mold allergy in the bathroom

Mold Allergy vs Mold Toxicity vs Mold Colonization

Have you ever walked into a moldy room and immediately started having reactions that you thought were a Mold Allergy? 

When you entered those moldy environments, did you have symptoms similar to an asthma attack? Like shortness of breath or chest tightness?  

Or maybe you got burning, itchy, or watery eyes, sneezing, or a runny nose? 

You might have a Mold Allergy if you’ve had any reactions to mold.  

But all reactions to mold aren’t always a true Mold Allergy. 

At Mast Cell 360, when we look at mold related conditions with our clients, we consider all 3 of these possibilities: 

You can have just 1 of these conditions. Or you may have 2. Or you may have all 3. 

So, what is the difference? And how can these be affecting your Mast Cell Activation Syndrome (MCAS)?

Keep reading to find out.  

You’ll also learn more about: 

  • What a true Mold Allergy is 
  • Mold Allergy symptoms 
  • How you can test for a Mold Allergy 
  • Mold Allergy vs Mold Toxicity vs Mold Colonization 
  • How to address a Mold Allergy 
  • How a Mold Allergy may contribute to Mast Cell Activation Syndrome  

Let’s start by understanding what a Mold Allergy is. 

What Is a Mold Allergy? 

It’s important you know that this blog post is for informational and educational purposes. It’s not meant to treat any health condition or to be prescriptive for anyone.  If you have any medical condition, it is critical you work under the care and guidance of a licensed medical provider.  

An allergy is a type of immune response. 

When your body views something as a threat, it takes steps to attack that threat to protect you. 

One way it does this is by producing antibodies in response to the antigen (the threat).  

Antibodies are proteins made by white blood cells. They respond to attack pathogens like bacteria, viruses, and other toxins like mold.  

Antibodies can respond to anything though, not just things that are inherently toxic. 

Anything that stirs up an immune response is an antigen. 

Allergens are a type of antigen.  

Allergens can be things like certain foods or even pet dander. These things aren’t necessarily toxic, but your body views them that way.  

Sending out antibodies is the way your body will fight off these antigens. 

Immunoglobulin E and immunoglobulin G (IgE and IgG) are two types of antibodies that fight off antigens like mold. 

IgE vs IgG Reactions 

Here’s what distinguishes an IgE from an IgE reaction. 

IgE Reactions 

IgE reactions usually show up within a few minutes to a few hours after exposure to the allergen. 

Anaphylactic reactions are one type of IgE reaction. Not all IgE reactions result in anaphylaxis, though. 

However, an anaphylactic reaction is very serious and potentially life-threatening if it does happen. 

Anaphylactic symptoms can include: 

  • Chest tightness 
  • Feeling faint/ fainting 
  • Throat closing 
  • Breathing difficulties including wheezing 
  • Fast heartbeat 
  • Clammy skin 
  • Confusion 
  • Loss of consciousness 

IgE reactions are considered a true allergy. 

Next, let’s look at IgG reactions. 

IgG Reactions 

IgG reactions are considered a sensitivity, not a true allergy. The reaction times for an IgG response can be more delayed.  

The response you experience from an IgG reaction may be milder than an IgE response. 

You can still get uncomfortable symptoms. But IgG responses are not usually life-threatening like an IgE response can be. 

If you have a Mold Allergy, your body will produce these IgE and IgG antibodies to fight off mold when it encounters it. 

In the case of Mold Allergy, if you breathe in or ingest mold spores or the toxins they release (mycotoxins), your immune system launches an attack. 

And in some cases, you don’t even have to be in a moldy environment to be subject to these mycotoxins. See, mold can grow inside the body. This is called Mold Colonization. 

You may have an allergic response to the mold spores in your own body if you have a Mold Allergy. 

Or you may react to the toxins the mold spores release. These are called mycotoxins. 

Having mold inside you is going to make everything much worse if you have a Mold Allergy.  

You’ll read more about Mold Colonization and Mold Toxicity later. And you’ll learn why, if you have these conditions, they may make Mold Allergy symptoms even worse. 

In fact, if you have Mold Colonization or Mold Toxicity, that might be the root of your Mold Allergy and other hypersensitivities. And it might be the root cause of your MCAS, too. 

