The most common mold exposure symptoms are a stuffy nose, sore throat, cough or wheeze, burning eyes and skin rash, according to the CDC. Mold toxicity symptoms like fatigue, brain fog and headaches are reported too, but the evidence tying them to mold is thinner and debated.
All of these overlap with allergies, colds, stress and more. So the most useful question isn't on any checklist.
Where were you when you felt worst?
Mold lives in buildings. When it's making you sick, your symptoms tend to follow the building, and you can track that.
What are the symptoms of mold exposure?
Mold exposure symptoms usually show up where air meets your body: your nose, throat, eyes, lungs and skin. People with asthma or a mold allergy may have severe reactions, per the CDC.
A 2004 Institute of Medicine report found sufficient evidence linking indoor mold to cough, wheeze and upper respiratory symptoms in healthy people, asthma symptoms in people with asthma, and hypersensitivity pneumonitis (HP), an immune reaction that inflames the lungs.
Mold can irritate your eyes, skin and airways even if you aren't allergic, per the EPA. People with weakened immunity or chronic lung disease can also get lung infections from mold, and our guide to a weak immune system covers the warning signs.
“21% of of current US asthma cases, about 4.6 million, were estimated to be attributable to dampness and mold at home." - Source: Mudarri and Fisk, Indoor Air, 2007
12 potential mold poisoning symptoms
- Cognitive difficulties (brain fog, poor memory, anxiety)
- Pain (especially abdominal pain, but can include muscle pain similar to fibromyalgia)
- Unexplained weight gain or weight loss
- Numbness and tingling in extremities or other areas of the body
- Metallic taste in the mouth
- Vertigo or dizziness
- Tinnitus (ringing in the ears)
- Digestive issues (especially limited tolerance to food, persistent bloating)
- Significant fatigue that interferes with daily activities
- Changes in mood
- Excessive thirst and dehydration, bed-wetting in children
- Symptoms that resemble hormone imbalances (hair loss, rashes)
What are the 10 warning signs of mold toxicity?
These 10 warning signs run from best supported to least. Signs one through seven are recognized effects of damp, moldy buildings. The last three rest mostly on small or self-reported studies.
- Symptoms that ease within hours or days of leaving a building and return when you go back, a pattern CDC workplace guidance uses to flag work-related illness.
- A stuffy or runny nose, sneezing or congestion that won't clear, though months of congestion has other causes too.
- Lingering cough or throat clearing, sometimes worse when you lie down.
- Wheezing, chest tightness, or asthma that's suddenly harder to control.
- Red, itchy, watery or burning eyes.
- A rash or itchy skin.
- Shortness of breath, fever, chills or aches starting hours after time in a damp or dusty space, a possible sign of HP.
- Headaches and fatigue.
- Brain fog or trouble concentrating.
- Numbness, tingling, dizziness or other nerve-type symptoms.
Among 5,775 Swedish adults, home dampness, mold and mold odor were risk factors for symptoms, especially headache.
Still, the American Academy of Allergy, Asthma and Immunology (AAAAI) says mold allergy "is not usually a cause of chronic symptoms such as headache and fatigue."
In a questionnaire study of 90 nurses and midwives from a water-damaged Finnish hospital, 62% reported brain fog, versus 11% of 45 unexposed coworkers. It's small and self-reported, so it can't show cause. Our guide to clearing brain fog covers other drivers.
In mice, inhaled Stachybotrys spores changed memory performance alongside brain inflammation, even with the toxins removed. Mice aren't people.
What are the weird symptoms of mold toxicity?
The unusual symptoms linked to mold toxicity, like a metallic taste, numbness, tingling and vertigo, come mainly from clinics that treat mold-related illness. One such clinic called them routine in a study of 17 patients.
Parsley physician assistant Megan McElroy, PA-C, has said "the symptoms of mycotoxin-induced illness vary and have no pattern, and they are not unique to this illness." So the timing in sign one tells you more than any odd symptom.
Mold exposure vs. mold toxicity vs. mold poisoning: what's the difference?
Mold exposure means breathing in or touching mold. A debated label, mold toxicity describes chronic, body-wide illness blamed on mold toxins. In medical terms, mold poisoning usually means eating food contaminated with mycotoxins.
Mycotoxins are toxic compounds some molds make. The World Health Organization describes them as toxins found in food: large doses of aflatoxins can cause acute, sometimes life-threatening poisoning, usually through liver damage.
