Food Challenge 101: Learning Module
Have a food allergy? A food challenge test may be an option for your family.
A food challenge is a definitive procedure for testing whether someone can tolerate a specific food. During the challenge, your child will be given small, increasing amounts of the food in question and monitored very closely for a reaction.
For more information about a food challenge test and what to expect, start the module below.
Transcript of the Module
What is a Food Challenge?
A food challenge is a definitive procedure for testing whether your child can tolerate a specific food. The test can confirm if your child has a specific food allergy or determine if they have outgrown the food allergy. Only one food can be tested at a time.
During the challenge, your child will be given small — but increasing — amounts of the food in question and monitored very closely for a reaction. Your child will be in a hospital setting during testing, so if they have an adverse reaction, clinicians can respond quickly.
Which type of food allergies can be tested in a Food Challenge?
IgE-mediated food allergies
Most children who undergo food challenges have IgE-mediated food allergies and have had severe allergic reactions to specific foods like nuts, milk, eggs, seeds or other foods. Reactions to these foods are immediate and can affect multiple body systems, causing anaphylaxis, a potentially life-threatening allergic reaction. Anaphylaxis can cause hives, swelling, trouble breathing, vomiting, abdominal pain and loss of consciousness.
Food protein-induced enterocolitis syndrome (FPIES)
Food challenges may also be appropriate for children with food protein-induced enterocolitis syndrome (FPIES), a rare food allergy that affects the gastrointestinal tract. Unlike most food allergies, symptoms of FPIES do not begin immediately after eating, it can take hours before severe symptoms begin. Typical symptoms of FPIES include severe vomiting, diarrhea and dehydration. These symptoms can lead to other complications, including changes in blood pressure and body temperature, as well as lethargy.
Why would clinicians recommend a Food Challenge for my child?
There are several reasons clinicians may recommend food challenge testing for your child, including:
- To expand your child's diet. This is especially important when your child may be allergic to several foods and avoiding those foods.
- To evaluate foods that were removed from the diet or not introduced into the diet based primarily on positive allergy tests.
- When food is suspected to have caused a significant allergic reaction but specific allergy testing is negative.
- For FPIES, allergy test results are not always helpful, and a food challenge may be necessary to evaluate if your child has outgrown the food allergy.
What factors should be considered prior to a Food Challenge?
You and your child's primary allergist should agree that a food challenge is needed for any of the reasons discussed previously. You should also both agree that your child will realistically be able to participate in the challenge.
Several factors to consider:
- Risk of reaction
- Patient and family preference
- Nutritional importance of food
- Other issues
Risk of reaction
Your child should have at least a 50 percent chance of passing the challenge. Results of skin and blood testing and the history of the reaction to the specific foods are considered when estimating the risk of a current allergy.
Some families may prefer to wait until there is a greater chance of passing the challenge depending on the necessity in the diet of the food in question. Additionally, if your child is too anxious to ingest the food which they have been warned to avoid until this point, it may be better to postpone the challenge until they are mentally ready. Your child should know that the challenge site is a safe place to eat the food. It is helpful if you can explain this to your child and offer assurance.
Nutritional importance of the food
Food challenges may allow for expansion of the diet. This is especially important in a child whose nutritional status is negatively impacted because of the avoidance of multiple foods. If your child is allergic to a food that they will not continue to eat or be exposed to in the future, food challenges offer minimal benefit.
Other issues to consider
Food challenges are beneficial only when the food is expected to become part of the diet. Food allergies rarely recur after a tolerated food challenge, but can happen. In these instances, the recurrence of allergy was associated with infrequent ingestion or continued avoidance of the food.
How can I prepare my child for the Food Challenge?
Food challenges can be stressful for children and families. We are asking children to eat the very food they've been warned to avoid, and there is a risk of experiencing an adverse reaction.
What we want you to know — and to share with your child — is that our Food Challenge Center at Children's Hospital of Philadelphia is the safest place to try these foods. We are prepared for any reaction your child may experience and have a dedicated team of experts available to help.
