The Illness Hiding in the Walls

A physician’s guide to mold-related biotoxin illness — and why some patients never get better until someone asks about the building

When Steve first walked into our functional medicine practice in Richmond, Virginia, in the fall of 2016, he looked like someone whose life had been quietly stolen from him.

Not all at once. Not dramatically. But piece by piece.

He had been a college soccer player. Strong. Disciplined. The kind of person who knew what his body could do and how far he could push it. He was planning to start medical school that year. His future was not vague or theoretical — it was scheduled.

Then something changed.

His energy collapsed. His concentration faded. Sleep became unreliable. He lost nearly twenty pounds of muscle. His body hurt. His stamina disappeared. The person who had once trained, studied, competed, and prepared for a demanding career in medicine now struggled to understand why he could not simply feel like himself again.

He had already seen multiple specialists. He had taken multiple medications. The labels had started to accumulate: new-onset hypothyroidism, fibromyalgia, chronic fatigue syndrome, stress. There was also the old tick bite, which raised another question entirely.

Was this Lyme disease? Was it autoimmune? Was it just stress? Was his thyroid the whole story? Or was something else hiding underneath the surface?

This is where many patients with complex chronic illness find themselves: standing in the gap between “your labs look fine” and “I know something is wrong.”

Steve’s story is not rare. In fact, it may be far more common than most clinicians realize.

In this series, I want to explore an illness that affects untold numbers of people, shows up every day in primary care clinics, and yet is often overlooked. It is commonly called mold toxicity or mold-related biotoxin illness. Its more formal name is Chronic Inflammatory Response Syndrome, or CIRS.

In Part One, we will begin with the most basic question: what is mold-related biotoxin illness, and how big might this problem actually be?

In Part Two, we will look at the history of its discovery, the diagnostic process, and the underlying biology.

In Part Three, we will walk through the treatment framework and what recovery can look like.

For now, let’s begin where the mystery often begins.

Not inside the body.

Inside the building.

Part One: Understanding Our Mold Problem

The Potential Disease Load

According to data from the United States Government Accountability Office, approximately 50% of buildings in the U.S. have some form of water damage.[1]

That number should stop us for a moment.

Water damage does not always mean a dramatic flood or a ceiling collapse. It can be a slow roof leak. A damp crawl space. A poorly sealed window. A pipe behind a wall. A basement that never quite dries. A school building with years of moisture intrusion. An office with a persistent musty smell that everyone learns to ignore.

Now add a second piece of the puzzle.

Approximately 25% of the population appears to have a genetic susceptibility to the accumulation and inflammatory effects of biotoxins — microscopic particles, gases, and chemicals released from living organisms, including bacteria, viruses, and fungi.[2]

If roughly half of our buildings may have water damage, and a meaningful portion of the population may be genetically susceptible, then we have to ask an uncomfortable question:

How many people are living, working, and studying in environments that are quietly keeping their immune systems activated?

We do not yet have large-scale population studies that can tell us the exact size of the problem. But the potential disease load is enormous.

CIRS can also overlap with, trigger, or complicate other immune-related conditions. In some patients, it may spill over into the acquired immune system and appear alongside conditions such as autoimmune thyroid disease, gluten immune sensitivity, celiac disease, lupus, rheumatoid arthritis, and others.

This does not mean every case of fatigue, thyroid disease, pain, or autoimmunity is caused by mold exposure. It does mean that water-damaged buildings deserve a more serious place in the conversation about chronic inflammatory illness.

And for many patients, that conversation never happens.

The Symptoms of Mold Toxicity

One of the reasons CIRS is so often missed is that it rarely announces itself with one clean, unmistakable symptom.

It does not walk into the exam room wearing a name tag.

Instead, it shows up as a pattern.

Fatigue. Headaches. Brain fog. Muscle aches. Joint pain. Morning stiffness. Tingling. Numbness. Dizziness. Vertigo. Abdominal pain. Diarrhea. Blurred vision. Light sensitivity. Sleep disruption. Mood changes. Word-finding difficulty. Poor concentration.

