Foods & Medications to Avoid Before Allergy Testing (2024)

Navigating Allergy Testing

In this updated post, I’m excited to provide you with the 2024 edition of my Quick Reference Guide on Foods & Medications To Avoid Before Allergy Testing. Perfect timing for us, as Lily, now 14, is gearing up for a skin patch test tomorrow. (Late last year, she completed a skin-prick test). Alongside valuable insights gained from a decade of Lily’s allergy testing experiences, I’ve further addressed common questions like the importance of avoiding caffeine before allergy tests. Additionally, I’ve updated all medication-related info, ensuring that this guide is not only comprehensive, but also presented in a more reader-friendly format.Let’s dive into the nuances of allergy testing prep and make informed choices together. 

Why Is Food Allergy Testing Used?

In the world of allergy testing, we often encounter skin prick tests, blood tests, patch tests, and oral food challenges. Mayo Clinic notes that while no test is perfect, these methods play an important role in diagnosing food allergies. So, why do we undergo food allergy testing? It’s a quest to uncover specific allergies or determine if we’ve outgrown any. These tests differentiate between true allergies and sensitivities or intolerances. Remember, the symptoms of food intolerances—nausea, cramping, bloating—are distinct from life-threatening allergic reactions.

Understanding the Difference Between Food Allergies and Intolerances 

Let’s clarify: Food allergy tests address allergies, not intolerances. They might reveal a milk allergy but won’t detect lactose intolerance. Similarly, celiac disease won’t show up, but a wheat allergy might. Understanding these distinctions is crucial as it guides us through the complexity of allergy testing.

Mapping the Path Forward

When a potential allergy is identified, an elimination diet may follow, restricting trigger foods. Subsequently, an oral food challenge, supervised by your doctor, helps reintroduce these foods. This journey, shaped by Lily’s experiences, aims to demystify and simplify food allergy testing for you. Understanding the common food allergy tests is key before stepping into your allergist’s office. These tests are listed below, and each play an important role in understanding the complexities around food allergies.

Common food allergy tests:

1. Skin Prick Test (SPT)
2. Blood Tests (Specific IgE)
3. Patch Test (Atopy Patch Test)
4. Oral Food Challenge Test

Last year, our allergist recommended that Lily do a Skin Prick Test and the Specific IgE Blood Test. This year we are doing a Patch Test, also called  an Atopy Patch Test.

Why More Than One Food Allergy Test Helps Fill In the Blanks

Because food allergies can be complex, you may need to do more than one test or procedure. Sometimes skin tests or blood tests alone aren’t conclusive. Completing multiple tests ensures a better understanding when more answers are needed. While neither skin tests nor blood tests are perfect, the more information, the better. Food allergy testing empowers us to be informed about foods we should avoid. It might even uncover foods we no longer need to steer clear of.

1. Exploring the Skin Prick Test (SPT) 

What is a Skin Prick Test (SPT)?

Skin prick testing, also known as a scratch test or puncture test, confirms many common food allergies. During an SPT for an egg allergy,  a small drop of egg proteins is placed on your skin, followed by a light prick or scratch. A reaction, like redness, swelling or itching, indicates sensitivity. You may see a raised, round area that looks like a hive. This shows up usually within 15 minutes at the test site. Usually, the larger the reaction, the more likely you’re allergic to the allergen. However, a positive test doesn’t guarantee a severe allergic reaction, while a negative test usually suggests no allergy. 

SPT is the preferred testing method for true food allergies. It’s safe for most, even infants, and offers immediate results during a regular clinic visit. However, patients with sensitive skin, like those with atopic dermatitis, might encounter false positive results. 

Foods and Drinks To To Avoid Before Allergy Testing With SPTs: Caffeine

Preparing for a Skin Prick Test involves conscious choices about foods and medications. Let’s dive into what you should avoid before this important allergy exam.

In the lead-up to a Skin Prick Test, you should avoid any food or drinks with caffeine, like coffee or chocolate, for at least 24 hours before testing. Why? These products can influence physiological reactions like heart rate, blood pressure, and other vital signs. Caffeine’s impact on symptoms and immune system response can mask important information. Additionally, it has the potential to elevate anxiety levels, introducing an additional variable that could affect the test’s accuracy.

Medications to Avoid Before Allergy Testing With SPTs

Understanding the impact of medications on Skin Prick Tests (SPTs) is crucial to ensure accurate results. Let’s dive into the medications you should be mindful of before your food allergy test.

