What Is CIRS Disease? Causes, Symptoms, and Treatment

Chronic Inflammatory Response Syndrome, or CIRS, is an acquired condition in which the innate immune system gets stuck in a loop of chronic inflammation after exposure to certain biological toxins, most commonly from water-damaged buildings. It is not a single-organ disease but a multisystem illness that can produce dozens of seemingly unrelated symptoms, from crushing fatigue and cognitive fog to joint pain and shortness of breath. Because no single specialty “owns” these symptoms, CIRS has been called an under-recognized and underdiagnosed condition, with some researchers estimating that up to a quarter of the population carries the genetic vulnerability to develop it.

What Triggers CIRS

The most thoroughly studied trigger is prolonged exposure to the indoor environment of a water-damaged building. When a building takes on water through a leaky roof, flooding, or chronic condensation, the damp materials become a breeding ground for a complex mix of biological agents. This is not just about “mold.” The illness appears to result from a combination of factors present in these environments, including mold spores and fragments, mycotoxins (toxic chemicals produced by certain molds), bacteria, bacterial endotoxins, and other cell wall components.¹ It is the stew of contaminants, not any single species, that seems to drive the inflammatory cascade. Research assessing illness in people exposed to visibly colonized water-damaged buildings has supported a link between exposure and multisystem symptoms, though investigators have noted that more work is needed to tease apart which components of that mixture are most responsible.²

Other biotoxin sources have been implicated as well. Certain tick-borne infections, exposure to cyanobacteria (blue-green algae) in contaminated water, and contact with specific reef fish toxins can all, in theory, set off the same inflammatory chain. Water-damaged buildings remain the best-documented and most common route by a wide margin, though, and the research literature overwhelmingly focuses on this exposure.

Why Some People Get Sick and Others Don’t

One of the most frustrating aspects of CIRS for patients is the social dynamic: you feel devastated, but your coworker who sits ten feet away in the same water-damaged office is fine. The leading explanation involves genetic variation in the human leukocyte antigen (HLA) system, specifically certain HLA-DR and HLA-DQ gene types. These genes help your immune system recognize and clear foreign substances. Certain HLA-DR/DQ alleles have been linked to mycotoxin susceptibility because individuals carrying them appear to be poor eliminators of mycotoxins from their systems.³

In practical terms, this means the immune system in a genetically susceptible person never properly tags and removes the biotoxin. Instead, the toxin continues circulating and re-stimulating the innate immune system, creating a self-perpetuating cycle of inflammation that persists even after the person leaves the contaminated building. Case reports have documented patients carrying what researchers call a “multisusceptible haplotype,” a genetic profile associated with developing chronic inflammation across multiple biotoxin exposure types, who show highly elevated inflammatory markers alongside critically low levels of protective neuropeptides.⁴ People without these susceptible gene types are generally able to clear the toxins before the cycle takes hold.

Symptoms Across Multiple Systems

CIRS rarely looks the same from one patient to the next, which is a big part of why it gets missed. The condition simultaneously affects multiple organ systems, so a given patient might present with neurological complaints, respiratory issues, gastrointestinal symptoms, and musculoskeletal pain all at once.⁵ Common complaints include:

Fatigue: Not ordinary tiredness but a deep, unrelenting exhaustion that does not resolve with rest.
Cognitive dysfunction: Often described as “brain fog,” including trouble concentrating, difficulty finding words, and short-term memory lapses.
Pain: Headaches, joint aches, muscle cramps, and unusual nerve-type pain like tingling or ice-pick sensations.
Respiratory symptoms: Chronic cough, shortness of breath, sinus congestion, and recurring respiratory infections.
Gastrointestinal issues: Abdominal pain, diarrhea, appetite changes, and nausea.
Sensitivity reactions: Increased sensitivity to bright light, new chemical sensitivities, and a feeling of static shocks.
Mood and sleep disruption: Anxiety, depression-like symptoms, night sweats, and difficulty regulating body temperature.

A person walking into a primary care office with fatigue, brain fog, sinus congestion, and joint pain will very likely be evaluated for conditions like fibromyalgia, depression, or chronic fatigue syndrome. Without the environmental exposure history and lab work specific to CIRS, the underlying driver is easy to miss entirely.

