There are four primary reasons for doing a food challenge:

1. Determine whether the wrong food is suspected as the cause of symptoms.

2. Prove that a food is NOT the cause of symptoms.

3. Verify whether a patient has outgrown food allergies.

4. Discover the degree of sensitivity.

Learn more about why food challenges are effective here.

Please follow these directions when getting ready for this test.

• We may ask you to bring in a specific food for the food challenge. Please bring the food the morning of the test.  You may also be asked to bring a favorite food in which to place the food to be challenged.

• Usually you eat only the food being provided during the food challenge. Please discuss this with your doctor or nurse and do not eat other foods during the food challenge.

• If you are sick, please call to cancel the food challenge. This includes cold symptoms, diarrhea or a stomach ache, a body rash or atopic dermatitis flare. The food challenge results may be hard to interpret if these are present. If you have any questions, please call to speak with a nurse. 

• If you are given a sedating antihistamine for a reaction during the food challenge, you may not be able to drive. Please make sure to have a family member or friend available to take you home in case this were to occur.

• Please check in at the time your test is scheduled.

Some medicines might affect the results of the food challenge and will need to be stopped before the testing is done unless your doctor tells you otherwise. You’ll find information on medicines in the next FAQ.

All antihistamines will affect the results of some of these tests and need to be stopped before the testing is done. If you have any concerns about stopping antihistamines please check with your doctor before you stop the medicine. If the medicine is not stopped before the test we may not be able to perform the test.

Stop these oral antihistamines for 5 days before your appointment:

• Claritin^® (loratadine)
• Allegra^® (fexofenadine)
• Clarinex^® (desloratadine)
• Zyrtec^® (cetirizine)
• Xyzal^® (levoceterizine)

Stop these oral antihistmanines for 3 days before your appointment:

• Actifed^®, Dimetapp^® (brompheniramine)
• Atarax^®, Vistaril^® (hydroxyzine)
• Benadryl^® (diphenhydramine)
• Chlortrimeton^® (chlorpheniramine)
• Phenergan^® (promethazine)
• Tavist^®, Antihist^® (clemastine)
• Astelin^®, Astepro^®, Dymista^® (nasal sprays)
• Actifed^®, Aller-Chlor^®, Bromfed^®, Drixoral^®, Dura-tab^®, Novafed-A^®, ine-D^®, Trinalin^® (Combination medicines)

If you are taking an antihistamine that is not listed, ask your doctor.

Some antidepressants can also act as an antihistamine. Let your doctor know if you are on any antidepressants before the food challenge. Do not stop the antidepressant without discussing it with your doctor.

Stop these medicines the night before your appointment:

• Singulair^® (montelukast)
• Accolate^® (zafirlukast)

Stop these medicines the morning of your appointment:

• Zyflo^® (zileuton)
• Tagamet^® (cimetadine)
• Zantac^® (ranitidine)
• Pepcid^® (famotidine)
• Axid^® (nizatidine)

Continue to take all other medicines as you usually do.

You will begin the food challenge by eating a small amount of the suspected food. If the first dose is tolerated you will be given gradually increasing amounts of the food every 15 to 30 minutes until a normal meal-sized portion is eaten or the challenge is stopped because of symptoms or a reaction. You will be monitored closely during the food challenge by the nursing staff. Your doctor will be available to provide evaluation or treatment in case of any symptoms. 

Once the food challenge is done your doctor will discuss the results with you, answer your questions, and make recommendations.

A single food challenge usually takes from 3-6 hours, but can take longer if you have a reaction. You may want to plan to allow the entire day for the food challenge. 

Talk to your doctor before coming in. We may have you bring specific items, others may provide the food. Discuss your child’s food preferences. For infants, younger children or picky eaters, you may need to have several food options ready to minimize the possibility of food refusal for a picky eater. For example, soy may be tested as edamame, tofu, soy ice cream or soy milk.

For children, bring favorite serving dishes and utensils, and distractions such as toys, books, or homework.

is the most common and is relatively painless. A very small amount of certain allergens is put into your skin by making a small indentation or “prick” on the surface of your skin.

If you have allergies, just a little swelling that looks and feels like a mosquito bite will occur where the allergen(s) to which you are allergic was introduced. If you are allergic to ragweed pollen but not to cats, only the ragweed allergen will cause a little swelling or itching. The spot where the cat allergen was applied will remain normal.

You don’t have to wait long to find out what is triggering your allergies. Reactions occur within about 20 minutes. And you generally won’t have any other symptoms besides the small hives where the tests were done, which go away within 30 minutes. If your prick skin tests are negative but your physician still suspects you might have allergies, more sensitive “intradermal” tests may be used in which a small amount of allergen is injected within the skin.

When you have intradermal skin testing done, a small amount of each thing you may be allergic to (allergen) is injected under the skin. If you are allergic to an allergen, you will get a bump and redness where the allergen was injected.