The clinical definition describes it as a multi-system, multi-symptom illness. That phrase matters. It means the illness can affect multiple parts of the body at once, which is precisely why patients often bounce from one specialist to another.

A neurologist sees the tingling.

A rheumatologist sees the pain.

A gastroenterologist sees the diarrhea.

A psychiatrist may be asked to evaluate the anxiety, depression, or cognitive symptoms.

A primary care physician is left trying to connect the dots.

But the dots may not connect unless someone asks a simple environmental question:

Where are you spending your time?

Home. Work. School. Gym. Dorm. Church. Office.

Buildings matter.

For some patients, they matter more than we have been taught to believe.

What’s So Bad About a Little Mold?

People often ask, “Isn’t mold everywhere?”

Yes, it is.

Mold is part of the natural world. We encounter it outdoors. We breathe in small amounts of spores. Most people tolerate ordinary environmental exposure without developing a chronic inflammatory illness.

The problem is not simply that mold exists.

The problem is what can happen inside a water-damaged building.

When water intrusion affects manufactured building materials — such as gypsum board, engineered wood, insulation, or composite materials — microbial growth can begin within about 48 hours. But mold is only part of the story.

Water-damaged buildings can also contain bacteria, fungal fragments, microbial volatile organic compounds, building-related chemicals, endotoxins, beta-glucans, and ultrafine particulates. Together, these can create a complex inflammatory exposure.

One way to think about this is cigarette smoke.

If a guest smoked inside your home, how long would the smell linger?

Days? Weeks? Months?

Even after the cigarette is gone, particles and volatile compounds can remain in the air and settle into materials. The same basic concept helps explain why exposure from water-damaged buildings can be so difficult to recognize and remediate.

The particles involved can be extraordinarily small — far below what the naked eye can detect. In some cases, particulates produced by bacteria and fungi can be submicroscopic. That means a building can look normal, smell only faintly musty, and still contain an inflammatory exposure capable of activating the innate immune system in susceptible people.[3]

This is the part that patients often understand before their doctors do.

They know they feel worse in one building and better somewhere else.

They know they return from vacation with more energy, only to crash again after a few days at home or work.

They know something in their environment seems to be speaking to their immune system.

They just may not have the language for it yet.

What Can Be Found in Water-Damaged Buildings?

Research into water-damaged buildings has identified a wide range of toxins, inflammagens, microbes, and particulates, including:[3]

· Mycotoxins

· Bioaerosols

· Cell fragments

· Cell wall components

· Hyphal fragments

· Conidia

· Beta-glucans

· Mannans

· Spirocyclic drimanes

· Inorganic xenobiotics

· Gram-negative bacteria

· Gram-positive bacteria

· Actinomycetes

· Nocardia

· Mycobacteria

· Protozoa

· Chlamydia

· Mycoplasma

· Endotoxins

· Lipopolysaccharides

· Hemolysins

· Proteinases

· Chitinases

· Siderophores

· Microbial volatile organic compounds

· Building material volatile organic compounds

· Coarse particulates

· Fine particulates

· Nano-sized particulates

That is not “a little mold.”

That is a biological and chemical ecosystem.

And for a genetically susceptible patient, that ecosystem may be enough to keep the innate immune system in a state of chronic activation.

The Discovery of CIRS

The story of CIRS begins not in a major academic center, but with a small-town physician in Pocomoke, Maryland.

Dr. Ritchie Shoemaker had graduated from Duke University School of Medicine and started his own practice on Maryland’s Eastern Shore. In the fall of 1997, thousands of fish began dying in the Pocomoke River near his home and practice.

Soon, local residents began reporting a strange illness.

Aches. Pain. Fatigue. Brain fog. Memory problems. Diarrhea.

The usual medical workups were unrevealing. Standard therapies did not seem to help.

Then came the clinical observation that changed everything.

One of Dr. Shoemaker’s patients was suffering from diarrhea. To help relieve that symptom, he prescribed cholestyramine, an older cholesterol medication that binds bile in the gastrointestinal tract and prevents its reabsorption.

