What Is Food OIT and Sustained Unresponsiveness?

This is a great question! As many of you reading this likely know, oral immunotherapy (OIT) is a desensitization process for treatment of peanut and other food allergies. You can think of oral desensitization as what Dread Pirate Roberts (Westley) did with iocane powder- a colorless, odorless, and deadly poison from Australia.

Westley spent two years building up a tolerance to iocaine powder by ingesting increasing amounts of it, so it would not hurt him. He uses this protection to defeat Vizzini in their battle of wits!


Early OIT for peanut has been shown to be ~98% effective for infant to toddler aged kids while only 20-30% of kids otherwise outgrow peanut allergy. A multicenter study published by Jones et al., in Lancet in January 2022 looked at 146 kids 1-4 years-old who either received a maintenance OIT peanut dose equivalent to ~ 8 peanuts daily (96 kids) or placebo (50 kids).

After more than 2 1/2 year of OIT, 68 of the 96 (71%) on OIT could tolerate a challenge equivalent to about 20 peanuts compared to 1 of the patients (2%) on placebo. So, even if kids could not tolerate the ~20 peanut equivalent challenge, they were still able to tolerate ~8 peanut equivalent once daily.


The primary goal of OIT is to reduce the risk of an anaphylactic (life threatening) reaction due to an accidental food exposure, but the odds are excellent there is even greater benefit! Twenty-one percent of kids in the study who had reached a maintenance peanut OIT dose were able to tolerate about 20 peanuts even after discontinuing OIT for over 6 months. They had achieved SUSTAINED UNRESPONSIVENESS (SU) or what can be thought of as REMISSION from their peanut allergy!

The percentage who achieve remission seems to go up significantly when the SU challenge is done after 4 weeks of avoiding the food (usually after a few years of OIT). In a study by Vickery et al., published in The Journal of Allergy & Clinical Immunology in January 2017, the success rate for achieving remission for children 9-36 months of age was over 90% for those who completed the protocol for peanut. Once someone achieves remission by passing a SU challenge, then they should no longer need to have access to epinephrine for that particular food!


Together, these studies show that starting peanut OIT before 4 years of age increases the likelihood of achieving both desensitization AND remission, suggesting a window of opportunity at a young age for treatment of peanut allergy!

That is not to say that older kids cannot be successfully desensitized. In fact, our first patient was desensitized at 9 years of age, and is now nearly 16 years-old and doing very well! We have also had teenagers and adults successfully achieve a maintenance dose of OIT.

While these studies focus on peanut, the same outcomes likely hold true when using OIT to treat other food allergies, such as milk/dairy, eggs, tree nuts, soy, and sesame. Our team is constantly working hard to provide the safest and most effective treatment opportunities for our food allergy patients! If you are interested in learning more about OIT, schedule a visit with one of our providers. You can do so here: https://aafacenters.com/contact/


You can also read more about OIT on our Food Allergy Center page.


We also recommend you read or see the Princess Bride if you haven’t already!

Welcome patients of Dr. Esswein to Allergy, Asthma & Food Allergy Centers!

Dear Dr. Esswein Patients,

We are delighted to welcome you to our practice! While we did not anticipate this particularly trying time, we aim to make your transition as smooth as possible. 

If you are on allergy injections, we should now have your vials. Once we have entered your vials into our electronic system and have you registered in the practice, we will call to let you know that you can come for your injections.  Please wait for this call before you come to our office, but in the meantime, please download the new patient paperwork from this page and allergy shot treatment consent and financial consent. Email the completed new patient paperwork, consent forms, copies of the front and back of your insurance card, and driver’s license to info@aascare.com. Please include in the subject line “transferring Dr. Esswein patient”. If you have not received a phone call in the next 1-2 weeks, please call us. Please also schedule a telemedicine visit at your earliest convenience in order to become further established in our practice. You will need to have that visit before we can refill medications and answer medical questions. The first telemedicine visit will be with Dr. Esswein or one of our advanced practice providers (Lauren Davis, PA-C, Laura Kahle, PA-C, or Dani Loftus FNP-BC) so we can get you established as soon as possible. You can read more about telemedicine visits here.

  • Allergy injections are administered:
    •  8:30AM – 4:30PM Mon-Thur
    •  8:30AM – 2:30PM Fri
    • You will notice we have shot hours on Tue evenings (not currently offered during the COVID-19 pandemic) and Sat mornings. We ask that you kindly avoid these times until further notice, as they are typically our busiest times with the longest wait periods. 
  • We follow the guidelines from our professional allergy societies  that all allergy injection patients will need to wait in the office for 30 minutes after their injections.
  • During this time of concern for COVID-19, we will not escalate your dose. This is to help minimize the risk of an adverse reaction, particularly as we are now in the spring season. We will also allow you an extra week “grace period” where you will not be considered late. 