Mold terms, what they mean, and how established they are
| Term | What it usually means | Medical status |
| Mold allergy | An immune reaction to spores: sneezing, stuffy nose, itchy eyes | Well established |
| HP | Lung inflammation from an immune reaction to inhaled mold or dust | Well established; uncommon |
| Mold infection | Mold growing in the body, usually the lungs | Well established; mainly with weakened immunity |
| Mold toxicity or illness | Fatigue, brain fog and other symptoms blamed on mold toxins | Debated; no agreed test |
| CIRS | Chronic inflammatory response syndrome, proposed after time in water-damaged buildings | Debated; early studies are small and clinic-based |
| Mold poisoning | Illness from eating food contaminated with mycotoxins | Well established |
The AAAAI's 2006 position paper called many newer mold-related illnesses "largely or completely unproved." And the EPA says symptoms beyond allergy and irritation "are not commonly reported as a result of inhaling mold."
None of this means your symptoms aren't real. The label is unsettled, and a careful workup still looks for every treatable cause.
Are black mold symptoms different?
No. Black mold doesn't cause a distinct set of symptoms, and the CDC says all molds should be treated the same for health risks and removal.
The term usually means Stachybotrys chartarum, a greenish-black mold that needs constant moisture and grows on drywall and paper, per the CDC. No test proves a link between it and particular symptoms, the CDC adds.
So color is the wrong thing to watch. Moisture is the right one.
How do you know if mold is making you sick?
The clearest sign that mold is making you sick is a pattern: symptoms that track one building, plus signs of moisture or mold in it.
Start with the building. Mold can smell musty and look like spots of many colors, per the CDC. In a survey of 36,541 parents in six Chinese cities, a moldy odor and humid air at home had the strongest links to symptoms, including headache and fatigue.
Then track yourself. For two weeks, note your symptoms morning and night and where you spent the day. Better on vacation and worse at your desk is useful information.
We'd rather see two weeks of those notes than any single lab result.
The CDC doesn't recommend home mold testing, since there are no set standards for acceptable levels. If you see or smell mold, remove it and fix the moisture. For allergy-type symptoms, an allergist can confirm a mold allergy with skin prick testing.
What about urine mycotoxin tests?
Urine mycotoxin tests aren't FDA-approved, and levels that predict disease haven't been established, according to a CDC report. Mycotoxins are in many foods, so they turn up in healthy people's urine too.
Some clinicians, including some at Parsley, use these panels as one clue alongside your history and a look at the building itself.
"I never place the entire diagnosis of mycotoxin illness on tests alone." - Megan McElroy, PA-C, physician assistant at Parsley Health
What else could be causing your symptoms?
Many conditions mimic mold symptoms.
Allergies can leave you tired, and flushing or hives after certain foods can point to histamine intolerance. Fatigue with joint pain or rashes may be among the signs of autoimmune disease.
A body that feels heavy and tired can reflect thyroid problems or nutrient gaps, and hormonal imbalance can bring hair loss, mood changes and weight shifts. And fatigue can hit women suddenly for other reasons
Parsley clinicians are board-certified in conventional medicine with advanced training in functional medicine, so they can prescribe medication when needed and also look for what's driving symptoms.
That starts with the timeline: when symptoms began, where you live and work, and any leaks, floods or musty rooms. A clinician may check thyroid function, iron and inflammation, order allergy or lung tests, and add advanced lab testing when it fits.
If mold looks like part of the picture, see how mold toxicity is treated. Parsley's care for unexplained symptoms is built for this kind of puzzle.
Frequently asked questions about mold toxicity and mold poisoning
What are the signs of mold exposure in toddlers and kids?
Kids can have the same symptoms as adults. The CDC notes research suggesting early mold exposure may be linked to asthma in some children, especially those genetically prone to it. Call your pediatrician about any wheezing.
Can you get sick from eating moldy food?
You can. Some molds on food cause allergic reactions and breathing problems, and a few make mycotoxins that can make you sick, per the USDA. Don't sniff moldy food, and throw out anything covered in mold.
Will mold symptoms go away once the mold is removed?
Often they improve. A Cochrane review of 12 studies with 8,028 people found moderate- to very low-quality evidence that repairing mold-damaged homes and offices eased asthma symptoms and respiratory infections in adults. Chronic HP can permanently damage the lungs, so it needs follow-up.
Can mold make you tired?
It may. A survey of more than 36,000 Chinese parents linked home dampness and mold to fatigue, but self-reports can't prove cause. If exhaustion leads, our guide to chronic fatigue covers other causes to check.
This article is educational and isn't a substitute for medical advice. Talk with your clinician about your own symptoms, exposures and testing.
What are the common types of mold?
