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Mold, Histamine Intolerance, and Mast Cell Activation Syndrome: Everything You Need to Know

Finding mold in your home is more than just a small annoyance. Mold exposure can have serious health consequences and it may be the reason behind your mysterious chronic symptoms. Mold can hide inside and outside your home and spread its spores and mycotoxins through the air. Mold can increase histamine intolerance and trigger mast cell activation syndrome (MCAS) leading to a variety of chronic symptoms, including allergies, headaches, fatigue, brain fog, congestion, skin problems, and anxiety. The good news is that there are natural solutions you can use to overcome mold toxicity, histamine intolerance, and MCAS.

In this article, you will learn what histamine intolerance and MCAS are. You will understand what mold is and what problems are linked to chronic mold exposure. I will explain how mold, histamine intolerance, and MCAS are connected. I will share my natural solutions for mold toxicity, histamine intolerance, and MCAS.

What Is Histamine Intolerance?

Histamine plays a critical role in your body. It is responsible for many important bodily functions, including communicating with your brain, fighting off allergens as part of your immune response, and promoting stomach acid release to aid digestion. While healthy levels of histamine are necessary and good for your health, too much histamine is not healthy. 

Histamine intolerance means that you have too much histamine, usually because you can’t break it down properly, which can result in various symptoms and health issues, including allergies, chronic congestion, chronic runny nose, headaches and migraines, hives, eczema, psoriasis, fatigue, anxiety, diarrhea, tachycardia, low blood pressure, hypertension, flushing, crawling sensation on your skin, vertigo, abnormal menstrual cycle, hormonal problems, asthma attacks, and more. You can learn more about histamine intolerance in this article (1)

What Is Mast Cell Activation Syndrome?

Your mast cells play a critical role in your immune system. They are white blood cells that are found in tissues throughout your body. They can be found in your skin, digestive tract, respiratory tract, urinary tract, reproductive organs & surrounding nerves. They may also occur in your blood due to infections and diseases that mast cells help repair after the initial health threat is gone. Mast cells also store inflammatory mediators inside granules that also include histamine. During allergic reactions, mast cells are activated and trigger an allergic response.

Mast cell activation syndrome (MCAS) is a complex issue that involves many different systems in your body leading to a large variety of symptoms. You may develop MCAS due to a variety of triggers, including mold, heavy metals, chemicals, fragrances, allergens, medications, infections, food, and alcohol. If you have MCAS, some or all of these triggers can cause your mast cells to release inflammatory mediators and histamine. This can lead to a variety of symptoms, including rashes, hives, itching, headaches, heart palpitations, low blood pressure, weight changes, loss of appetite, fatigue, dizziness, weakness, digestive issues, chest pain, anxiety and vision changes. To learn more about MCAS, I recommend this article.


Symptoms of histamine intolerance and MCAS can be quite similar. However, there are some differences between the two. Histamine intolerance develops due to excess histamine and histamine build-up in your body, while in MCAS, your mast cells are being triggered spilling histamine and other chemicals into our body resulting in symptoms. I believe that MCAS is one of the primary causes of histamine intolerance. However, it may not be the cause for everyone. You may experience histamine intolerance without having MCAS (2, 3, 4, 5)

Mold, Histamine Intolerance, and Mast Cell Activation Syndrome

Mold is a fungus that is known for its ability to grow on almost anything and thrive under many conditions, especially in a warm and moist environment. They release mycotoxins in the air and lead to consequent health issues. 

Mold is versatile and has many types and forms. This also means that mold can grow both indoors and outdoors. Your bathroom, kitchen, and basement are some of the most common areas molds may hide, however, they can appear anywhere else, especially in damp, wet, and warm environments.

The problem is that mold can spread far and wide. You may initially have mold in one tiny spot in your home, but its microscopic spores can travel far. You may breathe them in through the air. They also may take home in other areas of your house leading to more mold growth. There are about 1,000 species of mold in the United States. Some of the most common molds that may affect your health include aspergillus, Cladosporium, Alternaria, Memnoniella, Penicillium and Stachybotrys.