Creating a Medication Checklist Before SPTs

Before scheduling a skin test, create a comprehensive list of prescription and over-the-counter medications you’re taking.  These may include antihistamines, tricyclic antidepressants, certain heartburn medications, and the asthma medication, Xolair.  Some of these medications have the potential to suppress allergic reactions, impacting the accuracy of skin testing.

Precision in Allergy Testing: Holding Medications Before Allergy Testing

For optimal accuracy, your doctor will request you refrain from medications that interfere with testing. Discuss the timeline for discontinuation with your doctor to achieve the most accurate results prior to your test.

Guidance on Over-The Counter Antihistamines Before Allergy Testing With SPTs

If you rely on over-the counter antihistamines for relieving allergic rhinitis symptoms, such as a runny nose, consult your doctor on how and when to discontinue them. These medications can significantly influence the results of your skin test.

Navigating Antidepressant and Cardiac Medications

Discuss discontinuation plans with your doctor if you’re taking an antidepressant, anticipating potential withdrawal symptoms. If you’re on a monoamine oxidase inhibitor for depression or a beta-blocker for a heart condition, talk to your doctor, especially if epinephrine might be necessary for an allergic reaction.

To see a list of medications that you should discuss with your doctor, click here

2. Decoding the Specific IgE Blood Test Before Your Appointment

What is a Specific IgE Test?

Understanding the Specific IgE blood test is crucial as it checks for antibodies known as immunoglobulin E (IgE) in your blood, providing insights into allergic responses. The Specific IgE blood test examines immunoglobulin E (IgE) antibodies in your blood, produced by your immune system in response to allergens. Even harmless substances can trigger an immune response, leading to the production of IgE antibodies. This blood test is preferred for its simplicity, often detecting various allergens with a single draw.

Navigating the Imperfections of Specific IgE Blood Testing

Commonly known as RAST or ImmunoCAP testing, this blood test, while valuable, isn’t perfect. Like many diagnostic tests, it has a notable rate of false positive results, exceeding half of the results. In other words, testing positive doesn’t always correlate with experiencing allergy symptoms when you eat the identified food.

Ideal Candidates and Circumstances for Blood Tests

Blood tests are ideal for patients with sensitive skin conditions like eczema, those on  medications like antihistamines that may interfere with skin prick tests, or young children unable to undergo skin allergy tests.

Foods to Avoid Before Allergy Testing With Specific IgE Tests: 

Unlike some allergy tests, there’s generally no need to alter your diet before a Specific IgE Blood Test. However, in specific cases, healthcare providers might recommend fasting before the test. Confirming these details with your doctor ensures a smooth testing process.

Medications to Avoid Before Allergy Testing With Specific IgE Tests

Before your Specific IgE lab test, check with your doctor’s office. In our experience, we confirmed no fasting, no dietary restrictions, and no need to stop medications, including Zyrtec, before our blood test.  Confirming these specifics with your HCP ensures accurate and reliable results. 

3. Preparing for the Oral Food Challenge (OFC)

What is an Oral Food Challenge (OFC) Test?

Exploring the gold standard in diagnosing food allergies, the Oral Food Challenge (OFC) Test offers unparalleled accuracy.  Acknowledged as the most accurate food allergy test, the Oral Food Challenge is often recommended following a skin prick test or blood test. It proves particularly beneficial when you’ve tested positive for a food, but haven’t experienced a reaction, or if improvements are evident in your skin and blood test results.

Navigating the Oral Food Challenge Process

Conducted under the watchful eye of an allergist, this tests unfolds in a doctor’s office, due to the potential for life-threatening reactions or anaphylaxis. The allergist and their expert team carefully feeds you a food, monitor your reaction, and stand ready to provide emergency care if needed. The process can take 3-6 hours under medical supervision, ultimately confirming your allergies and guiding whether continued avoidance of the food is needed.

Foods To Avoid Before Allergy Testing With A Food Challenge Test

In preparation for a Food Challenge Test, you can have a small meal on the day of the challenge, sticking to familiar foods that haven’t triggered allergic reactions previously.  Typically, you will be advised not to eat 1-2 hours before your food challenge.  Specific instructions may vary, so it’s important to consult your doctor regarding any tailored guidelines for your test. Understanding these nuances ensures a smooth and informed experience during the Oral Food Challenge.

4. Decoding the Patch Test for Allergies

What is a Patch Test?

Patch testing is a valuable diagnostic tool for skin inflammation and suspected allergies. It is especially helpful in cases of contact dermatitis or delayed skin reactions, when reactions take several days to manifest post-exposure to an allergen. 