Potentially more than 1 million types of mold exist. Molds generally fall into three main classifications: allergenic, toxigenic, and pathogenic. Some molds may fall into more than one category.
Allergenic molds may cause an allergic reaction in people with mold allergies. More than 150 allergenic molds could cause symptoms. Common allergenic molds include Alternaria, Helminthosporium, and Aspergillus.
Toxigenic molds can cause inflammation that may lead to mold toxicity symptoms. A common toxigenic mold is Stachybotrys chartarum, commonly called black mold.
Pathogenic molds can cause infection. Common pathogenic molds include those in the Aspergillus species.
Is black mold harmful?
The color of a mold doesn't dictate its danger level. All types of mold, including black mold, can cause reactions in those who have a mold allergy or sensitivity. Black mold, known as Stachybotrys chartarum thrives on warm damp wood and drywall.
How long does it take to get sick from mold exposure?
If you have a mold allergy, you might react as soon as you encounter mold spores. If you do not have an allergy but are sensitive to mold, symptoms may take time to appear.
Can you heal from mold toxicity?
The short answer is yes. The first step to healing will be to avoid exposure. This may involve taking mold remediation steps, changing diet, and more. The second step will be to incorporate health and lifestyle changes. These may include addressing allergies, taking supplements or changing diet to help reduce inflammation, and more.
References:
1. Centers for Disease Control and Prevention. Mold. Updated February 7, 2024. Accessed November 6, 2026. https://www.cdc.gov/mold-health/about/index.html
2. Institute of Medicine. Damp Indoor Spaces and Health. National Academies Press; 2004. doi:10.17226/11011
3. US Environmental Protection Agency. Mold and health. Updated February 18, 2026. Accessed November 6, 2026. https://www.epa.gov/mold/mold-and-health
4. Mudarri D, Fisk WJ. Public health and economic impact of dampness and mold. Indoor Air. 2007;17(3):226-235. doi:10.1111/j.1600-0668.2007.00474.x
5. Centers for Disease Control and Prevention. Mold in the workplace. Updated October 8, 2026. Accessed November 6, 2026. https://www.cdc.gov/niosh/mold/about/index.html
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7. American Academy of Allergy, Asthma and Immunology. Mold allergy. Accessed November 6, 2026. https://www.aaaai.org/conditions-treatments/allergies/mold-allergy
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10. Shoemaker RC, House D, Ryan JC. Structural brain abnormalities in patients with inflammatory illness acquired following exposure to water-damaged buildings: a volumetric MRI study using NeuroQuant. Neurotoxicol Teratol. 2014;45:18-26. doi:10.1016/j.ntt.2014.06.004
11. World Health Organization. Mycotoxins. Published October 2, 2023. Accessed November 6, 2026. https://www.who.int/news-room/fact-sheets/detail/mycotoxins
12. Bush RK, Portnoy JM, Saxon A, Terr AI, Wood RA. The medical effects of mold exposure. J Allergy Clin Immunol. 2006;117(2):326-333. doi:10.1016/j.jaci.2005.12.001
13. Centers for Disease Control and Prevention. Facts about Stachybotrys chartarum. Updated May 29, 2024. Accessed November 6, 2026. https://www.cdc.gov/mold-health/data-research/facts-stats/index.html
14. Hypersensitivity pneumonitis. MedlinePlus Medical Encyclopedia. National Library of Medicine. Reviewed April 10, 2025. Accessed November 6, 2026. https://medlineplus.gov/ency/article/000109.htm
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16. Kawamoto M, Page E. Notes from the field: use of unvalidated urine mycotoxin tests for the clinical diagnosis of illness, United States, 2014. MMWR Morb Mortal Wkly Rep. 2015;64(6):157-158. https://pmc.ncbi.nlm.nih.gov/articles/PMC4584707/
17. Breathing difficulty. MedlinePlus Medical Encyclopedia. National Library of Medicine. Reviewed April 1, 2025. Accessed November 6, 2026. https://medlineplus.gov/ency/article/003075.htm
18. US Department of Agriculture Food Safety and Inspection Service. Molds on food: are they dangerous? Accessed November 6, 2026. https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/molds-food-are-they-dangerous
19. Sauni R, Verbeek JH, Uitti J, Jauhiainen M, Kreiss K, Sigsgaard T. Remediating buildings damaged by dampness and mould for preventing or reducing respiratory tract symptoms, infections and asthma. Cochrane Database Syst Rev. 2015;(2):CD007897. doi:10.1002/14651858.CD007897.pub3\
This article is educational and isn't a substitute for medical advice. Talk with your clinician about your own symptoms, exposures and testing.