Chronic exposure to mold can be dangerous. It can lead to mold toxicity symptoms, including fatigue, brain fog, headache, skin issues, respiratory problems, and nausea. Mold exposure and mold toxicity may also increase histamine intolerance and trigger MCAS.

Mold releases mycotoxins that have toxic effects on your body. As a response, your mast cells release histamine and other chemicals to attack and destroy these harmful mold toxins. The problem is that if you are being continuously exposed to mold, your body will develop a chronic state of inflammation, your immune system will be on a constant alert, and your body will be in a constant state of defense. 

Due to chronic mold exposure and on-going inflammation, you can develop histamine intolerance. Your mast cells end up over-producing histamine in order to protect your body from mold toxins. However, your body won’t be able to keep up with all the histamine, which can lead to histamine intolerance and consequent symptoms (6, 7, 8, 9)

Natural Solutions for Mold, Histamine Intolerance, and MCAS

If you’ve been exposed to toxic mold and experiencing symptoms of histamine intolerance or MCAS, I have good news for you. You can resolve your symptoms by using simple natural solutions. Here is what I recommend: 

Remove Mold from Your Home and Reduce Mold Exposure

First things first, if you have mold in your home, you need to remove it (unless you can move to a mold-free home!). If the mold-affected area is over 10 square feet or 1 square meter, call a professional mold remediation specialist. The problem is bigger than you can handle on your own. However, if you are only dealing with a smaller area, you can probably take care of it yourself.

You may try these self-removal options to take care of your mold problem:

  • Try a mix of one teaspoon of baking soda and 2 cups of water to use on affected surfaces
  • Use undiluted white vinegar on hard surfaces in your bathroom and kitchen
  • Use a 50/50 mix of ammonia-water solution as a spray. Leave it on the affected surface for 2 to 3 hours them rinse it well.
  • NEVER mix all-purpose cleaners or bleach with ammonia. They can create toxic fumes that can be dangerous to your health.

Don’t forget about addressing any underlying problems that may drive mold:

  • Remove any moldy and old rugs, carpeting, paint, or wallpaper
  • Clean or dispose of any moldy shower curtains, clothing, and other items
  • Fix moisture leaks and water damage issues
  • Reduce indoor humidity and keep it between 30 and 50 percent
  • If you hang your clothes to dry, ideally, do it outside
  • Always wipe down wet tiles after you shower
  • Keep the detergent compartment of your washing machine open
  • Make sure your home is ventilated well
  • Use a high-quality indoor air filtration system
  • Check your indoor plants and keep the mold off of them
  • Clean and repair the roof gutters of your home
  • Direct any rain or melted snow or ice away from your house
  • Keep your home clean
  • Check for signs of mold growth regularly and address any mold immediately

A word on exposure at work:

Unfortunately, mold exposure may happen at your work. At least half of the buildings in North America are affected by mold. This can be difficult if you are unknowingly exposed. If you can use a high-quality air filtration system at your office or office area. Talk to HR and encourage them to do regular mold checks and use prevention strategies. If you notice any signs of mold, speak with HR immediately. If there is an ongoing mold issue at your job, you may want to consider looking for new employment if it’s possible.

Get Tested for Mold Toxicity

If you have symptoms of mold toxicity or have been exposed to mold, it is important to get tested. Working with a functional medicine doctor, like myself, can help you with this. Just schedule a consultation today.

Detoxify Your Body from Mold

If you have been affected by chronic mold exposure and mold toxicity, you need to detoxify your body from mold. Here is what I recommend:

  • Check house & workplace for mold exposure (consider ERMI test)
  • Get body tested for mold toxicity
  • Detoxify Your Body from Mold
    • Hydrate well
    • Support detoxification through sweating ie. infrared sauna
    • Consider working with a practitioner to help with mold protocol
  • There are various other products I use to address mold depending on the person’s history and tolerance to supplements.
  • Recover Your Body from Histamine Intolerance and MCAS
    • Eat a low-histamine diet
    • Support your liver
    • Consider histamine supporting supplements like quercetin, nettle & others. My HistoRelief supplement has a blend of these ingredients & more.