Preparation for a food challenge includes:
- Medication changes
- Mental preparation
In the days leading up to your child's food challenge, certain medications may need to be stopped so they don't interfere with the test. Your child's healthcare team will give you specific instructions for your child, but below is a list of general guidelines.
Stop all antihistamines at least three days (72 hours) prior to the food challenge. This includes:
- Claritin (Loratadine), which should be stopped seven (7) days before the challenge
- Allegra (Fexofenadine)
- Zyrtec (Cetirizine)
- Xyzal (Levocetirizine)
- Benadryl (Diphenhydramine)
- Atarax (Hydroxyzine)
- Zantac (Ranitidine)
Combination medicines, like Extendryl and many over-the-counter cough and cold preparations also contain antihistamines. If you are not sure, please call our office at 267-426-8617 at least three (3) days prior to the challenge to double check.
On the morning of the challenge, do not give your child:
- Albuterol (Proventil, Ventolin®)
- Levalbuterol (Xopenex)
- Other rescue inhalers
Do continue giving your child daily maintenance asthma medications, such as:
- Singulair (montelukast)
- Nasal sprays (Flonase®, Nasonex®, Rhinocort®, Astelin, etc.)
- Inhaled asthma steroid medication (Flovent, Qvar®, Asmanex®)
Food challenge testing should not be performed if your child is sick or still symptomatic from a recent asthma flare. Additionally, if your child has been wheezing or having increased coughing within the past 1-2 weeks, rescheduling the challenge is recommended.
Eczema flares or other skin rashes may also interfere with the challenge.
If your child has these symptoms or you have questions, please call to discuss rescheduling the challenge at 267-426-8617. If your child gets sick within 24 hours of their food challenge, please call the main Allergy line at 215-590-2549.
It's understandable your child may have some anxiety leading into a food challenge. Reassure them that our office at Children's Hospital of Philadelphia (CHOP) is the one safe place to try the food. Begin to prepare your child to eat the food you've told them to avoid in the past.
Be sure to remind your child that:
- This is the safest place to try the food.
- There will be trained doctors and nurses at the bedside to monitor them.
- Medication will be immediately available to treat any severe allergic reactions.
- The food challenge could produce long-term benefits — potentially decreasing their sensitivity to the targeted food or determining they are no longer allergic to the item.
Preparing for the Food Challenge
For most foods, we will be dosing your child — at least initially — with a powdered version of the food. Please bring a food that your child enjoys (and tolerates) so we can mix the powder into that food.
Some example include:
- Low-fat pudding
- Low-fat yogurt without fruit
*A nurse will contact you before your child's first Food Challenge or if your child has not had a Food Challenge within the past 12 months. The nurse will make sure your child is not sick, ensure they're off antihistamines and have not started any new medications, and that they come with an empty stomach.
The Night Before
Your child cannot have anything to eat after midnight the night before their food challenge test. During this time, you may give your child clear liquids only. If your child is younger than 12 months, formula or breastfeeding is allowed.
Clear liquids include:
- Apple Juice
- Fruit juices with no pulp
- Iced Tea
- Popsicles or water ice without fruit chunks
The following are not clear liquids:
- Formula (for children older than 1 year old)
- Orange Juice
- Hot cocoa
Please ask about any food or drink not named on this list.
The morning of the Food Challenge
Your child may not have any breakfast the morning of the food challenge test. They may continue to drink clear liquids only.
If your child is still breastfeeding, they may continue to do so.
What to Bring to the Food Challenge
Due to limited space, we request that only 1-2 adults accompany your child to the food challenge testing. Please do not bring other children, and keep the items that you bring to a minimum, if possible.
What you should bring to the food challenge:
- Toy or distraction — You and your child will be here for several hours. Favorite toys, DVDs, books, and comfort items can help your child stay occupied.
