIES reactions usually begin one to four hours after the food is eaten, so the time of each exposure matters.
Specialists ask how many times a reaction has happened, whether it was the same each time, and how long after the food it began. A line for every exposure answers that, including the times nothing followed.
Keeping an FPIES food trial logA free printable log and chart
Every food on one page, a box for each exposure. Free, no sign-up.
Download the printable (PDF)Tummy Tales keeps the same record
- Works out the time between a meal and a reaction
- Reminds you, in your own words, at the time you choose
- Makes one plain report for the appointment