If you are on a biologic for asthma or hives (ex. Xolair, Fasenra, Nucala, Cinqair, or Dupixent), please call to schedule a telemedicine visit at your earliest convenience. This will allow us to get you registered in the practice and enable us to go through the necessary prior authorization process to obtain your medications. When you are due for your injection(s), and we have verified that we have your medication, we will schedule an in person visit in the office. Please note that our policy is that you will need an office visit for each biologic injection administered in the office. New Patient paperwork is available on this page and information on telemedicine visits is available here. Email the completed new patient paperwork, consent forms, copies of the front and back of your insurance card, and driver’s license to info@aascare.com. Please include in the subject line “transferring Dr. Esswein patient”.

For all other patients, we request that you please schedule a telemedicine visit at your earliest convenience to become established in our practice. We will need to see you for the telemedicine visit in order to refill medications or answer any medical questions. This is also an excellent time to do an annual visit. We can provide updated food allergy and asthma action plans at the time of the visit if needed. New Patient paperwork is available on this page and information on telemedicine visits is available here. Email the completed new patient paperwork, consent forms, copies of the front and back of your insurance card, and driver’s license to info@aascare.com. Please include in the subject line “transferring Dr. Esswein patient”.

We recommend that you follow us on Facebook. We will be posting practice updates, particularly as we do our best to navigate the challenges posed by COVID-19. 

It is our pleasure to play a role in keeping you well. We look forward to meeting you!

FDA Approves Palforzia for Treatment of Peanut Allergy

Our providers and staff at Allergy, Asthma & Food Allergy Centers are excited to learn of the FDA’s decision to approve Palforzia as the first “drug” for the treatment of peanut allergy, as this signifies greater acceptance of oral immunotherapy (OIT) as mainstream treatment for life-threatening food allergies.

Based on our 3+ years of direct experience treating peanut-allergic patients with OIT and the collective 10+ years of experience from other private practice OIT centers across the country, the safety and efficacy data of the Palforzia “drug” is comparable to our method of using readily available sources of peanut protein to perform oral desensitization. This is where the similarities end.

First, the highest treatment dose of Palforzia is 300 mg of peanut protein, about the equivalent of 1 whole peanut or 1/4 teaspoon of peanut butter. Thus, the primary goal of this drug is to raise the threshold of having an allergic reaction to an accidental ingestion of peanut protein (“bite-proof”), which in itself can be a remarkable achievement for peanut allergy sufferers. On the other hand, our protocol is designed to allow patients to reach a daily maintenance dose of 2000 mg (2 grams) of peanut protein, equal to 8 whole peanuts or 2 teaspoons of peanut butter. Furthermore, this maintenance dose actually allows them to safely ingest at least 6000 mg (6 grams) of peanut protein, equal to 24 whole peanuts or 2 tablespoons of peanut butter. This provides the majority of our patients the freedom to eat any amount of peanut protein they wish. That being said, each patient and family may have a different safety goal in mind, and our OIT protocol also provides the flexibility to achieve this goal.

Second, Palforzia is only approved for the treatment of peanut-allergic patients between the ages of 4 and 17 years. Our OIT program has no age limits. In fact, some of our most impressive outcomes have been seen in our infants with peanut allergy!

Additionally, there is no OIT “drug” close to FDA approval for the treatment of food allergies other than peanut. We currently have patients undergoing OIT for egg, milk, tree nuts, wheat, soy and sesame.

Finally, the company that makes Palforzia has set the annual price for their “drug” at $10,680 (or $890 per month) with no guarantee of health insurance coverage at this point. Our current OIT patients/families will spend on average less than $200 in total for peanut flour capsules supplied by a local compounding pharmacy. Beyond that, they are using store-bought roasted peanuts or peanut butter. Palforzia may simply not be a cost-effective option, especially for the level of protection it will provide for those with peanut allergy.

For those of you interested in learning more about all treatment options for peanut allergy, please call our office to schedule an appointment with one of our board-certified allergists. As always, Drs. Borts, Warrier and Vitale are accepting new patients in our main (Sunset Hills, MO) office. Furthermore, Dr. Palis primarily sees new patients in our Swansea, IL office, only 15 miles east of downtown St. Louis.