- Snacks — Please bring about 32 oz. of clear liquids for your child to drink during the challenge. Juice boxes, Jell-O and other clear liquids as listed above are good choices.
- Lunch — Please bring lunch for you and your child. Your child may be permitted to eat lunch or snacks approximately one hour after the last dose of food is given.
- Challenge food — Bring the challenge food prepared exactly as described by the allergy nurse. Please also bring the packaging of the challenge food. Please bring a food that your child enjoys in which we can mix the powdered food to be tested. Some examples include: applesauce, low-fat pudding or low-fat yogurt without fruit. If there is another food that will allow incorporation of the powdered food that you feel would work better for your child, feel free to bring that food in as well.
- Change of clothing — Bring a new outfit for yourself and your child in case of vomiting.
- Insurance — Please bring all insurance cards and/or referrals.
At the Food Challenge
Please report to the fourth floor of CHOP's Wood Center by 7:30 a.m. on the day of your child's food challenge test. You will register at the desk and then be seated in the waiting room. An allergy nurse will meet you in the waiting room to bring you and your child to the Food Challenge Unit, where the food challenge will be performed.
On the Food Challenge Unit
The Food Challenge Unit includes eight designated areas where children can relax in comfortable, reclining chairs, watch individual TVs, talk with parents nearby, and draw a curtain for privacy. A nurse is within arms' reach of each bed and each child is monitored constantly.
Before the food challenge begins, a doctor will examine your child, particularly his or her breathing and skin condition. If we do not feel your child is well enough to safely participate in the challenge, we will reschedule the test. If your child has FPIES and is undergoing a food challenge, we will place an IV to deliver fluids in case your child becomes dehydrated due to vomiting.
Dosing details (IgE and FPIES)
At the start of the food challenge, your child will be given a small amount of the food being tested. Most foods will be in powder form and mixed with a food your child enjoys such as applesauce, low-fat pudding or low-fat yogurt.
Dosing for IgE-mediated food challenges and FPIES food challenges differ in the number of exposures to the food being tested and the length of time your child will be monitored at the hospital.
- Children undergoing IgE-mediated testing will receive five to eight doses of increasing amounts, about every 20 minutes.
- Children undergoing FPIES testing will only receive one dose of the food.
If your child has a severe reaction, the challenge is stopped and your child is considered allergic to that food. If your child can tolerate a full serving of the food, the challenge is stopped and your child is considered not allergic to that food.
Monitoring for adverse reactions
If your child develops any mild allergic symptoms, they will be treated in the Day Medicine Unit area with oral medication and/or epinephrine and monitored closely for any further symptoms.
In rare cases, a child may experience a very serious adverse allergic reaction during the Food Challenge. In such instances, the child will be treated with epinephrine to stop the reaction, and may be taken to the Emergency Department and/or admitted to the hospital.
Children with FPIES may experience vomiting during the Food Challenge. To ensure they remain hydrated, our team will deliver IV fluids, as needed, on the unit.
Monitoring after the challenge
Along with monitoring your child for the duration of their food challenge, clinicians will also monitor your child after the last dose of challenge food has been administered.
Children undergoing IgE-mediated testing will remain on the Food Challenge Unit for at least 2½ hours after the last dose of the food or the last adverse reaction. If there are no unexpected or adverse events, your child will likely be discharged around 1-2 p.m. If there are late adverse reactions, discharge may be later. Children who experience a significant reaction may be observed up to 4 hours or more.
Children undergoing FPIES testing are monitored for 4 hours after dosing. Because these children only receive one dose, they are often discharged between noon and 1 p.m. If the child has a severe reaction, they may remain on the unit longer or be transferred to another unit for longer term care.
Role of parent/guardian during testing
The most important role of a parent or guardian during food challenge testing is helping your child stay calm and relaxed. The best way to do this is for you to remain calm.
- The hospital is the safest place for your child to eat the food that may cause an allergic reaction.
- A team of expert clinicians are monitoring your child and will determine if additional medications and treatments — which are available at the bedside —are needed to stabilize your child.
