The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 50

62. Is it possible to become tolerant of a trigger again?

Yes, sometimes.

Desensitization is the term for when your body becomes tolerant of something that it previously reacted to. While it usually means becoming tolerant of a medication, it is a general term so many mast cell patients use “desensitization” to mean becoming tolerant of anything they used to react to, including food or environmental triggers.

Traditionally, desensitizing is done by exposing the body to a small amount of a trigger, then a little more at a later time, and so on until the body accepts a reasonable amount. In the regular allergies, in the US, “allergy shots” are used for this. A patient is injected with a tiny amount of an allergen repeatedly until their immune system stays calm when exposed to the trigger.

There are some newer approaches for desensitization that use certain newer medications. In particular, anti-IgE therapy has been very well described for helping to force a patient to tolerate a trigger. Antihistamines and/or corticosteroids can be used to control the level of allergic response.

In some instances, a rapid desensitization procedure can be used to force tolerance. These procedures are performed in a medical setting and may provide tolerance in a matter of days. They are usually used in situations where the benefit of a drug to which the patient reacts outweighs the risk of anaphylaxis, such as patients who need to use a specific chemotherapy drug to treat an aggressive disease.

Importantly, if a patient becomes desensitized to a substance, they must be regularly exposed to that substance in order to continue tolerating it. Sometimes, a patient must be exposed daily in order to not react to the trigger. This is very patient and substance specific.

Mast cell patients are different from typical allergy patients in a lot of ways, many of which we don’t understand. Patients ask from time to time if “allergy shots” or something similar will help them. Mast cell patients who have an IgE allergy to a substance may get some benefit from allergy shots. Specifically, allergy shots are recommended for mastocytosis patients who have allergies to certain insect stings.

But what if they don’t have an IgE allergy? Will gradually increasing the amount of trigger in a series of exposures allow the body to accept it?  I know plenty of mast cell patients who have used allergy shots or oral immunotherapy to improve trigger tolerance. I can’t think of any reason why this wouldn’t help if you could safely increase the exposures.

For mast cell patients, the issue is that reactions can be so serious that desensitization is difficult to achieve. Patients can sometimes overcome this by using IV Benadryl, IV steroids, or a continuous IV epinephrine infusion. Mast cell patients should never attempt to force tolerance to any trigger without receiving advice from a health care provider that understands their specific health situation.

Food allergies are widely recognized as being different from other kinds of allergies. We are learning about food allergies in real time right now. Food allergies are on the rise and now affect huge numbers of people around the world. This means that there’s tons of research on it, which is great. But it means that we still don’t understand them that well. For this reason, desensitization to food is trickier.

There are a few methods commonly used in mast cell patients to manage food reactions. Sometimes a gradually increasing amount of trigger is eaten while the patient is monitored and given medications to manage any reactions, essentially a rapid desensitization for food. I find this approach is taken more commonly with children, largely because it is the recommended procedure for reintroducing triggers to children with FPIES. Sometimes people find that when they are exposed to a trigger for the first time in a while, they tolerate it until a second exposure. In these scenarios, rotation diets can be helpful. Allergy shots or oral immunotherapy for substances found in food are sometimes given. Results vary.

I have talked a lot before about the fact that mast cell reactions are often the cumulative result of things that activate your mast cells. This means that if you do something that activates your mast cells before eating a trigger, your reaction may be worse. In some instances, you may only react if you do something irritating to your mast cells shortly before eating it. This doesn’t just happen to mast cell patients. There are many mentions in literature of allergy patients who only experience anaphylaxis to trigger foods if they have exercised shortly before eating.

This means that if you are able to control the experience of eating triggers, you may have better success. You may do better if you refrain from doing anything irritating to mast cells like exercising, getting too hot, or being in a stressful situation. Food temperature can play a role. Many patients react to foods that are too hot or too cold. How you time medications can help. If you eat in the window of time when your medications are most active, you might find that a trigger is less activating. Solids are harder to digest and cause more histamine release than liquids (even thick liquids) so what form your food takes can matter, too.

Additionally, if you are able to control your disease and inflammation, you may find yourself more tolerant of triggers overall. Patients who find that their symptoms are better controlled should discuss trials with their health care providers to see if they can try exposures to previous triggers.

I can tell you that I have personally had a lot of success with using an anti-IgE medication to help me regain foods I lost. I have one IgE food allergy (chicken egg whites) and have no plans to ever try to consume them without thorough cooking (I’m tolerant of well cooked egg whites.) However, I do have a spectacular amount of food triggers that cause reactions ranging in severity from flushing to anaphylactic shock. My severe food reactions largely resolved when I started anti-IgE injections a few months ago. I eat all kinds of things I used to react badly to. I can eat cookies. I can eat cherry pie. I can eat bread. I try not to push my luck with things that have are loaded in histamine. I will never try alcohol or anything fermented again.

Prior to taking the anti-IgE medication, I had some success with rotation diets in which I ate gradually increasing amounts of a trigger every four days. It didn’t really make the reactions stop but it did make them less severe, enough that I could reintroduce small amounts of some previous triggers into my diet. This happened after I had GI surgery that decreased my overall level of inflammation and mast cell reactivity.

For more detailed reading, please visit these posts:

Food allergy series: FPIES (Part 1)

Food allergy series: FPIES (Part 2)

Food allergy series: Mast cell food reactions and the low histamine diet

Reintroduction of food to a child with SM

The Devil’s Arithmetic

The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 46