But more on that in just a bit.  

If you like to learn by watching videos or listening, be sure to catch my presentation on Do you Have a Mold Allergy or Something Else?

Next, though, look at some of the more common Mold Allergy symptoms you might experience. 

My Mold Allergy Symptoms to Mold Exposure 

When I was a kid, my family moved to an old farmhouse. 

Old homes can have leaky roofs, poor window seals, broken gutters, old carpeting, and leaky pipes.  

And many older homes don’t have air conditioning. An air conditioner sucks some of the indoor humidity out of the house.  

Air conditioning doesn’t guarantee you won’t get mold in your home, though. But it can help with moisture, which mold needs to thrive. 

Additionally, we had rainy springs and humid summers. 

All of this can lead to damp areas which are perfect for mold growth. 

Did you know that about 47% of all homes in the USA have water damage? 

Unaddressed water damage can lead to indoor mold. 

And mold can lead to some serious health issues. 

It wasn’t long after we moved into that old farmhouse that my health first started declining. 

I had symptoms that were common allergic reactions. 

The itchy hives were the worst. I would scratch at them until I bled. 

I had a lot of respiratory issues including asthma attacks. 

And I could barely sleep at night. 

My parents took me to an allergist for an allergy test when they realized that I must be dealing with something more than seasonal allergies. 

I was suffering year-round.  

My symptoms never seemed to cease. And I’d often have crying meltdowns from being so miserable. 

What Mold Allergy symptoms have you experienced?  

Mold Allergy Symptoms 

I was truly miserable from my allergic reactions. 

If you’ve had severe allergic reactions, you know how they can interfere with your life. It’s debilitating.  

For me, I started having trouble concentrating. It was hard to focus on anything for very long while I was dealing with chronic headaches, lack of sleep, incessant itching, and constantly blowing my nose. 

I also got bad anxiety.  

When you have allergic reactions, one of the responses your body can have is to release histamine.

And researchers have shown that inflammation associated with histamine release can lead to anxiety. 

I felt like I’d never be “normal” again. 

How Many of These Common Allergic Reactions to Mold Have You Experienced? 

  • Nasal congestion 
  • Stuffy nose 
  • Runny nose 
  • Postnasal drip 
  • Sneezing 
  • Wheezing 
  • Coughing 
  • Asthma symptoms 
  • Chest tightness 
  • Shortness of breath 
  • Headaches 
  • Skin rashes/ Itchy skin 
  • Hives 
  • Watery eyes 

When I got tested at the allergist, it was clear that I was allergic to mold. 

Keep reading to learn more about testing to see if you have a Mold Allergy. 

Then you’ll learn more about the differences between a Mold Allergy vs Mold Toxicity vs Mold Colonization.  

And you’ll see how they may be related to each other and MCAS. 

But next, read more about testing for mold allergies. 

Mold Allergy Testing  

When I had allergy testing done by an allergist, it was painful. 

I was given skin scratch tests. The scratching itself was painful. But the reactions were worse.  

Skin Tests 

My skin scratch tests started with a histamine control.  

My skin was scratched with histamine as a control to be sure an appropriate reaction would happen when other potential allergens are introduced. 

The idea is that if you end up with itchy skin or a raised bump from the histamine, that shows that you are responding appropriately. 

In my case, I’d end up with a 3 to 4-inch welt. So, yes. I was responding! 

Then, they tested for tree pollen, cat dander, dog, dust mites, and several types of molds. 

It turns out that I was reacting to just about everything. My back was one huge welt. 

That made it hard to pinpoint what I was reacting to. And that made more tests necessary. 

But 1 thing was clear. 

The area where mold was introduced was the most swollen. And it itched and burned for a long time after the test. 

I had allergy testing 3 times over the course of my childhood, and each time, I left the doctor feeling worse than when I went in! 

Some doctors still administer skin tests to find what allergies you may have. 

But now, there is another less painful way. And you don’t even need a doctor. 

Blood Tests 

I’d highly recommend blood tests over the skin test, especially if you have Mast Cell Activation Syndrome. 

That’s because allergic reactions can trigger the mast cells.  

Introducing allergens will cause a mast cell response. 

If you are trying to calm down your mast cells, the last thing you want to do is purposefully trigger them! 

