CIRS is a proposed multisystem illness in which genetically susceptible people (about 25% by HLA type) fail to clear biotoxins from water-damaged buildings, driving chronic innate inflammation. The solid part: damp buildings cause illness across 112 of 114 epidemiological studies and mycotoxins are demonstrably toxic. The contested part: the diagnostic biomarker panel, urine mycotoxin testing and the 12-step Shoemaker treatment protocol come almost entirely from one research group, and toxicology bodies question the commercial testing.
Summary drafted from this entry’s sources; editorial review pending.
01Key questions
Is mold illness real?
Dampness and mold in buildings cause respiratory and systemic illness, an association backed by WHO guidelines and 112 of 114 epidemiological studies. Whether CIRS is a distinct, diagnosable syndrome is still contested.71
Is urine mycotoxin testing valid?
Not established. The American College of Medical Toxicology questioned its clinical validity in 2025, no validated reference ranges exist, and results may reflect dietary rather than tissue exposure.
How is CIRS diagnosed?
By the Shoemaker criteria: symptoms in at least 8 of 13 clusters, a visual contrast sensitivity deficit, HLA susceptibility genotyping and a biomarker panel covering MSH, TGF-beta1, C4a and MMP-9.66
Does the Shoemaker protocol work?
It is the only treatment with documented clinical efficacy in the literature, including small randomized trials for cholestyramine and transcriptomic normalization after VIP, but virtually all evidence comes from the Shoemaker group.125
What would change this rating?
Independent replication of the biomarker panel and the treatment protocol outside the Shoemaker group.
02Overview
Chronic Inflammatory Response Syndrome (CIRS) is a multisymptom, multisystem illness caused by dysregulation of the innate immune system following exposure to biotoxins — most commonly from water-damaged buildings (WDBs) containing mold, actinobacteria, and other microorganisms. It is not an IgE-mediated allergy. Instead, it reflects a failure of the innate immune system to clear biotoxins in genetically susceptible individuals (~25% of the population), leading to chronic systemic inflammation.
The condition was identified by Ritchie Shoemaker, MD in 1997 during a Pfiesteria outbreak in Maryland waterways, and later extended to mold-exposed patients. A 2024 literature review found that the Shoemaker Protocol — centered on cholestyramine, removal from exposure, and intranasal VIP — is the only treatment in the published literature with documented clinical efficacy for CIRS (Dooley et al., 2024; PMID: 39649915).
⚠️ Controversy Status: CIRS remains contested in mainstream medicine. Chang & Gershwin (2019) concluded the evidence does not support "toxic mold syndrome" as a diagnostic entity, and criticized commercial mycotoxin testing labs as lacking scientific credibility. The American College of Medical Toxicology (2025) issued a position statement questioning the validity of urine mycotoxin testing. Meanwhile, a growing body of peer-reviewed literature — including transcriptomic and neuroimaging studies — supports a reproducible immune dysregulation pattern. Apply the Source Evaluation Framework rigorously: separate what is well-established (damp buildings cause illness) from what remains debated (specific diagnostic markers, treatment protocols).
03The CIRS Disease Model
Core Mechanism
- Exposure → Inhalation of biotoxins (mycotoxins, bacterial endotoxins, actinobacterial cell wall components) from WDBs, or ingestion/exposure to marine biotoxins (ciguatera, Pfiesteria), tick-borne illness (Lyme), or cyanobacteria
- Genetic susceptibility → HLA DR/DQ haplotypes in ~25% of the population impair antigen presentation and biotoxin clearance
- Innate immune activation → Persistent elevation of inflammatory cytokines without adequate transition to adaptive immunity
- Multisystem injury → Neuroendocrine disruption, capillary hypoperfusion, mitochondrial dysfunction, neuroinflammation
Key Biomarkers (Shoemaker Panel)
| Biomarker | Direction | Significance |
|---|---|---|
| MSH (Melanocyte-Stimulating Hormone) | ↓ Low | Master regulator of neuroimmune function; low MSH drives hypothalamic dysfunction, ADH/ACTH dysregulation |
| TGF-β1 | ↑ Elevated | Profibrotic cytokine; tissue remodeling, immune suppression |
| MMP-9 | ↑ Elevated | Matrix metalloproteinase; tissue destruction, vascular leak |
| C4a | ↑ Elevated | Complement activation product; innate immune activation marker |
| VEGF | ↓ or fluctuating | Vascular endothelial growth factor; capillary hypoperfusion when low |
| ACTH/Cortisol | Dysregulated | HPA axis disruption |
| ADH/Osmolality | Dysregulated | Posterior pituitary dysfunction; frequent urination, thirst |
| VCS (Visual Contrast Sensitivity) | ↓ Impaired | Functional neurotoxicity screen; biotoxin effects on optic nerve |
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Symptom Clusters
CIRS diagnosis (Shoemaker criteria) requires symptoms in ≥8 of 13 clusters:
- Fatigue / lethargy
- Aches, cramps, unusual pain
- Weakness
- Memory / concentration (brain fog)
- Headache / light sensitivity
- Frequent urination / thirst (ADH dysregulation)
- Abdominal pain / diarrhea / nausea
- Joint pain / morning stiffness
- Mood swings / anxiety / depression
- Skin sensitivity / tingling / numbness
- Shortness of breath / sinus congestion
- Red eyes / blurred vision / tearing
- Night sweats / temperature dysregulation
McMahon (2017) demonstrated that combining symptom cluster screening (≥8/13) with VCS deficit yielded >95% diagnostic accuracy for CIRS-WDB, and up to 98.5% when combined with lab criteria.