Peanut oral immunotherapy (OIT)- one step closer to FDA approval

Many people or families affected by peanut allergy are likely aware that on Friday, September 13, 2019, an FDA advisory panel voted 7 to 2 to recommend Aimmune’s peanut oral immunotherapy (OIT) product originally identified as AR101 (now with the brand name Palforzia). Here is a link to a New York Times article regarding this. While the vote is non-binding, the FDA usually follows their advisory panel’s recommendation. If approved, Palforzia will be indicated as a treatment to reduce the incidence and severity of allergic reactions after accidental exposure to peanut in those aged 4 to 17 years of age with a confirmed diagnosis of peanut allergy. 

The data reviewed by the panel showed a 9.1% risk of anaphylaxis with Palforzia compared to 3.5% risk for placebo with dose escalations (updosing). There was an 8.7% risk of anaphylaxis with Palforzia compared to 1.7% risk for placebo while on maintenance dosing. Epinephrine use during dose escalations was 10.4% for Palforzia compared to 4.8% for placebo, and 7.7% for Palforzia compared to 3.4% for placebo while in the maintenance phase. 

Now let’s review the projected cost for the FDA approved product. Analysts have estimated the cost for Palforzia to be $4,200 a year for an individual patient. This is the cost of the standardized peanut flour alone and does not take into account the cost for office visits. Currently, the cost for peanut allergic patients going through our customized OIT program at Allergy, Asthma & Food Allergy Centers (AAFAC) is approximately $2/capsule, which would total $730/year IF TAKING IT DAILY FOR THE ENTIRE YEAR. As our peanut OIT patients know, if things are going smoothly, after approximately 16 weeks (112 day), our patients have transitioned to actual peanuts (sometimes this transition occurs sooner) for a cost of ~$224, which is obviously much, much lower than the cost of the “drug” Palforzia. Additionally, there is no recurring annual cost since patients are consuming regular store bought peanut products for their maintenance doses.  Some other practices just starting OIT this summer (2019) in the greater St. Louis area are taking another approach. Instead of billing insurance, they offer peanut OIT on a cash basis. At Allergy, Asthma & Food Allergy Centers, the typical expense to reach a maintenance dose is less than $2500, though this depends on an individual’s insurance plan (insurance companies set the amount for office visit copays and deductibles), so the out of pocket expenses could be significantly lower. Our practice goal is to ensure as much access to OIT as we can by making it as affordable as reasonably possible for our community. We know what it is like to have food allergies in our own families- the fear, the insecurity, the near constant worry when our kids with food allergies are in an environment we cannot control- which is the main reason we pioneered OIT in the St. Louis area. We have now expanded to Illinois to give even more patients and families suffering with food allergies additional options for treatment. Our office there is located at 510 Fullerton Road, Swansea, IL 62226.

So what exactly is the “drug” Palforzia (AR101)? While the FDA classifies it as a drug, it is basically standardized peanut flour in a capsule. The standardization is necessary for clinical trials and FDA approval, but there is no evidence that using Palforzia is superior to using regular peanut flour that is commercially available for OIT (as practices across the country have been doing for more than a decade). Nevertheless, we at Allergy, Asthma & Food Allergy Centers are very excited that at least some form of OIT will soon achieve FDA approval. This is a big step in giving more people a choice when it comes to managing peanut allergy, though as mentioned above, people in the greater St. Louis region have had the option of OIT through our practice since 2016, and we currently have patients going through OIT not only for peanut but also for cow’s milk/dairy, egg, wheat, soy, sesame, and tree nuts.

Oral immunotherapy is not for the faint of heart. It takes a lot of dedication and courage from patients and their families. While there are real risks, including both anaphylaxis, eosinophilic esophagitis, and lack of tolerability due to gastrointestinal issues for some patients, some of the concerns regarding anaphylaxis with OIT have been a bit sensationalized. The risk of having a serious reaction when purposely exposed to an allergen is of course higher than when trying to just avoid the allergen, JUST AS IT IS WITH ALLERGY SHOTS for seasonal/environmental allergens. However, both with allergy shots and with OIT, treatment is administered in a controlled fashion, so individuals know exactly what triggered the reaction and how much they consumed compared to accidental exposures to a food allergy. Many people have died from accidental exposures, but there are no known deaths in the U.S. associated with OIT. In fact, when a life threatening reaction occurs with OIT, there is usually an associated underlying circumstance (illness, exercise, hot showers, etc) that led to the reaction.

Going back to the example of allergy shots, you do not hear investigators, the press, or other individuals saying that allergy shots should not be administered due to the increased risk of anaphylaxis. There are generally risks with any form of medical treatment, but the potential improvement in the quality of life for an individual and family after either allergy shots (also done at AAFAC) or OIT can be HUGE, even LIFE CHANGING, as people who have been through these treatments in our office (and other places) can readily attest. While some investigators suggest that there is no evidence of an improved quality of life with OIT, we strongly disagree and address it in a previous post https://aascare.com/food-oit-and-quality-of-life/

Food allergy and OIT have become somewhat of a sub-specialty for allergists, and not all allergy offices will be equipped or even have an interest in offering this treatment. There are reasons for this, and this blog post from OIT 101 addresses this issue.