Blood tests measure levels of those 2 different antibodies you read about earlier, IgE and IgG. 

IgE can be present in low levels in your body at any time.  

However, higher levels can indicate that your body is reacting to a substance. It could be food, pollen, dander, mold, or even some chemical in your skincare products. 

Related Article: Safe Skincare for those with MCAS and Histamine Intolerance 

Here’s what you should know about blood tests. 

Home Testing 

Nowadays, you don’t even have to go to your doctor for an allergy test. 

IgE Testing 

You can look for elevated levels of IgE or IgG with a test like those from Ulta Lab Tests. You’ll remember that these are the major antibodies to antigens like mold. 

The Ulta Lab test is a blood test. When you get your Ulta Lab test requisition, you can go to a Quest Lab facility to get your blood drawn. Or you can use an in-home phlebotomist (someone trained and licensed to draw blood). 

If your total IgE or IgG is elevated, you’ll know that your body is reacting to something. But you won’t know exactly what it is reacting to.   

You have to test specific antibodies to antigens to know exactly what you are dealing with. These specific tests show whether you have elevations to a particular antigen.  

You can test IgE and IgG to wheat, casein, peas, pollen, pine trees, dust mites, and more. 

Regarding molds, you can test for some of the common molds that cause allergies like: 

  • Alternaria 
  • Aspergillus 
  • Cladosporium 
  • Mucor 
  • Stachybotrys 

Interestingly, even some less toxic molds like Cladosporium can trigger mold allergies. 

You can be allergic to 1 type or more than 1 type. 

For Mold Allergy testing, here are the IgE Ulta Lab Tests I would recommend starting with: 

Alcat Test 

You can also measure leukocytes in testing. Leukocytes are a type of white blood cell. They are part of your body’s immune system. 

Leukocyte testing may be used to look for conditions such as infection, inflammation, allergies, and leukemia. 

One such test is the Alcat Test. It measures food/immune reactions through stimulation of leukocytes with food or chemical extracts.  

The Alcat Test doesn’t focus on a single antibody. It measures individual responses to foods and other substances at the cellular level.  

Check out the Alcat Test here.

If you’ve figured out you do have a Mold Allergy, your allergy might be worse because you also have Mold Toxicity or Mold Colonization. 

And like you read earlier, if you have Mold Toxicity or Mold Colonization, that might be the root cause of your Mold Allergy…and MCAS. 

Read on to learn more. 

Is Mold Toxicity Making Your Mold Allergy Worse?  

Did you know that allergies aren’t necessarily for life? 

Sometimes, you can develop an allergy because of ongoing exposure to something your body sees as toxic. 

Like mold. 

These reactions are a way your body is: 

  1. Trying to rid your body of toxins  
  1. Let you know that something in your environment is hurting you 
  1. Trying to protect you from damage from antigens 

You can also develop an allergy if your immune system is out of balance. 

But if you can get your immune system in better shape, it’s possible that some of your allergies will improve, too. 

How does your immune system get out of balance? One of the most common ways I see this happen is mold. 

The toxins released by mold can severely dysregulate your immune system. 

Here’s how. 

Mycotoxins and Your Immune System 

There are many different types of molds.  

Toxic molds release toxins called mycotoxins.

Mycotoxins weaken your body’s systems. Including your immune system.   

They can also mess up your nervous system signaling. 

Enough exposure to these mycotoxins can take a toll on your body. 

When your immune system is weakened, you’ll have a harder time fighting off these mycotoxins. 

But your immune system can also become overreactive. That’s what happens when you develop Mast Cell Activation Syndrome. 

Your mast cells can start reacting to things they shouldn’t. 

Or they just don’t stop reacting when they are legitimately triggered, like with an infection. 

You can become hypersensitive when your system is overreactive like this. 

Do you feel like you react to everything? Are you down to just a few foods you can tolerate? Does sometimes even just smelling a fragrance send you into a flare? 

Mast cells can also get so dysregulated they stop reacting to things they should react to. 

For example, some people stop developing an immune response to viruses. Have you heard people say they never get sick?  

In some cases, they just aren’t developing an immune response anymore, which is worse than getting sick.  

That could be the work of mold and mycotoxins. 