04Mycotoxins: Mechanism of Injury
Major Mycotoxins from Water-Damaged Buildings
| Mycotoxin | Primary Producers | Mechanism of Toxicity |
|---|---|---|
| Ochratoxin A (OTA) | Aspergillus, Penicillium | Nephrotoxic, DNA damage, oxidative stress, protein synthesis inhibition |
| Aflatoxins (B1, B2, G1, G2) | Aspergillus flavus, A. parasiticus | Hepatocarcinogenic (IARC Group 1), DNA adducts, p53 mutation |
| Trichothecenes (macro) | Stachybotrys chartarum ("black mold") | Protein synthesis inhibition, neurotoxicity, immune suppression |
| Fumonisins | Fusarium | Sphingolipid disruption, neural tube defects, esophageal cancer |
| Zearalenone | Fusarium | Estrogenic endocrine disruption |
| Gliotoxin | Aspergillus fumigatus | Immunomodulatory, apoptosis of immune cells |
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Non-Fungal Triggers in WDBs
Critically, actinobacteria (e.g., Corynebacterium, Streptomyces) co-habit WDBs and produce potent inflammatory cell wall components (mycolic acids). Shoemaker et al. (2021) demonstrated that some CIRS patients have negative ERMI scores (no detectable mold DNA) but clear transcriptomic evidence of actinobacterial exposure — meaning mold-only testing misses a significant subset of environmentally triggered illness (Shoemaker et al., 2021; PMID: 39649915 ref 35).
05Diagnostic Approach
Stepwise Screening
- Exposure history → Water damage, visible mold, musty odor, known WDB occupation
- Symptom cluster screen → ≥8/13 clusters (95% sensitivity)
- VCS test → Online or in-office visual contrast sensitivity test (low-cost screen)
- HLA DR/DQ genotyping → Identifies genetic susceptibility haplotypes (~25% of population)
- Biomarker panel → MSH, TGF-β1, MMP-9, C4a, VEGF, ACTH/cortisol, ADH/osmolality
- Environmental testing → ERMI (Environmental Relative Moldiness Index) DNA-based dust analysis; HERTSMI-2 (simpler panel); consider actinobacterial testing when ERMI negative
- Advanced → NeuroQuant brain volumetric MRI (caudate atrophy, pallidum enlargement pattern); GENIE transcriptomic platform (ProgeneDx) for gene expression profiling
ERMI and HERTSMI-2
- ERMI — EPA-developed DNA-based assay using dust samples to quantify 36 mold species (MSQPCR). Scores >2 suggest elevated mold burden; >5 significant.
- HERTSMI-2 — Abbreviated 5-species panel (Aspergillus ochraceus, A. fumigatus, Penicillium chrysogenum, Stachybotrys chartarum, Wallemia sebi) developed for clinical decision-making. Scores >11 associated with CIRS risk.
- Limitation: Neither panel detects actinobacteria, which may be the primary trigger in some patients.
Contested Testing
- Urine mycotoxin testing (e.g., RealTime Labs, Great Plains) — Commercially popular but not independently validated. ACMT (2025) and Chang & Gershwin (2019) question clinical utility. Results may reflect dietary mycotoxin exposure rather than tissue burden. Use with caution and never as sole diagnostic criteria.
- Provoked urine testing — Even more contested; no standardized protocols or reference ranges.
06Treatment Approaches Studied
Doses in studies
The Shoemaker Protocol is a sequential, stepwise approach. Each step addresses a specific physiological abnormality and is monitored by biomarkers. Do not skip ahead.
| Step | Intervention | Target | Evidence |
|---|---|---|---|
| 1 | Remove from exposure | Eliminate ongoing biotoxin exposure | Critical; all other steps fail if exposure continues |
| 2 | Cholestyramine (CSM) or Colesevelam | Bile acid sequestrant binds biotoxins in enterohepatic circulation | 2 RCTs (Level II), multiple case series (PMID: 17010568) |
| 3 | Eradicate MARCoNS (Multiple Antibiotic Resistant Coagulase Negative Staphylococci) | Nasal biofilm infection; EDTA nasal spray ± rifampin/bactroban | Case series |
| 4 | Correct ADH/osmolality | Desmopressin if indicated | Clinical response |
| 5 | Correct elevated MMP-9 | Fish oil (omega-3), low-amylose diet | Biomarker normalization |
| 6 | Correct elevated C3a | — | Case series |
| 7 | Correct elevated C4a | Erythropoietin or ARB (losartan) | Case series |
| 8 | Correct VEGF | Corrected automatically with steps 1-7 | — |
| 9 | Androgen support | DHEA supplementation if low | Clinical |
| 10 | Correct antidiuretic hormone | Desmopressin if persistently abnormal | Clinical |
| 11 | Lower elevated leptin | Corrected with treatment | — |
| 12 | Intranasal VIP (Vasoactive Intestinal Peptide) | Final step; restores neuroimmune regulation, reverses brain atrophy | Open-label trials (Level IV); PMID: 24946038 |
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Cholestyramine — Primary Intervention
Mechanism: Bile acid sequestrant that binds biotoxins in the gut lumen, preventing enterohepatic recirculation and promoting fecal elimination.