Results of the Food Challenge
There are two primary results from an IgE-mediated or FPIES food challenge:
- Tolerate: Your child has successfully eaten the test food without severe reactions.
- React: Your child had a severe reaction and the test was halted.
For children with food allergies that produce immediate reactions, results of the food challenge — tolerate or react — will be determined before your child is discharged from the Food Challenge Unit, and next steps will be discussed.
In some cases, a child may be unable to complete the full dose of a tested food. If so, they will be monitored for 2.5 hours from the last ingestion/reaction. Your child's allergy result for this food is considered Indeterminate.
Once your child has completed the food challenge and returned home, there is a rare chance of a delayed allergic reaction. If this happens, immediately contact your child's allergist or the CHOP allergist on-call at 215-590-1000.
After the Food Challenge: What to Expect
What happens after a food challenge depends on if your child passed or failed the test.
Children who successfully tolerate a food challenge will be instructed to keep the food in their diet regularly. This may include eating the trigger food in small amounts each week.
Recurrence of a food allergy after challenge testing has been reported, but it is infrequent and is generally associated with a child's continued avoidance of the food allergen or not ingesting the food as prescribed.
Most children with IgE-mediated food allergies who tolerate the food challenge will be instructed by clinicians to begin eating the "dose" about three times a week.
Children who tolerate an FPIES food challenge will be instructed to eat the targeted food at slightly increasing dosages — determined by clinicians — over the next 9 days. If your child experiences an adverse reaction at any point, contact your child's allergist or the CHOP allergist on-call at 215-590-1000.
If your child experienced a severe reaction during the food challenge or was unable to complete the predetermined "dose" of the targeted food, they will be instructed to rest and take it easy for the rest of the day. Children with FPIES who have experienced significant vomiting may additionally need to be rehydrated with IV fluids. When your child feels better, they can be discharged home.
If your child reacts to a food challenge, clinicians will encourage you to follow up with your child's allergist in 6 months. At that time, clinicians can decide whether a follow-up food challenge is recommended for your child.
If your child experiences an allergic reaction at home after the food challenge, contact your child's allergist or the CHOP allergist on-call at 215-590-1000.
Does Not Complete (Indeterminate)
In rare cases, a child may be unable to complete the full dose of a tested food. If so, they will be monitored for 2.5 hours from the last ingestion/reaction. Your child's allergy result for this food is considered Indeterminate.
Children who receive an indeterminate result may return in the future to repeat the full dose of food.
If your child experiences an allergic reaction at home after the food challenge, contact your child's allergist or the CHOP allergist on-call at 215-590-1000.
Frequently Asked Questions
Where can I park for the Food Challenge?
For families participating in the Food Challenge, parking is available at the Wood Center behind the hospital at 3401 Civic Center Blvd., Philadelphia, PA, 19104. Get directions.
Please allow 15-20 minutes to park and find the registration desk.
Are there bathrooms on the Food Challenge unit?
Yes, there are two bathroom on the unit.
Where can parents get coffee near the unit?
Coffee is available to purchase on the first floor of the Wood Building, and at several nearby shops like Starbucks and Au Bon Pain.
What can kids do on the unit during testing?
Children can watch TV, play games, use electronic devices, talk, sleep or hang out in the playroom.
Can my child leave the unit during testing?
No. We need to closely monitor your child until they are cleared to go home. Children are able to walk around the unit, use the playroom and bathrooms, but must stay on the unit for the duration of the challenge.
Questions and Concerns
If you require referrals with your insurance, please remember to contact the primary care physician to obtain the necessary referral for your upcoming appointment(s). To avoid any billing issues, please contact your insurance company for specific coverage benefits.
Please call if:
- You are not certain about the medicine your child is taking.
- Your child is sick. If your child has a fever, asthma flare (coughing and/or wheezing), and/or eczema flare, food challenge testing cannot be done. If your child has these symptoms, please call to reschedule the test at 267-426-8617.