How CIRS Affects the Brain

The neurological dimension of CIRS deserves its own discussion because it often dominates the patient’s experience and because measurable structural changes have been documented. A volumetric MRI study comparing CIRS patients to healthy controls found statistically significant differences in brain structure, including atrophy of the caudate nucleus and enlargement of the pallidum. The left amygdala and right forebrain were also enlarged in patients. More than 45% of CIRS cases showed gliotic areas on MRI, compared with roughly 5% of controls. Spectroscopy findings included elevated lactate and depressed ratios of glutamate to glutamine.⁶ The researchers proposed a model in which chronic systemic inflammation increases permeability of the blood-brain barrier, allowing inflammatory molecules to reach and damage brain tissue. For patients, this may explain why the cognitive and neurological symptoms can feel so severe and so out of proportion to what shows up on standard neurological exams.

Biomarkers and How CIRS Is Diagnosed

There is no single blood test that says “CIRS.” Diagnosis relies on a pattern of clinical findings, exposure history, and a panel of lab abnormalities. In CIRS patients, there is typically a reduction in regulatory neuropeptides, especially melanocyte-stimulating hormone (MSH), and an elevation in at least one of three inflammatory markers: TGF-beta-1, C4a, and MMP-9.⁵ Beyond those core abnormalities, clinical data from large case series have documented a broader constellation of measurable findings in confirmed cases. In a cohort of over 1,800 patients, deficiency of the regulatory neuropeptide vasoactive intestinal peptide (VIP) occurred in 98%, alongside MSH deficiency, elevated TGF-beta-1, abnormal complement activation (C4a), dysregulated stress hormones, abnormal vascular growth factor levels, and coagulation disturbances.⁷

Another diagnostic tool is visual contrast sensitivity (VCS) testing, a non-invasive screening in which a person looks at patterns of gray lines and reports which ones they can distinguish. Studies have consistently shown that biotoxin-exposed individuals have reduced contrast sensitivity compared with non-exposed controls across multiple testing formats.⁸ VCS is not specific to CIRS alone, but a failed test in someone with a compatible exposure history and symptoms adds another piece to the diagnostic puzzle. It is often used as an inexpensive initial screen before ordering the full biomarker panel.

A nasal swab for MARCoNS (Multiple Antibiotic Resistant Coagulase Negative Staphylococci) is another standard part of the workup. MARCoNS is a biofilm-forming, toxin-producing staphylococcal bacterium that colonizes the deep nasal passages of roughly 80% of confirmed adult CIRS cases, compared with only 1-2% of healthy controls.⁹ MARCoNS colonization can contribute to fatigue and neurological symptoms like peripheral neuropathy and headaches, and it needs to be addressed as part of treatment. The distinction matters: ordinary coagulase-negative staph in the nose is a neutral colonizer and does not need treatment, while MARCoNS specifically shows resistance to penicillin and at least one other antibiotic class.

The Shoemaker Protocol

Treatment for CIRS follows a sequential, step-by-step approach most commonly known as the Shoemaker Protocol, named after the physician who developed it. A literature review examining published treatments for CIRS found that this was the only protocol with documented clinical efficacy, described in 11 of 13 articles reviewed.⁵ The protocol is designed to be followed in a specific order, with each step building on the one before it.

The first and arguably most important step is removing the patient from the source of exposure. No amount of medication will resolve the inflammatory cycle if the person continues breathing in biotoxins every day. For many patients, this means professional remediation of their home or, in some cases, leaving it entirely. After removal from exposure, treatment typically begins with cholestyramine (CSM), a bile-acid-binding resin originally used to lower cholesterol. In CIRS patients, it is used to bind biotoxins in the gut and prevent them from being reabsorbed. The MARCoNS eradication step follows, usually involving a topical nasal spray.

Subsequent steps address the specific biomarker abnormalities identified in each patient, correcting hormonal imbalances, reducing elevated inflammatory markers, and eventually restoring the depleted regulatory neuropeptides. The final step in refractory cases involves replacement doses of VIP delivered as a nasal spray. In an open-label trial of 20 patients who had not fully responded to earlier steps, VIP safely reduced symptoms to control levels, corrected inflammatory parameters, raised VIP and MSH levels, normalized exercise-induced pulmonary artery pressures, and enhanced quality of life, with durable responses lasting up to 18 months without significant side effects.⁷ Transcriptomic analysis of patients treated with VIP showed shifts in immune gene expression, including downregulation of innate immune functions and metabolic changes consistent with a calming of the inflammatory response.¹⁰

Remediation of the Building Itself

Treating the patient without fixing the building is a recipe for relapse. This is where things get complicated, because there are no federal safety standards in the United States specifically governing occupancy of buildings with a history of water intrusion. Existing remediation guidelines have traditionally focused on building-health parameters such as correcting envelope defects, removing microbial growth, and discarding contaminated materials, without incorporating human-health outcomes into the success criteria. A 2020 consensus statement from an expert panel sought to expand on existing professional society recommendations by including guidelines for remediating buildings to be reoccupied by previously sickened patients.¹¹

For you as a homeowner or tenant, this means that standard mold remediation may not be enough. A typical remediation company will remove visible mold and dry out the affected area, which addresses the building’s structural problem but may not reduce the airborne particulate and mycotoxin load to levels safe for a CIRS-susceptible person. Patients are generally advised to work with indoor environmental professionals familiar with CIRS-specific remediation standards, including post-remediation testing that goes beyond visual inspection.

