Food Challenge Allergy Test

What is a food challenge?

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.

What are the indications for doing a food challenge?

  • To allow expansion of the diet, especially when several foods are under consideration and are therefore being avoided
  • To evaluate food 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 food protein-induced enterocolitis syndrome (FPIES), allergy test results are not always relevant, and food challenge is necessary to evaluate if the allergy has been outgrown

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 above. You should both also agree that your child will realistically be able to participate in the challenge.

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.

Patient/family preference

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 are able to 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 allergy may rarely recur after a negative challenge (passed food challenge). The recurrence of allergy is associated with infrequent ingestion or continued avoidance of the food in question.

How do I prepare for the food challenge?

Medications

Antihistamines

Stop all antihistamines at least three days (72 hours) prior to the challenge. These include Claritin® (loratadine), Allegra® (fexofenadine), Zyrtec® (cetirizine), Xyzal® (levocetirizine), Benadryl® (diphenhydramine), Atarax® (hydroxyzine).

Combination medicines, like Extendryl®, and many of the over-the-counter cough and cold preparations may contain antihistamines. If you are not sure, please call our office at least three days prior to the challenge to double check.

Asthma medications

Do not give albuterol (Proventil®, Ventolin®), Xopenex® or other rescue inhaler on the morning of the challenge. Continue giving daily maintenance asthma medications.

Do continue: Singulair®, nasal sprays (Floanse®, Nasonex®, Rhinocort®, Astelin®, etc.), inhaled asthma steroid medication (Flovent®, Qvar®, Asmanex®)

Illnesses

We should not perform the challenge if your child is ill or still symptomatic from a recent asthma flare. If your child has been wheezing or having increased cough within the past one to two weeks, it may be best to reschedule the challenge. Eczema flares or other skin rashes may also interfere with the challenge. If your child has these symptoms or you have questions, please call us at 267-426-8617 to discuss rescheduling the challenge.

If the challenge is within 24 hours, please call the main Allergy line: 215-590-2549.

Mental preparation

It is understandable to have some anxiety about food challenges. Reassure your child to understand that our office is the one safe place to try the food. Begin to prepare for the idea of eating something you have told your child to completely avoid in the past.

Challenge food preparation

We will be dosing your child at least initially with a powdered version of the food. Please bring a food that your child enjoys in which we can mix the powdered food. Some examples include: applesauce, low-fat pudding or low-fat yogurt without fruit.

A nurse will contact you before the challenge to discuss exactly what type of food to bring for the challenge and how it should be prepared. Please also bring in the package that the food came in.

Night before the challenge

Your child may not have anything to eat from midnight the night before the test and no breakfast the morning of the test. During this time, you may give your child clear liquids only. If your child is still breastfeeding, they may continue.

Clear liquids include: water, apple juice, fruit juices with no pulp, iced tea, Gatorade®, Jell-O®, popsicles or water ice without fruit chunks. The following are not clear liquids: Milk, formula, orange juice, soda and hot cocoa. Please ask about any food or drink not named on this list.

PLEASE CALL IF:

  • You are not certain about the medicine your child is taking.
  • Your child is sick. If there is fever and/or asthma flare (coughing and/or wheezing), and/or eczema flare, the food challenge cannot be done.

If your child has these symptoms, please call to reschedule the challenge at 267-426-8617.

Can my child have breakfast before the food challenge?

No. Remember that your child may not have anything to eat starting at midnight the night before the challenge. Clear liquids the morning of the challenge are OK. If your child is still breastfeeding, they may continue.

Who can come to the food challenge?

Due to limited space, we request that only one to two adults accompany your child. Please do not bring other children, and keep the items that you bring to a minimum if possible.

What should I bring to the food challenge

  • Toy/distractions: You and your child will be here for several hours. Favorite toys, DVDs, books, etc., will help to stay occupied.
  • Snacks: Please bring about 32 ounces of clear liquids for your child to drink during the challenge. Juice boxes, Jell-O® and other clear liquids as listed above are some good choices. 
  • Lunch: Please bring lunch for you and your child. Your child may be permitted to eat lunch/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. Some examples include: applesauce, low-fat pudding or low-fat yogurt without fruit. If there is another food you feel would work better for your child and can be incorporated with the powdered food, feel free to bring that food as well.
  • Change of Clothing: Bring a change of clothing for you and your child in case of vomiting.

What will happen on the actual day of the food challenge?

Registration

Please report to the third floor of the Wood Building by 7:30 a.m. 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 is performed.

Pre-challenge evaluation

Before the challenge begins, the doctor will examine your child, particularly their breathing and skin condition. If we do not feel that your child is well enough to safely participate in the challenge, we will reschedule the challenge. (Note that your child may need IV for FPIES challenges.)

Food challenge dosing

At the start of the challenge, a small amount of the food will be given to your child. Every 20 minutes, an increasing amount of the food will be given for a total of 5-8 doses (1 dose only for FPIES). If the child has a 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.

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. Rarely, if there is a very serious adverse allergic reaction, your child may be taken to the hospital or emergency room.

Monitoring after the challenge

We will monitor your child for 2½ hours after the last dose of the food or the last adverse reaction. If there are no unexpected or adverse events, you 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 four hours or more.

During the Food Challenge Test: The most important role of a parent or guardian during the test is to help your child stay calm and relaxed. The best way to help your child stay calm is for you to stay calm.

What can I expect after the challenge?

Once at home, there is a rare chance that your child will have a delayed allergic reaction to food challenge. Contact your allergist (or the allergist on call at 215-590-2549 and ask for allergy physician on call) immediately if this happens.

If your child does not experience a delayed allergic reaction, we recommend they consume the specific food in their diet around three times per week.

Recurrence of allergy has infrequently been reported, and these episodes were associated with infrequent ingestion or continued avoidance of the food in question.

If you have any questions or concerns about the food challenge, please call: 267-426-8617.  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.