Nationwide resource hub. No hype. Just facts, trusted links, and practical help.
Browse Free Guides & Checklists →Three practical paths. These pages help you navigate and prepare — they do not diagnose illness or replace care from a licensed clinician.
Use the symptom checklist to organize what you notice before you talk with a clinician.
A printable visit prep sheet for concerns, medicines, past tests and questions.
Practical indoor-air steps: sources, humidity, ventilation and filters — not a cure.
Want condition overviews next? See What These Conditions Are below, or browse all guides and checklists.
Practical, downloadable resources built to save you weeks of searching
Short, accurate overviews — always consult your doctor for diagnosis or treatment.
Getting ready for an appointment? Our free symptom checklist helps you organize what you notice, and our doctor visit prep sheet gives you a printable place for your concerns, medicines, past tests and questions. Neither one diagnoses anything, and what you enter stays on your device.
Understanding the condition and the medical debate
“Mold toxicity” isn’t a formal diagnosis; it’s a term many patients and some clinicians use for illness they connect to mold and other contaminants in damp or water-damaged buildings.
Health agencies agree that damp, moldy buildings are linked to stuffy nose, cough, wheeze, asthma and allergies, and to lung infections in people with weakened immune systems. Whether mold causes a longer-lasting, whole-body illness with fatigue and brain fog is still debated.
The step everyone agrees on: fix the moisture problem and remove mold safely.
Important Note: There is ongoing debate in medicine about “toxic mold syndrome.” While some providers focus on immune dysregulation, major organizations like the CDC emphasize allergies and infections rather than broad systemic toxicity.
A biotoxin-driven illness often triggered by mold
CIRS (Chronic Inflammatory Response Syndrome) is an illness model, developed by Dr. Ritchie Shoemaker, that describes a multi-system inflammatory illness after exposure to biotoxins, most often in water-damaged buildings.
According to Dr. Shoemaker’s theory, some people may have trouble clearing these toxins because of their genes, which can lead to a persistent inflammatory response.
CIRS practitioners diagnose it using exposure history, a symptom checklist, a vision contrast test and specific blood markers. The Shoemaker Protocol is the best-known and most-published treatment approach for CIRS.
Important: CIRS is still controversial in mainstream medicine. Some functional and environmental medicine practitioners recognize and treat it and report helping patients, but evidence is still limited, and major medical organizations often attribute symptoms to other causes.
When mast cells become over-reactive
MCAS (Mast Cell Activation Syndrome) happens when mast cells, immune cells involved in allergic reactions, release chemicals like histamine too easily, causing episodes of symptoms such as flushing, hives, itching, dizziness, stomach cramps or trouble breathing.
Triggers vary from person to person and can include heat, stress, exercise, certain foods, medicines and infections.
Doctors use two different sets of diagnostic criteria, so who gets diagnosed varies. Treatment usually combines avoiding triggers with medicines that block mast cell chemicals.
Important: MCAS is still not fully recognized by all medical institutions. Some functional and integrative practitioners report helping patients using broader diagnostic criteria, but evidence for that approach is still limited, and diagnosis and treatment can vary widely between providers.
A form of dysautonomia with major overlap
POTS (Postural Orthostatic Tachycardia Syndrome) is a form of dysautonomia in which the heart rate rises too much on standing, by 30 or more beats per minute (40 or more in teens), with symptoms like lightheadedness, a racing heart and fatigue.
It’s diagnosed with a stand test or tilt table test. It isn’t caused by anxiety.
Management usually starts with more fluids, extra salt with your doctor’s guidance, compression and a gradual exercise plan, with medicines added if needed.
Important: POTS is a real and recognized medical condition, but it is still frequently misdiagnosed or dismissed. Many patients wait years for a proper diagnosis. Early recognition and proper management can help many people feel and function better.
A connective tissue disorder with significant overlap
hEDS (Hypermobile Ehlers-Danlos Syndrome) is a heritable connective tissue disorder that causes loose, unstable joints and chronic pain. It is the most common type of EDS.
Its genetic cause hasn’t been found yet, so it’s diagnosed with a clinical checklist (the 2017 criteria) rather than a lab test.
Physical therapy and pain management are the core of care, and many people with hEDS also live with POTS or mast cell symptoms.
Important: hEDS is still under-recognized by many healthcare providers. Diagnosis can take years, and treatment is often multidisciplinary. Early recognition and proper management can help many people manage symptoms.
When everyday chemicals seem to trigger symptoms
MCS (Multiple Chemical Sensitivity, also called idiopathic environmental intolerance or IEI) describes symptoms in more than one body system, such as headaches, fatigue, trouble concentrating or breathing difficulties, that people report after low-level exposure to everyday chemicals like fragrances, cleaning products, smoke or paint.
There’s no validated diagnostic test. Questionnaires such as the QEESI are used for screening and research, alongside a check for other causes.
Practical steps focus on reducing exposures: fragrance-free and low-VOC products, good ventilation, and workplace accommodations when needed.
Important: MCS is debated in mainstream medicine. Its cause is unknown, and some mainstream medical groups say the evidence doesn’t support defining it as a distinct disease. The symptoms are real, and a careful medical evaluation can look for other treatable causes.
Cited guides to questions that often come up alongside mold and chemical sensitivity. Educational only — always consult your doctor.
What intestinal parasites are, how they’re actually tested, and what the evidence says about “parasite cleanses.”
Read the guideLead, mercury, arsenic and cadmium: where exposure comes from, proper testing, and which tests to skip.
Read the guideHumidity, ventilation, source control and choosing an air cleaner, without the marketing hype.
Read the guideWater quality reports, well testing, lead pipes, and what different filter certifications mean.