After a short time, each skin test reaction is measured for swelling and redness. A large enough skin reaction is a positive skin test. This means an allergy may exist to the allergen placed at that site.

Your doctor will compare your skin test results with your history of symptoms.

Please follow these directions when getting ready for this test. Check with your/your child’s doctor before you stop the medicine. All antihistamines will effect the results of some of these tests and need to be stopped before the testing is done. If the medicine is not stopped before the test we will not be able to complete the test.

• Stop these oral antihistamines for 5 days before your appointment:
  • Allegra® (Fexofenadine)
  • Atarax®, Vistaril® (Hydroxyzine)
  • Zyrtec® (Cetirizine)
• Stop these oral antihistmanines for 3-4 days before your appointment:
  • Actifed®, Dimetapp® (Brompheniramine)
  • Benadryl® (Diphenhydramine)
  • Chlortrimeton® (Chlorpheniramine)
  • Claritin® (Loratadine)
  • Clarinex® (Desloratadine)
  • Phenergan® (Promethazine)
  • Tavist®, Antihist® (Clemastine)
  • Actifed®, Aller-Chlor®, Bromfed®, Drixoral®, Dura-tab®, Novafed-A®, Ornade®, Poly-Histine-D®,Trinalin® (Combination medicines)
• If you are taking an oral antihistamine that is not listed stop the medicine for 3-4 days before your appointment. If you are not sure if the medicine you are taking is an antihistamine, ask your doctor.
• Stop these medications the night before your appointment:
  • Singulair® (montelukast)
  • Accolate® (zafirlukast)
• Stop these medications the morning of your appointment:
  • Zyflo® (zileuton)
  • Tagamet® (cimetadine)
  • Zantac® (ranitidine)
  • Pepcid® (famotidine)
  • Axid® (nizatidine)
• Sometimes antidepressants can also act as an antihistamine. Let your doctor know if you are on any antidepressants before your skin testing.

Continue to take all your other medicine as you usually do.

Please follow these directions when getting ready for this test. Check with your/your child’s doctor before you stop the medicine. All antihistamines will effect the results of some of these tests and need to be stopped before the testing is done. If the medicine is not stopped before the test we will not be able to complete the test.

• Stop these oral antihistamines for 5 days before your appointment:
  • Allegra® (Fexofenadine)
  • Atarax®, Vistaril® (Hydroxyzine)
  • Zyrtec® (Cetirizine)
• Stop these oral antihistmanines for 3-4 days before your appointment:
  • Actifed®, Dimetapp® (Brompheniramine)
  • Benadryl® (Diphenhydramine)
  • Chlortrimeton® (Chlorpheniramine)
  • Claritin® (Loratadine)
  • Clarinex® (Desloratadine)
  • Phenergan® (Promethazine)
  • Tavist®, Antihist® (Clemastine)
  • Actifed®, Aller-Chlor®, Bromfed®, Drixoral®, Dura-tab®, Novafed-A®, Ornade®, Poly-Histine-D®,Trinalin® (Combination medicines)
• If you are taking an oral antihistamine that is not listed stop the medicine for 3-4 days before your appointment. If you are not sure if the medicine you are taking is an antihistamine, ask your doctor.
• Stop these medications the night before your appointment:
  • Singulair® (montelukast)
  • Accolate® (zafirlukast)
• Stop these medications the morning of your appointment:
  • Zyflo® (zileuton)
  • Tagamet® (cimetadine)
  • Zantac® (ranitidine)
  • Pepcid® (famotidine)
  • Axid® (nizatidine)
• Sometimes antidepressants can also act as an antihistamine. Let your doctor know if you are on any antidepressants before your skin testing.

Continue to take all your other medicine as you usually do.

Intradermal skin testing takes about 20 minutes to complete.

Depending upon the findings of the initial evaluation, the following tests may be necessary:

• Allergy skin testing may be performed to check for presence of allergic antibodies to selected drug allergens. Patch skin testing can also be performed.

• Blood testing is occasionally indicated.

• Sometimes a challenge to the suspected drug is necessary to confirm the diagnosis. If indicated, drug challenges are coordinated with safety as the highest priority.

The best way to treat drug allergy is to avoid the medication and other medications in its class, since there is no cure for allergy. Antihistamines and steroids can be used to alleviate symptoms, but once a drug allergy is determined, the medication should be avoided.

In very rare cases, it may be required to ‘treat through’ a medication allergy. That is, the drug may be required despite the reaction. This can be dangerous and is only used as a last resort. A person may be pre-treated with steroids or antihistamines in such cases. In addition, if a person requires a drug/medication to which he/she is allergic, drug desensitization can be performed in a hospital setting.

A person is given gradually increasing doses of the medication either by mouth or by IV under constant monitoring until they can tolerate a full dose. It is very important to remember that desensitization works only for that particular course of the medicine, so if it is discontinued, the person once again becomes allergic and needs to be desensitized each time the medicine is administered.