I now suspect that my Mold Allergy was so horrible when I was a kid because I also had Mold Toxicity. 

Mold Toxicity dysregulated my immune system so badly! 

So, just what is Mold Toxicity? 

What Is Mold Toxicity? 

Mold Allergies produce allergic reactions like the symptoms you read about above. 

Mold Toxicity can result in atypical symptoms like neurological symptoms, intense anxiety and depression, numbness and tingling, and more.   

Mold Toxicity is the buildup of mold toxins (mycotoxins) in your body. This can happen from ongoing mold exposure in your environment.  

You may have more of a toxic load than your body can handle. Not just from mycotoxins, either 

Your toxic load also increases from things you eat, toxins in the air, toxins in your water, and so much more. 

But mycotoxins certainly top the list of things that can add to your toxic load. 

In short, your body may not be able to keep up with detoxing fast enough.  

Further, mycotoxins can damage detox pathways making it even harder to detox them. It’s a great survival mechanism for mold. But it’s not so great for you.  

Related Article: How to Detox Your Body from Mold Gently 

Mold Toxicity and the buildup of mycotoxins can also happen from Mold Colonization in your body. 

Mold Colonization is when mold spores are growing inside you. And they release these mycotoxins. 

That’s why you can be out of mold in your environment, but still suffer from the effects of mycotoxins. They may be inside you! 

Either way, when you have this buildup of mycotoxins, your body is fighting all the time. 

My immune system became over-reactive. Not only was it constantly fighting off the mold toxins inside my body, but it also started to fight off everything. 

I became hypersensitive and developed MCAS.

And remember when you read that you can develop an allergy because of ongoing exposure to something? 

Mold Toxicity and/or Mold Colonization are definitely keeping you exposed to mycotoxins. It’s possible then that your Mold Allergy is a result of Mold Toxicity and/or Mold Colonization. 

Next, here’s a breakdown of how you can have just 1 of these conditions or all 3. 

Mold Allergy vs Mold Toxicity vs Mold Colonization 

There are many possible combinations of mold issues. Here are a few ways Mold Allergy, Mold Toxicity and Mold Colonization may be related. 

Mold Allergy 

You can have a Mold Allergy with or without Mold Toxicity.  

You can also have a Mold Allergy with or without Mold Colonization. 

Mold Toxicity 

You can have Mold Toxicity with or without a Mold Allergy. 

You can have Mold Toxicity with or without Mold Colonization. 

Mold Colonization 

You can have Mold Colonization with or without a Mold Allergy. 

But if you have Mold Colonization, you will develop Mold Toxicity if the colonization isn’t addressed. 

To Recap 

  1. Mold Allergy is an immune response with typical allergic reactions symptoms. 
  2. Mold Toxicity is the buildup of harmful mycotoxins in the body. Symptoms may include those like allergic reactions, but they can also be atypical. 
  3. Mold Colonization is when mold is growing in your body and releasing mycotoxins. (Usually also accompanied by Mold Toxicity.) 

And, yes, it is possible to have just a Mold Allergy. You’ll remember you can be allergic even to molds that aren’t toxic to humans, like Cladosporium. 

However, if you suspect you’ve had mold exposure, you may want to consider if Mold Toxicity is making your Mold Allergy worse. 

If you do determine you have a Mold Allergy, what can you do? 

That’s next. 

How to Address Mold Allergy   

There are different ways you can approach a Mold Allergy. 

Let’s look at some of those next. 

Limit Environmental Exposure 

With a lot of allergens, you’ll be advised to limit mold exposure. 

In other words, if you have a peanut allergy, you shouldn’t eat peanuts. 

If you have a Mold Allergy, you should get away from moldy environments. 

Indoor Mold 

You can help make your environment less hospitable to mold by removing potential for dampness and water damage. 