CIRS Versus Chronic Fatigue Syndrome

One of the most significant diagnostic overlaps is between CIRS and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Both conditions produce debilitating fatigue, cognitive dysfunction, and immune dysregulation, and they share molecular patterns including mitochondrial impairment and vascular dysfunction.¹² The practical consequence is that some patients carrying an ME/CFS diagnosis may actually have unrecognized CIRS, a distinction that matters because the treatment pathways diverge sharply. The same review noted that ME/CFS research has yet to establish a unified diagnostic model with validated biomarkers or exposure-linked mechanisms, while CIRS has a defined biomarker panel and a documented treatment protocol.

If you have been diagnosed with ME/CFS and your symptoms began after a move, a renovation, a flood, or work in a water-damaged building, it is worth asking whether a CIRS evaluation has been considered. The biomarker panel, VCS screening, and HLA testing can help clarify the picture. This is not to suggest that all ME/CFS is actually CIRS; ME/CFS is a real and distinct condition. But the overlap is substantial enough that ruling out CIRS in patients with a suggestive exposure history could change their treatment trajectory.

CIRS in Children

CIRS is not limited to adults. A large clinical series examined 1,722 children, ranging from 7 months to 18 years old with an average age of about 4.5 years, who had been diagnosed with both autism spectrum disorder and CIRS. About 78% were male. When these children were treated with established CIRS protocols, researchers observed notable improvements in cognition, motor skills, respiratory health, skin conditions, gastrointestinal function, and speech and language.¹³ This is a developing area of research and should be interpreted carefully; a clinical series does not prove causation, and the relationship between ASD and biotoxin exposure is not established at the level of randomized trials. Still, for parents of children with both environmental exposure histories and multisystem symptoms, awareness that pediatric CIRS exists and can be evaluated is important.

Children may be harder to diagnose because they cannot always articulate their symptoms. A child with CIRS might present as having behavioral problems, learning difficulties, frequent infections, or chronic abdominal pain, all of which have long differential diagnosis lists. As with adults, the exposure history is a critical clue. A child who developed new symptoms after the family moved into an older home or after a basement flood warrants a closer look.

The Recognition Problem

Despite a growing body of published research, CIRS remains outside the mainstream of most medical practice. The majority of primary care physicians and even many specialists are unfamiliar with the condition, its biomarker panel, or its treatment protocol. Patients frequently describe seeing five, ten, or more physicians before encountering one who considers CIRS. Part of the difficulty is structural: the condition does not fit neatly into any single specialty. Rheumatologists see the joint pain, pulmonologists see the shortness of breath, neurologists see the cognitive complaints, and gastroenterologists see the gut symptoms. Each specialist may evaluate and treat their piece of the puzzle without recognizing the common inflammatory thread running through all of it.

The evidence base itself also has characteristics that invite skepticism in academic medicine. Much of the foundational research originates from a relatively small group of investigators, and several key studies are open-label case series rather than randomized controlled trials. The literature review that examined treatment efficacy found only 13 articles addressing CIRS treatment, with 11 describing the Shoemaker Protocol.⁵ That concentration around a single protocol and a small research community does not invalidate the findings, but it does mean that independent replication by outside groups remains limited. Patients should be aware of this landscape: the published data shows real, measurable improvement in biomarkers and symptoms with treatment, but the condition awaits the kind of large-scale, multi-center validation that would shift it from “emerging” to “established” in the eyes of mainstream medicine.

For people navigating this space right now, the practical path forward usually involves finding a physician who is trained in the CIRS protocol, getting the full biomarker panel drawn, and, if the results are consistent with the diagnosis, following the sequential treatment steps while simultaneously addressing the environmental exposure. Online directories maintained by CIRS-focused medical organizations can help locate trained practitioners, though availability varies significantly by region. If you live in a water-damaged building and your symptoms are worsening, getting out of that environment is the single most impactful step you can take while sorting out the rest of the diagnostic and treatment process.