We at Allergy, Asthma & Food Allergy Centers look forward to continuing to partner with our patients and their families to improve health outcomes for environmental allergies, asthma, and food allergies! Thank-you for your trust and dedication!


Food OIT and Quality of Life

Recently, Chu et al published their analysis of randomized controlled trials of oral immunotherapy (OIT) for peanut in The Lancet. Their conclusions are worth reviewing, but it should also be made clear that at least one of the authors has long been opposed to OIT being available to the broader public outside of academic studies. You can read some of our thoughts on OIT and why academics do not approve of this treatment in of our older posts here- https://aascare.com/treatment-for-food-allergies-what-is-oral-immunotherapy-or-oit/

The recent analysis looked at 12 trials of 1024 patients who have gone through rigid controlled protocols for OIT and does not take into account the much, much larger number of patients who have successfully completed OIT through private practice groups such as The Food Allergy Center of St. Louis (division of Allergy, Asthma & Food Allergy Centers of St. Louis). To put this in perspective, our practice alone has over 90 patients on a maintenance dose of peanut OIT with over 80 active patients in the process of going through our customized peanut OIT program (more than 100 active patients if looking at all OIT foods), and THOUSANDS of individuals throughout the country have successfully completed OIT through private practice allergists. You can see the published data from the experience of private practice OIT allergists here- Private Practice OIT Experience.

The recent analysis determined that individuals treated with OIT have a higher risk of having food allergic reactions while actively going through OIT compared to those who just continue to strictly avoid the food allergen. This is not surprising, of course, since when someone goes through OIT, they are ingesting the food allergen and the main risk of OIT is having a reaction to that food.

The most interesting finding in the Lancet article is that the parents’ or individuals’ quality of life was not improved with OIT. While that may have been true for the people in those studies (possible reasons for this discussed below), at the Food Allergy Center of St. Louis, we know that OIT has had an incredible positive impact for patients and families with food allergies as well as ourselves. So how could the academic researchers find that OIT did not have an impact on people’s quality of life?

Here are some possible explanations.

  • Patient selection- The limited number of patients selected to go through OIT in academic studies may be different than people going through OIT in private practice. People may have different reasons to participate in a study versus going through active OIT treatment for themselves or their children. The OIT families in our practice are incredibly motivated to do what is best for their child and/or themselves. They are dedicated, cautious, and often very knowledgeable about OIT before they even come to see us.


  • People treated through academic OIT studies have to follow RIGID protocols that ARE NOT CUSTOMIZED to each individual. If someone going through an academic study protocol is having an adverse event (vomiting, abdominal pain, allergic reactions, etc), there are strict limitations on altering the study protocol. This is VERY different from our ability to tailor an OIT program for individuals with food allergies, especially when there are problems. This is also likely why the success rate of OIT from academic studies and from companies that are attempting to produce FDA approved OIT products are much lower  (<70% success) compared to our success rate (>85%). Our priorities are SAFETY and SUCCESS!


  • Approaches to OIT have changed since the initial OIT studies were done. So of course, if you include studies from over a decade ago, patients’ experiences from that time are likely very different than those going through OIT now, especially those going through OIT in private practice groups. We understand how to adapt and adjust therapy when there are any issues. We are also continually evaluating and re-evaluating our protocols to both standardize them while maintaining flexibility to customize them for each individual person in our OIT program.


We certainly appreciate the incredible pioneering work and time that academic researchers have invested into studying OIT. Their studies clearly show that OIT is very successful, which is why we and many of our colleagues throughout the world have dedicated themselves to bringing this life altering treatment option to those with food allergies.

Food Intolerances

There has been increasing concern regarding food intolerances over the past several years, and people are often confused regarding the difference between a food intolerance and a food allergy. Food allergies (especially the immediate type of food allergies of which most people are aware) can cause life-threatening reactions (anaphylaxis) while food intolerances are not life threatening. There are no standardized tests for food intolerances, and while companies may offer testing for food intolerances, no one actually knows what the testing means. These tests measure “IgG” antibody to foods and do not provide information about food allergies. Testing for “IgE” antibody to foods does provide information regarding food allergies.  With food allergy tests (as with most tests) there can be false positives, so these tests should never be done indiscriminately and should only be done under the care of an allergy specialist. In fact, avoiding a food that someone tolerates without any symptoms based on a positive “IgE” test alone can actually lead to the development of life-threatening food allergies, so allergists strongly advise against random food allergy testing. Since there are no standardized tests for food intolerances, and since most tests for food intolerances show many positive results that do not correlate with a person’s symptoms, the best approach for most individuals is to keep a food and symptom diary to help them determine if a food intolerance (again, not a food allergy) is triggering their symptoms.  Most patients who are healthy and have no symptoms will have IgG antibodies to one or more foods.  Our practice, Allergy, Asthma & Food Allergy Centers of St. Louis, has a very, very strong focus on FOOD ALLERGY but not food intolerances. When patients come to see us about food intolerances, we generally advise against any form of allergy testing.