Navigating the Patch Test Procedure

During a patch test, a small amount of allergen is applied to the skin, often on your back, and covered with a bandage. The reaction at the application site is assessed after 48 to 96 hours. This process typically involves exposure to 20 to 30 extracts of substances, with the appearance of a local rash or itchy bump indicating an allergic response. For our patch test this week, we will be testing 150-160 allergens. If the cost of testing is concerning, we were advised that we can call our provider for the total cost to determine how many items the allergist will be testing to. There are 10 allergens on each patch and she will have between 10-15 of the patches placed on her back.

Tailored Approach for Food Allergy Testing with the Patch Test

When conducting the patch test, actual food is used to observe your body’s reaction. The selection of foods is based on  your diet, medical history, and prior skin testing results. Your back is fitted with a tape containing a panel of food extracts, and a follow-up appointment after 48 to 96 hours allows for the removal of the panel and a physical exam to assess your skin’s reaction. 

Besides food allergens, patch testing can encompass a range of common allergens such as latex, medications, fragrances, preservatives, metals, hair dyes and resins. This comprehensive approach aims to pinpoint specific triggers contributing to skin reactions, offering valuable insights for accurate diagnosis and management.

For our Patch Testing, a medical assistant reached out to us prior to our appointment with a few reminders. A notable one was to bring personal care products such as shampoo, conditioner, body wash, hand soaps, lotions, creams, topical prescriptions, oils or anything else that may come into contact with problem areas. They don’t need our laundry soap, fabric softener, or household cleaners. Also, they reminded us to keep the back dry during the week of patch testing. This means no sweating, no swimming, no showers, and very minimal physical activities. They also recommended wearing old clothes during the week of patch testing as some dyes and pen marketing’s may transfer on to clothing.

Foods to Avoid Before Allergy Testing with Skin Patch Tests

Similar to the skin prick test, your doctor may recommend avoiding food or drinks with alcohol, chocolate, coffee, and other caffeine products as they could impact test results. For guidance tailored to you, please consult your doctor to determine specific dietary restrictions. 

Medications to Avoid Before Your Allergy Testing With Skin Patch Tests

In preparation for your Skin Patch Test, you may need to stop taking certain medications, including oral steroids such as prednisone, methotrexate, and cyclosporine, as well as any other immunosuppressive medications. If  you’ve received allergy or cortisone injections, inform your doctor of these details. For our appointment, we were advised not to use oral steroids (prednisone, Medrol DosePack) for 2 weeks prior to and during the time of patch testing. Also, we were reminded to talk to our doctor if we take other medications that suppress your immune system. It was ok to take anti-histamines such as Benadryl, Claritin, or Zyrtec during testing. These can be taken during testing to help with itching. We were also directed to continue all other oral medications during the week of testing unless otherwise instructed by the staff. 

Sun Exposure and Topical Medicines Precautions for Skin Patch Testing

Ensure minimal sun exposure on the area where your patches will be placed ant least a week before your appointment. Additionally, refrain fro using topical medications such as creams and ointments, on your back. Your allergist of food allergy nurse will provide detailed instructions on specific medications to stop and the timing. For us, she advised that sun burns or darkly tanned skin may lead to false negative patch testing. She also advised that topical steroids be avoided on the back for 10 days before testing or during the week of testing. However, it was ok to use topical steroids to other areas during patch testing. Finally, we were asked to avoid applying Vaseline and any lotions to her back 1 week prior to patch testing. 

Summary of Foods and Medicines to Avoid Before Allergy Testing

In summary, for the tests I described above, you should check with your doctor, but this should give you a better idea of what foods to avoid and which medications you might discontinue.  Your doctor will know best so please discuss any questions or concerns you have with them.  For us, here’s what we avoided before allergy testing:

I hope this was helpful information. With these tests, you and your doctor should be able to develop a treatment plan that works for you. Your allergy treatment plan might include medications, immunotherapy, and changes to your diet.

For more information about the oral food challenge and other food allergy testing options, please visit the FARE site for the most up to date resources on food allergies.

Best of luck to you, and thanks again for stopping by!