A few days later, the patient reported that her diarrhea had improved.

But so had everything else.

Her other symptoms had improved too.

That raised a fascinating question: how could a medication that is not systemically absorbed affect symptoms throughout the body?

Cholestyramine stays in the gut. It binds compounds in bile and helps carry them out through the stool. Dr. Shoemaker reasoned that if the medication was improving systemic symptoms, perhaps it was binding and removing some form of toxin being recycled through bile.[4]

Around the same time, fish kills in North Carolina had been linked to a dinoflagellate called Pfiesteria. Dr. Shoemaker’s collaboration with health officials in North Carolina helped advance the understanding of toxin-related illness from this organism.

His work later expanded to include blue-green algae, ciguatera, tick-borne infections, brown recluse spider bites, and eventually the most common exposure source among CIRS patients: water-damaged buildings.[5–7]

From a small medical practice near a river full of dying fish, a larger framework began to emerge.

Some patients were not simply tired.

They were inflamed.

Some were not simply anxious.

Their brains were affected.

Some were not imagining symptoms.

Their immune systems were reacting to something their clinicians had not yet learned to see.

Why This Matters

Steve’s story began with a question that many patients carry silently:

Why can’t I get better?

When symptoms cross multiple systems, when the usual tests are normal or incomplete, and when patients are given labels without a unifying explanation, it is easy for both patient and clinician to feel stuck.

CIRS offers one possible framework for a subset of these patients.

It is not the answer to every chronic illness.

It is not a diagnosis that should be made casually.

But it is a diagnosis worth understanding, especially in patients with multi-system symptoms, a history of water-damaged building exposure, and a pattern of chronic inflammation that does not fit neatly into conventional categories.

In Part Two, we will go deeper into the biology: how CIRS is diagnosed, what happens inside the immune system, and why some patients become trapped in an inflammatory loop long after the original exposure begins.

For now, the actionable step is simple:

Look around.

Think about the buildings where you spend the most time. Have there been leaks, floods, roof problems, musty odors, visible mold, damp basements, water stains, or HVAC issues? Do symptoms improve when you are away and return when you come back?

Sometimes the first clue is not found in a lab result.

Sometimes it is hiding in the walls.

References

1. Stephenson JB, F. C., Anderson KB, Crothers N, Howe B, Johnson RP, Sloss N, Solomon R, Choy L, Derr M, Feldesman A, Horner T, Liles A, Moy L, Rhodes-Kline A. (2008). GAO-08–980. United States Government Accountability Office: Indoor Mold: Better Coordination of Research on Health Effects and More Consistent Guidance Would Improve Federal Efforts. U. S. G. A. Office. Washington, DC, GAO.
2. Shoemaker RC. Differential Association of HLA DR by PCR Genotypes with Susceptibility to Chronic, Neurotoxin-Mediated Illnesses. Poster presentation, American Society for Tropical Medicine and Hygiene. 2002 Nov 15, Denver CO.
3. Shoemaker R, Mark L, McMahon S, Thrasher J, Grimes C. 2010. Policyholders of America. Research Committee Report on Diagnosis and Treatment of Chronic Inflammatory Response Syndrome Caused by Exposure to the Interior Environment of Water-Damaged Buildings.
4. Shoemaker R. Diagnosis of Pfiesteria-human illness syndrome. Maryland Medical Journal. 1997; 521–523.
5. Shoemaker R, House D. Cyanobacterial Harmful Algal Blooms: State of the Science and Research Needs; Characterization of chronic human illness associated with exposure to cyanobacterial harmful algal blooms predominated by Microcystis. Hudnell HK, editor. 2009:653.
6. Shoemaker R, House D, Ryan J. Defining the neurotoxin-derived illness chronic ciguatera using markers of chronic systemic inflammatory disturbances: A case/control study. Neurotoxicology and Teratology. 2010; 32:633–639.
7. Shoemaker R, Hudnell D. A time-series study of sick building syndrome: chronic, biotoxin-associated illness from exposure to water-damaged buildings. Neurotoxicology and Teratology. 2004; 1–18.