Read the guideWhat the MTHFR gene does, how common its variants are, why routine testing isn’t recommended, and the evidence behind methylation claims.
Read the guideWhat the COMT gene does, what “slow COMT” really means, why guideline groups don’t act on it, and the evidence behind functional claims.
Read the guideHow HLA-DR and DQ genes guide the immune system, their proven disease links, and the evidence behind “mold-susceptible” HLA claims in CIRS.
Read the guideMany patients and some clinicians report mold exposure as a trigger for MCAS; research so far is mostly lab-based. Connective tissue weakness in hEDS can worsen POTS. MCAS may also play a part in dysautonomia for some people, though these links are still debated. Many people report having 2–4 of these at once — sometimes called the “overlap” or “trifecta + CIRS.”
Understanding the connections helps you and your doctors create better care plans.
The Overlap Hub exists to connect people living with Mold Toxicity / CIRS, MCAS, POTS, and hEDS to clear, trustworthy community resources — so no one has to navigate these overlapping conditions alone.
You’re not crazy. You’re not alone. And you’re definitely not the only one whose symptoms don’t fit neatly into one diagnosis.
The Overlap Hub was created by HealingAfterMold in 2026 because too many of us were drowning in scattered information, conflicting advice, and the exhausting search for answers.
We believe knowledge is power, but only when it’s accurate, compassionate, and easy to find.
That’s why we built this free community resource hub: to gather the best, most up-to-date information, trusted organizations, testing & remediation guides, provider directories, and real-world tips in one calm, hopeful place. No hype. No pressure. Just honest, practical help.
Important: The Overlap Hub is not a medical provider and this site is not medical advice. All information is for educational purposes only. Always work with licensed healthcare professionals for diagnosis and treatment.
Welcome to The Overlap Hub.
You belong here. 💚
Stay connected with practical tips, real stories, and updates from HealingAfterMold on TikTok and Facebook.
Dr. Ritchie Shoemaker’s official site — diagnostic criteria, labs, protocols, and physician directory.
MCAS research, patient guides, and provider directory.
hEDS criteria, management, and global resources.
POTS information and research.
Mold education and safe-home resources.
Recipes, supplements and patient guides focused on MCAS and mold, a good place to browse when you’re looking for ideas.
Tools many in the community have found helpful for mold, air quality, water, and non-toxic living.
A quick heads-up: some of the product links and discount codes on this page are affiliate links or codes. If you buy through them, we may earn a small commission at no extra cost to you. It helps keep The Overlap Hub free.
Purifiers combining H13 HEPA and carbon filtration with UV-C and bipolar ionization. We like having a simple option to share with anyone working on the air in their home.
Visit Air Oasis →A countertop reverse osmosis water filter, a simple way to filter your drinking water without any plumbing work.
Visit AquaTru →Fragrance-free, non-toxic cleaning products. We like that they keep cleaning simple and scent-free.
Visit Branch Basics →EC3’s mold spray and air fogger products, an option we’re glad to share as you work on your home.
Visit EC3 →Liquid herbal supplements from a company we know personally. BioRay is the only supplement brand we use in our own home now.
Visit BioRay →Use code LIZHEALINGAFTERMOLD at checkout
Vibration plates and recovery equipment for anyone who likes to move at home, at their own pace.
Visit LifePro Fitness →Simple swaps and trusted options many in the community use to reduce daily toxin exposure
Organic cotton, hemp, and OEKO-TEX certified options.
Pact Organic → Rawganique →Fragrance-free, clean-ingredient products.
Branch Basics → Earth Mama → Dr. Bronner’s →Non-toxic cookware, utensils, and storage.
Caraway → GreenPan → Our Place → Pyrex → GIR → Kikcoin →GOTS-certified organic options and low-VOC furniture.
Avocado Green Mattress → Woolroom → Wooden Dot → Kalon Studios → The Citizenry →Always introduce new products slowly and patch-test if you have MCAS. Pay special attention to VOCs and off-gassing with new furniture, mattresses, and textiles.
ERMI, HERTSMI-2, Actino & endotoxin dust testing, widely used by CIRS patients and practitioners.
envirobiomics.com →EMMA environmental mold & mycotoxin testing + urine mycotoxin panels.
realtimelab.com →Use code elizabethtox10 at checkout
Official Shoemaker-protocol remediation steps, house-hunting guide & free resources.
survivingmold.com →Find certified mold remediators & inspectors across the entire US.
normi.org →Official government guidelines for safe mold cleanup and remediation.
epa.gov/mold →Plus national directories through The Mast Cell Disease Society, Ehlers-Danlos Society, and Dysautonomia International.
Fragrance is the most commonly reported trigger. A room-by-room guide to removing sources, reading labels, ventilating and filtering, plus what functional practitioners add.
Invasive aspergillosis, mucormycosis and other mold infections are rare but serious. Who is at risk, the warning signs, and why they need urgent medical care.
The tests and treatment steps people ask about for CIRS, what each one is meant to show, and where the mainstream view and the evidence stand.
What Leviticus 13 and 14 say about mildew in houses and clothing, why translations differ, and how the steps compare with today’s mold guidance.
The symptoms people most often report, which ones the evidence backs, and how to get a careful workup.
What these DNA dust tests measure, what EPA says about them, how CIRS practitioners read the scores, and how to test wisely.
Fix the water, size up the job, hire well, contain the mess and check it’s really done, based on EPA guidance.
What lab research shows, what’s still unproven, and practical steps if you think mold is part of your flares.
An emergency plan, testing during a flare, trigger tracking, medicines to discuss and ways to calm your system.
How often these conditions show up together, what’s still debated, and how to coordinate care when you have more than one.
Overlap Assistant
Answers instantly • Not medical advice