  • Run a dehumidifier to help keep indoor humidity levels down. 
  • Be sure to use your exhaust fan to help with moisture when you shower and bathe. 
  • Do periodic house inspections to check: 
    • your roof isn’t leaking 
    • your plaster or paint isn’t bubbling (sign of moisture behind the walls) 
    • your basement floors and crawl spaces are properly sealed 
    • you have no pipe leaks under the sinks and elsewhere 
    • you have no appliance line leaks like your fridge or washer
    • your gutters are functional 
  • If you have mold growth, you may need professional mold remediation. Even a tiny strip of something like Stachybotrys can make you very ill. You don’t need to have much toxic mold at all to call for remediation.  
  • You can treat your house with a product like BioBalance. BioBalance is non-toxic and can be a good choice if you are chemically sensitive. It wets airborne spores and mycotoxins so they fall out of the air and can be cleaned up with dusting or vacuuming.  
Biobalance Haven Fog

I’ve seen BioBalance (but not other products) improve daily anaphylaxis to mold for a number of clients.

Please note, though, that treatments like this can help with symptom relief and buy you some time. But they are never a substitution for remediation.

Outdoor Mold 

While we mostly focus on indoor mold, there are reported cases of outdoor mold being a problem as well. 

I’ve worked with several clients who developed sinus symptoms, headaches, fatigue, and increased food sensitivities after gardening.  

One woman developed a red rash across her face and sinus problems after scrubbing her deck which had black mold.  

They all recovered after a mold detox protocol. That’s the good news. 

The other good news is that you don’t have to avoid the outdoors. 

The key is to be mindful of areas with decomposing leaves, manure, or compost. And be careful when cleaning visible mold off outdoor furniture or fixtures. 

Be sure to wear a mask to help avoid breathing in spores or mold toxins. 

And remember, if it smells musty, there’s mold.   

Medications for Mold Allergies 

If you go to a traditional doctor, it’s very likely you’ll be given some medication to help with your symptoms. 

And you may really need to use them, at least for a while, to get some relief. 

You may also be advised to take antihistamines. 

Related article: The Best Antihistamine for Histamine Intolerance and Mast Cell Activation Syndrome

Antihistamines aren’t all bad. But there are a couple things you should know. 

Over time, symptoms can continue to worsen if you just use antihistamines without addressing the root cause of your allergy. That means you’ll need more and more medications.  

The goal is to use medications when needed for symptom relief and to calm MCAS while addressing root causes. Then, when possible, to come off the meds after the root cause is addressed.  

I’ll talk more about the root cause approach in just a bit. 

Lastly, you’ve probably heard of getting allergy shots. 

Again, these may be helpful for some. 

But what I’ve seen is allergy shots often trigger people with MCAS. Reactions can include arm swelling at the injection site and body-wide flares.  

Again, I want to be sure that you understand that medications may be very useful for you.  

But I also want you to understand that what you really need to do is get to the root cause of what’s causing your allergic reactions in the first place. This is the true way to find lasting relief. 

Before you learn more about addressing the root cause of Mold Allergy, take a look at other options that may help.  

Low Dose Immunotherapy 

Some people do well with Low Dose Immunotherapy (LDI) or Low Dose Allergen Therapy (LDA).  

In these types of therapies, doses are given by administering a small drop (less than 1 milliliter) of the enzyme and antigen mixture under the tongue.   

Doses may be needed every 7 – 8 weeks.   


NAET is another method for addressing allergies that works for some people. It stands for Nambudripad’s Allergy Elimination Techniques. 

You use this drug-free method with a chiropractor or another health care practitioner. 

NAET uses body work, like acupuncture, acupressure, chiropractic adjustments and muscle response testing, to help detect allergies. 

NAET is also described as being able to help reprogram the brain’s response to allergens. 

To detect an allergy, you are asked to hold a sealed vial of an allergen. Like mold.  

If you are allergic to mold, when you hold the vial of mold, your muscles may either go limp or become extremely tense. 

The practitioner looks for these changes. 

Additionally, practitioners can use body work to desensitize you to each allergen.  

You can talk with your practitioner to see if this might be a route you want to explore. 

In my experience, if you have Mold Toxicity and Mold Colonization along with a Mold Allergy, NAET is usually not enough on its own and won’t get rid of Mold Toxicity or Mold Colonization.

However, I’ve seen it help a lot with Mold Allergy and other sensitivities.  

It can help you determine whether you have a Mold Allergy. But you’ll likely need to go through a detox protocol, too. 

But there’s one thing you must do regardless…You must look at what’s causing these allergies to begin with. 

That’s where the root cause approach comes in. 