Support Your Gut

Chronic mold exposure and mold illness can lead to gut infections and gut health issues. Gut microbiome imbalances and gastrointestinal problems can increase the risk of histamine intolerance and POTS. If you are dealing with gut imbalances, supporting your gut health is key.

Follow a healthy gut-friendly diet rich in greens, vegetables, sprouts, low-glycemic index fruits, herbs, spices, grass-fed meat, pasture-raised poultry, wild-caught fish, and wild game. If you are not dealing with histamine intolerance, you may add some probiotic-rich fermented foods, such as sauerkraut, kimchi, fermented herbs, yogurt, kefir, or kombucha. However, since fermented foods can drive histamine, if you have histamine intolerance or MCAS, avoid these foods.

If you are dealing with both histamine intolerance and gut health issues, I recommend working with a functional medicine practitioner (like me) to test your gut and see if opportunistic bacteria, yeast overgrowth, parasites, H. pylori and/or leaky gut can be what is driving your histamine issue. 

Support Your Body with an Anti-Inflammatory Diet and Healthy Lifestyle Strategies

Following a healthy, anti-inflammatory diet and following healthy lifestyle strategies, such as moving your body, reducing stress, and sleeping enough, are critical for your recovery. I recommend that you follow an anti-inflammatory, nutrient-dense diet. Remove inflammatory foods, including refined sugar, refined oil, artificial ingredients, gluten, food sensitivities, deep-fried food, junk food, and overly processed foods. Eat lots of greens, vegetables, sprouts, herbs, spices, fruits, grass-fed meat, pasture-raised poultry, pasture-raised eggs, fresh wild-caught fish and seafood, and wild game. Drink plenty of water, at least ten glasses per day

Move your body throughout the day. You may try dancing to your favorite songs, taking a stroll in the park, stretching regularly, and playing with your kids or pets. Exercise at least 20 to 30 minutes five days a week and move your body regularly. I recommend getting 10 to 15K steps in a day if you can. Add resistance and strength training to your routine. 

To reduce stress and improve sleep, I recommend practicing breathwork, meditation, positive affirmation, journaling, yoga, grounding, and time in nature for stress and anxiety reduction. Taking an Epsom salt bath is another great way to relax your muscles, calm your mind, and detoxify your body. Make sure to sleep at least 7 to 9 hours a night.

Recover Your Body from Histamine Intolerance and MCAS

As you’ve learned, histamine intolerance is a common consequence of mold exposure or mold-related gut health issues and a common underlying issue behind POTS. If you are dealing with histamine intolerance, addressing mold toxicity and eating an anti-inflammatory diet won’t be enough.

If you have histamine intolerance or MCAS, I recommend that you follow a nutrient-dense and low-histamine diet. Eliminate all histamine foods for one to three months. After this Elimination phase, slowly re-introduce them one by one following The 4-Phase Histamine Reset Plan. To understand each step of this simple yet refined system, I recommend that you read my book, The 4-Phase Histamine Reset Plan: Getting to the Root of Migraines, Eczema, Vertigo, Allergies and More where I explain everything about histamine intolerance and each phase of the plan in detail. You will also find my favorite low-histamine recipes to nourish your body. 

To support your body and reduce histamine intolerance, I recommend HistoRelief. It is a synergistic blend of nutrients, including Tinofend®, quercetin, nettle leaf, vitamin C, and bicarbonate salts, that provides natural support to balance your immune response, inflammation reduction, and histamine release.

Final Thoughts

Mold can be found in our indoor and outdoor environment, especially in warm, damp, and moist areas. Mold toxicity can trigger MCAS, increase histamine production, and lead to histamine intolerance and related symptoms. Follow my natural solutions to overcome mold toxicity, histamine intolerance, and MCAS. 

If you are dealing with symptoms of histamine intolerance and mold illness, I invite you to schedule a consultation with us. We can help identify the root cause of your condition and recommend a personalized treatment plan to repair your body and regain your health and well-being. Schedule your consultation here. I also recommend that you check out my Histamine Online Program.

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Hi, I am Dr. Becky Campbell. I work with men and women who’ve had a health set back and are willing to do whatever it takes to reach optimal health so they can perform their best in their careers and be fully present with their family again.