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Antihistamines to Avoid Before Skin Prick Testing for Food Allergies

Common Oral Prescription and OTC Antihistamines to Discontinue 5-7 Days Before Food Allergy Testing 

Some prescription and over the counter antihistamines are longer acting and often discontinued 5-7 days prior to your Skin Prick Test appointment, however you should check with your doctor:

• Cetirizine / Zyrtec
• Desloratadine / Clarinex
• Fexofenadine / Allegra
• Hydroxyzine / Atarax /Vistaril
• Loratadine/ Claritin /Alavert /or generic
• Levocetirizine / Xyzal

Common Nasal Sprays and Eye Drops

These prescription nasal spray and eye drop antihistamines are often discontinued 5-7 days prior to your Skin Prick Test appointment, however you should check with your doctor:

• Azelastine (Astelin, Astepro, Dymista, Optivar)
• Olapatadine (Pataday, Patanol, Patanase)
• Bepotastine (Bepreve)
• Ketotifen (Zaditor, Alaway) (OTC – no Rx needed)
• Pheniramine (visine A, Naphcon A)
• Epinastine/Elestat (Rx needed)

Common Antihistamines To Discontinue 2-3 Days Before Food Allergy Testing

These antihistamines are often discontinued 2-3 days before your Skin Prick Test appointment, however you should check with your doctor:

• Triplodidine / Actifed
• Most Over-The-Counter/Prescription Combination cough & cold medicines (Tylenol Cold & Sinus, NyQuil, DayQuil, Advil Allergy/Sinus)
• Chlorpheniramine /Chlor-Trimeton
• Cyprohepatdine / Pericactin (appetite stimulant and allergy symptoms)
• Contac Cold + Flu
• Deconamine
• Brompheneramine / Dimetapp
• Diphenhydramine/Benadryl
• Duravent DA (Rx)
• Dura-Tap
• Rantitidine / Zantac
• Famotidine / Pepcid AC, Pepcid Acid Controller
• Nizatidine /Axid
• Doxylamine / Unisom, Sleep Aid, Ultra Sleep
• Pyrilamine / Midol, Pamprin
• Pheniramine /Phernegan (in allergy, cold and sinus preparations including Theraflu)
• Phenergan / Phernergan (Dramamine for motion sickness)
• Promethazine (in prescription cough syrups and anti-nausea)
• Meclizine and dimenhydrinate (Antivert, Bonine Dramamine for motion sickness)

Discuss With Your Doctor Risk of Withdrawal Symptoms

Due to the risk of withdrawal symptoms discontinuation syndrome with some antidepressants, you should talk to your prescribing physician about how to safely taper and not abruptly discontinue these medications and the best way to test for your food allergies.

Antidepressants with antihistamine you should discuss with your psychiatrist or primary care physician before allergy testing with the Skin Prick Test:

• Amitriptyline / Elavil (tricyclic antidepressant)
• Desipramine / Norpramin (tricyclic antidepressant)
• Doxepin / Sinequan (tricycyclic antidepressant)
• Nortriptyline / Pamelor (tricyclic antidepressant)
• Imipramine / Tofranil (tricyclic antidepressant)
• Trazodone / Desyril (SSRI)
• Mirtazapine (Remeron) – (tetracycline antidepressant)
• Protriptyline / Vivactil (tricyclic antidepressant)
• Trimipramine / Surmontil (tricyclic antidepressant)

PLEASE NOTE: Not all allergy medications need to be discontinued prior to testing. You should be able to continue your asthma inhalers or nebulizer treatments (controller and rescue inhalers), montelukast (Singulair), zileuton (Zyflo), theophylline, and oral or topic corticosteroids. However, talk to your doctor about the medications you are currently taking to confirm. 

Medications indicated below do not affect allergy skin tests and MAY BE CONTINUED- however, please confirm with your prescribing physician:

• Allergy medications– pseudoephedrine, phenylephrine decongestants
• Corticosteroids (steroids): Singulair prednisone, prednisolone, methylprednisolone, Medrol Lotemax eyedrops
• Nasal steroid sprays: Flonase, Veramyst, Nasonex, Nasocort, Rhinocort, Omnaris, Qnasl Mucinex, Guiafenesin
• Asthma inhalers: dextromethorphan cough medications (e.g. Delsym)
• Proton pump inhibitors: Aciphex, Dexilant, Omeprazole, Prilosec, Protonix, Prevacid, Nexium

Pat S

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Hello! I'm Pat, and I'm thrilled you've visited our site! Here we honor the many kids facing food allergies fearlessly. Alongside my foodie teen, Lily, who deals with multiple food allergies, we share our exciting food discoveries from travels and everyday life. Join us as we navigate life with food allergies, providing resources and promoting safe dining options. Let's inspire a new generation to make informed choices for our health, well-being, and communities, while having fun along the way!

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