How to Know if Mold is Causing Your Health Problems

by Dr. Susan Tanner

The telltale signs and symptoms of mold-triggered illness is a tricky and loaded subject, but I am asked about it frequently; therefore, I decided to do my best to tackle it with this article.  Buckle your seatbelts.

A few disclaimers before I begin:

1. This article is NOT meant to diagnose you with mold-related illness. Rather, its purpose is to share common symptoms and clinical presentations that I have seen in my many years of treating mold-exposed patients in my own practice.

2. Because mold and mycotoxins can impact individuals in many ways, there is no one absolute symptom.  Some symptoms may be caused by a variety or a combination of factors, so I ask you to keep this in mind as you assess yourself. 

3. You are unique. You have individual medical needs. Thus, the best course for getting a proper diagnosis is ALWAYS to seek evaluation and treatment by a mold-literate or environmentally trained doctor who can perform a thorough physical examination and order appropriate testing. Targeted testing and your specific patient history will ultimately be the best way to rule in or out mold-related illness.

Symptoms That Point to Mold

Now that the disclaimers are out of the way, I want to jump directly into the “main” symptoms that tend to indicate mold. In other words, when I have a patient seeking out my services, especially one with multiple symptoms affecting multiple organ systems and who has been to many doctors before me, I ultimately start to screen them for mold. It is not because mold is always the cause of their symptoms. It is because mold should be ruled out before we start digging deeper. If we move on to attempting to treat other causes or symptoms without ruling mold out, we often will not be successful and symptoms will continue to worsen.

1. Chronic sinusitis. This website is called Sinusitis Wellness for reason! In fact, the Mayo Clinic published a study citing fungus as the cause of over 90% of chronic sinusitis.  Frequent or recurring sinus infections need to be worked up for mold and fungi.  Fungal sinusitis can easily mimic a bacterial infection.  Antibiotics often help INITIALLY, but you are only clearing the secondary bacterial overgrowth with the medications and not the underlying fungus causing the infection.  Therefore, infections keep coming back.

What to do?  Ask for a fungal culture and sinus Xrays/CT scan to look for structural abnormalities and fungal balls.  If you cannot get a fungal culture done, you can try doing your own swab, much like a COVID test, and putting it on a mold plate. If high levels of mold are cultured, your environment needs thorough evaluation!

2. Unusual sensory symptoms. These symptoms can present as numbness or tingling in certain parts of the body, which may be persistent.  Pins and needle sensations from compression, such as when your “hand goes to sleep”, usually resolve with changing position, but in the case of mycotoxicity, it doesn’t alleviate with a change of position.  I have had some patients tell me that the first thing they noticed was that their backsides and backs of their legs were numb when they sat on the toilet. These are typically not painful sensations but are just “weird” which is how it has been described.

What to do?  Have your doctor perform some simple neurological tests checking sensation, vibratory sense, and reflexes to see if any other neurological illnesses need to be tested for or ruled out.

3. Dizziness, balance problems, and slow reflexes. If you find the need to steady yourself while walking down a hallway, feel off-balance frequently, or are slow to react to normal stimuli, you should consider that something like mycotoxins could be disrupting your nervous system.

Again, simple neurologic testing can help identify and rule out other causes, such as inner ear problems, biochemical imbalances such as an electrolyte imbalance, or extreme blood sugar fluctuations. Medication side effects also need to be assessed.

4. Excessive fatigue. With this kind of fatigue, I am not talking about being tired from physical exertion or stress.  The fatigue caused by mold exposure and experienced by some patients is not related to sleep, exercise, or mood.  This fatigue is caused by the impact of mycotoxins on the mitochondria of the cells, which are responsible for creating the energy required to drive every process of the body. Additionally, the inflammation in the small capillary beds caused by mycotoxins decreases oxygen flow into tissues, which can include the brain, muscles, and other organs.  Fatigue is one of the hardest to assess symptoms as it is very subjective with multiple causes.  One must rule out many things in assessing it–a complete list of which is beyond the scope of this article–but could include anemia and other blood disorders, medication side effects, and acute or chronic illnesses of many types.

5. Headaches. Headaches are another BIG subject because they can be vascular, musculoskeletal, or biochemical in origin, but mold can cause frequent headaches and ice pick-like pain behind the eyes.

6. Sudden alterations or fluctuations in mood. I almost did not bring this one up, as it touches on an area that is very sensitive to mold and mycotoxin sufferers. Because some patients have been labeled as histrionic or been told, “It’s all in your head,” some are hesitant to even discuss the direct impact that mold/mycotoxins can have on their mental well-being.  “Brain fog” should also be included in this discussion.  Some patients feel they have the sudden onset of dementia, as memory and thought processes become so impaired.  Neuropsychological studies have seen patterns in these symptoms which point to environmental causes, including mycotoxins and other chemicals.  When discovered and the patient is removed from the mold exposure quickly, these symptoms are reversible but time is definitely of the essence here!

As with fatigue, mood changes and brain fog can have multifactorial causes, but sudden changes require investigation. Disruption of neurotransmitters can and does happen in response to mycotoxins, so do not ignore these symptoms!

7. Allergies. Allergies can manifest as respiratory, such as asthma or chronic bronchitis, but also as skin eruptions.  The mechanism of allergic response is different from the manifestation of toxicity, but they can exist together or individually.  I do think there is a high incidence of those who are classically “mold allergic”, who then develop symptoms of mold toxicity with continued exposure. Thus, while their first symptom is the allergic expression of inflammation, their symptoms progress to chronic or autoimmune illnesses and diseases if the mold is not found and treated.

What to do? Read this previous article detailing mold allergy vs. mold illness.

Is Mold the Cause?

There are certainly other symptoms specific to individuals when mold and mycotoxins are problems but the ones I listed here are some of the most common.  When I take a patient’s history, I find that drawing a timeline of the onset of different health events is very helpful.  Some of the questions I ask and that you should also think about are:

How has your home or work environment impacted the onset of symptoms?

Do you feel better when you spend time away from home or work?

Has your home or office had a water or moisture intrusion?

How old is your HVAC system?

Do you have a humidifier attached to your air handler?

Is there condensation on your walls, ceiling, or inside your windows?

Do scents linger in your home long after cooking or cleaning?

Is there any visible mold or mildew growing inside your home?

Does water flow towards your foundation?

Do you have a crawlspace?

Have you become sensitized to foods, ingredients, or scents that you used to tolerate well? Patients impacted by mold and mycotoxins can become so sensitized that even “safe” things elicit increased or sudden symptom responses.

When in Doubt, Start Here:

1. See your physician. Basic labs and a good hands-on physical examination should absolutely be done to rule in or out other causes.

2. Check your environment. Monitor the indoor humidity. (It needs to be kept below 47%). Look for signs of water or moisture intrusion. If you have signs or know of water intrusion that was not addressed swiftly and correctly, you have mold growing on those building materials. Any water allowed to sit and to penetrate and keep building materials wet WILL grow mold. You can also do some testing yourself by putting mold plates out or swabbing your nose if you have sinus symptoms. If you want professional testing or advice, I recommend using the website to search for a qualified indoor environmental professional in your area.

3. If you already know you have been exposed to mold, seek the care of an environmental or mold-literate practitioner, for further testing and treatment. And as mentioned over and over in previous articles, your environment MUST be clean in order for you to get better, so move to a safe environment or find those mold sources and clean them up! Dr. Dennis’s Environmental Treatment Protocol can also be extremely helpful for those who cannot immediately move or remediate.

We hope you find this article helpful. Questions or comments may be submitted below or by emailing us at We love hearing from you!