What Is the Root Cause Approach?  

Earlier you read that Mold Toxicity may be the root cause of your Mold Allergy. 

Or it may be making your Mold Allergy symptoms worse. 

That means that if you are going to get long-term relief, you need to address mold. 

That may mean changes to your environment through mold remediation. 

And you need to detox your body from mycotoxins if mycotoxins are present. 

Whether you have Mold Toxicity or Mold Colonization, it’s important to address your body’s detox needs to get to the root of mold.  

Once mold has been addressed, you may start to see improvements in your immune dysregulation, too. For instance, your mast cells may not be so reactive. 

You can learn more about gently detoxing from mold in the MC360™ Precision Mold Master Class.

In this course, you’ll learn how to stabilize your health and introduce a gentle, mast cell-friendly detox protocol.  

You’ll learn the exact steps I’ve used to help hundreds of private clients.  

This course was designed specifically for those with Mast Cell Activation Syndrome and Histamine Intolerance.  

There’s an important order of operations to address mold toxins and colonization so you don’t cause a flare.  

You want the right supports and supplements. And you want to introduce them at the right time. 

Otherwise, you may make yourself worse. 

You’ll learn how to reclaim your health from mold in the MC360™ Precision Mold Master Class. 

You’ll learn exactly what you need to do to reclaim your health from mold!    

Once you detox from mold, you may find that your Mold Allergy improves, too. 

Have you dealt with a Mold Allergy? What helped you the most? 

Some links in this website are affiliate links, which means Mast Cell 360 may make a very small commission if you purchase through the link. It never costs you any more to purchase through the links, and we try to find the best deals we can. We only recommend products that we love and use personally or use in the Mast Cell 360 practice. Any commissions help support the newsletter, website, and ongoing research so Mast Cell 360 can continue to offer you free tips, recipes, and info. Thank you for your support! 


Hou, R., et al. (2017). Peripheral inflammatory cytokines and immune balance in Generalised Anxiety Disorder: Case-controlled study. Brain, behavior, and immunity, 62, 212–218. 

Immunoglobulin E (IgE) Defined. (n.d.). American Acadamy of Allergy, Asthma, & Immunology. Retrieved February 2, 2023, from 

What is NAET? (n.d.). 

Makkonen, K., Viitala, K. I., Parkkila, S., & Niemelä, O. (2001). Serum IgG and IgE antibodies against mold-derived antigens in patients with symptoms of hypersensitivity. Clinica Chimica Acta, 305(1–2), 89–98. 

Mold Allergy – Symptoms, Prevention, and Treatment | (2023, January 17). Asthma & Allergy Foundation of America. 

Mold. (2022, November 14). Centers for Disease Control and Prevention. Retrieved February 2, 2023, from 

Mold and Health. (2022, May 5). US Environmental Protection Agency. 

Moyer, M. W. (2012, April 25). Nothing to Sneeze at: Allergies May Be Good for You. Scientific American. 

Nathan, N., & Brewer, J. (2022). Mold and Mycotoxins: Current Evaluation and Treatment 2022 (2nd ed.). BookBaby.

NHS website. (2022, June 14). Anaphylaxis. 


  1. Chance

    Hi Beth! Your website has been the best source of consistent info since I started having MCAS issues ~3yrs ago. I recently discovered I also have notable mycotoxin/mold toxicity levels (RTL MycoTOX), as well as leaky gut (“Wheat Zoomer” test; Zonulin blood markers).

    Do you have any advice on how to find a doctor who can help? And/or what type of doctor/specialist you’d recommend? i.g. a GP, immunologist, infectious disease specialist, FMD, ND, etc

    I’ve been seeing a very expensive FMD (not covered by insurance), but sadly I’m finding he isn’t as knowledgeable in mold and MCAS as he led me to believe before all the tests and appointments.

    Thanks so much for everything you do for us!

    1. Jamie, Mast Cell 360

      Hi Chance! We’re sorry to hear you recently discovered you’re dealing with mold toxicity. Please email the team at and we will do our best to send you resources to hopefully find a mold literate practitioner. You’re also welcome to apply to the practice at

Add A Comment

Recipe Rating

The reCAPTCHA verification period has expired. Please reload the page.