Please follow this link to watch Dr. Vitale on the news from 2/27/19 discussing food intolerance.

Early Introduction of Peanut

Allergists have suspected for years that early introduction of foods likely decreases the development of food allergies. The LEAP (Learning Early About Peanut Allergy) study published in the New England Journal of Medicine in February 2015, definitively showed that early introduction and regular consumption of peanut (approximately 2 teaspoons of peanut butter 3 days per week) dramatically decreases the risk of developing peanut allergy by about 80%. Since the study was published, new guidelines were also released with the following recommendations:

  1. Children at the highest risk of developing peanut allergythose with severe eczema (atopic dermatitis) and/or egg allergy should have some form of testing to evaluate for the possible presence of peanut allergy. If testing is negative, home introduction or a supervised feeding can be done, and if the child tolerates peanut, they should regularly consume approximately 2 teaspoons of peanut butter at least three days per week. This process should start ideally between 4-6 months of age. If testing is positive, depending on the testing results and the comfort of the specialist, and office based food challenge to peanut may be done to determine if the infant is allergic before introduction at home is considered.
  2. Children in the moderate risk groupthose with mild to moderate eczema and no egg allergy should start consuming peanut (about 2 teaspoons) three days per week starting around 6 months of age. These children do not necessarily need testing before peanut is introduced, which can be done at home.
  3. Children at low risk for peanut allergy- those without signs of eczema and without egg allergy can start consuming peanut when age appropriate and according to family and cultural preferences.

While formal recommendation #3 does not stress early introduction, it is important to note that there is no real downside to early introduction, and delaying introduction even in those without eczema or egg allergy could potentially lead to an increase in developing peanut allergy compared to those who introduce early.

A question parents often have is how peanut can be introduced at home. The video below features Dr. Ruchi Gupta, one of the leading experts in food allergy, discussing home introduction of peanut. We hope you find this helpful!




If your infant or toddler is found to be allergic to peanut, do not despair. There is good recent evidence that early oral immunotherapy (OIT)/desensitization to peanut has very good outcomes (over 90% success rate when done correctly and carefully) and is safe. If you would like more information on OIT, see our Food Allergy Center of St. Louis page.

EpiPen and Mylan Generic Epinephrine Autoinjector Expiration Dates Extended for Some Lots.

Extended Use Dates Provided by Pfizer

Extended use dates to assist with EpiPen intermittent supply interruptions

[August 21, 2018] Due to the intermittent supply interruptions of EpiPen, FDA is alerting health care professionals and patients of updated dates through which some EpiPens and the authorized generic version, manufactured by Meridian Medical Technologies, a Pfizer company, may be used beyond the manufacturer’s labeled expiration date. To help ensure patient safety, these products should have been — and should continue to be — stored as labeled.

Based on stability data provided by Pfizer and reviewed by FDA, the following extended use dates are supported for specific batches indicated in the tables below. Patients that have the batch numbers below will be able to use them through the corresponding new use dates to help with supply. As data become available, this list can continue to expand.

FDA is not requiring or recommending that the identified batches in the following tables be relabeled with their new use dates. However, if replacement product becomes available during the extension period, then the agency expects the lots in these tables will be replaced and properly disposed of as soon as possible.

Please see the recent FDA in Brief for more information, and contact CDER Drug Shortage Staff at drugshortages@fda.hhs.gov with questions regarding these tables.

Epinephrine Injection, USP 0.3 mg Auto-Injectors
NDC 49502-102-02 appears on the box
NDC 49502-102-01 appears on the individual device within the box

BatchManufacturer’s Original
Expiration Date
New Expiration Date
(beyond manufacturer’s
original expiry date)

EpiPen® (epinephrine injection, USP) 0.3 mg Auto-Injectors
NDC 49502-500-02 appears on the box
NDC 49502-500-01 appears on the individual device within the box

BatchManufacturer’s Original
Expiration Date
New Expiration Date
(beyond manufacturer’s
original expiry date)