Evidence: - 2 RCTs (Shoemaker, Level II): 8 patients and 13 patients respectively, both demonstrating significant symptom resolution and VCS improvement vs. placebo - Case-control study (n=156 cases, 110 controls): Statistically significant biomarker normalization - Limitation: All studies from Shoemaker group; independent replication is minimal
Binding Specificity: - ✓ Effective: Ochratoxin A, fumonisins, zearalenone - ✗ Weak binding: Aflatoxins, trichothecenes (including from Stachybotrys) - ✓ Colesevelam (Welchol) as alternative for patients intolerant to CSM
Side Effects: Constipation (most common), acid reflux, interference with fat-soluble vitamin absorption (A, D, E, K) and medication absorption.
2024 crossover trial: Cholestyramine 12 weeks reduced serum PFOS (perfluoroalkyl substance) by ~60%, demonstrating the bile-acid sequestration effect extends beyond mycotoxins to persistent organic pollutants (PMID: 38367552).
Intranasal VIP — Final Step
Mechanism: Vasoactive intestinal peptide; anti-inflammatory neuropeptide that regulates innate immunity, vascular tone, and neuroimmune function.
Evidence: - Ryan & Shoemaker (2016): RNA-Seq showed VIP therapy normalized transcriptomic profiles in 14 CIRS patients — suppressed inflammatory genes, restored ribosomal/mitochondrial gene expression (PMID: 25889530) - Shoemaker et al. (2017): Serial MRI (NeuroQuant) demonstrated significant volumetric increases in grey matter nuclei (hippocampus, caudate, thalamus, putamen, pallidum, cerebellum); proportion of structures with atrophy fell below 1% - Increased T regulatory cells (CD4+ CD25+) from 8.9% to 22.5% — indicating restoration of immunoregulatory function
Availability: Compounding pharmacy only; ~$300+/month; not insurance-covered.
Cautions: Must complete Steps 1–11 first; VIP in uncorrected patients can cause hypotension, flushing. Monitor blood pressure.
07Transcriptomic Advances (2015–2025)
The GENIE (Gene Expression: Inflammation Explained) platform uses Nanostring digital barcoding to profile gene expression, revealing a defining molecular hallmark of CIRS called molecular hypometabolism (MHM):
- Suppression of ribosomal and mitochondrial genes → impaired protein synthesis and cellular energy production
- Proliferative physiology → IRS2 upregulation shunts pyruvate from oxidative phosphorylation to aerobic glycolysis (Warburg-like), producing less ATP and more lactate
- Triple-positive fingerprint (TUBB1 + TUBA4A + CLU + coagulation genes) → detected in some CIRS patients; initially identified in Parkinson's disease; may represent an early, modifiable neurodegenerative risk signature
- Treatment trajectory → GENIE tracks a predictable sequence (suppression → overshoot → correction → stability) called the "CIRS curve"
A 2025 review by Dooley traced the evolution from VCS testing → proteomic biomarkers → neuroimaging (NeuroQuant) → transcriptomics, arguing that CIRS offers a more reproducible diagnostic model than ME/CFS, which lacks validated biomarkers (PMID: 40806417).
Post-COVID Connection
Shoemaker et al. (2021) applied GENIE profiling to Post-COVID Syndrome (PCS) patients and found overlapping transcriptomic signatures with CIRS-WDB: molecular hypometabolism, proliferative physiology, suppressed CD3D, and upregulated TGFBR1-3/CD14/TLR4. This raises the possibility that a subset of Long COVID patients may have CIRS-like immune dysregulation that is treatable.
08Evidence Summary and Skepticism
What Is Well-Established (Tier 1–2)
| Finding | Evidence Quality |
|---|---|
| Dampness and mold in buildings cause respiratory and systemic health effects | Strong — WHO guidelines (2009, PMID: 23785740); 112 of 114 epidemiological studies show association (Dooley & McMahon, 2020) |
| ~25% of the population has HLA haplotypes associated with impaired biotoxin clearance | Moderate — Consistent clinical observations; limited independent genetic validation |
| Mycotoxins (aflatoxin, ochratoxin, trichothecenes) are toxic to humans at sufficient exposure | Strong — IARC classifications, occupational health data |
| Cholestyramine binds certain mycotoxins in the GI tract | Moderate — Animal data + human pharmacology of bile acid sequestration |
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What Remains Contested (Tier 3–5)
| Claim | Evidence Quality |
|---|---|
| CIRS is a distinct, diagnosable clinical entity with reproducible biomarkers | Moderate — Primarily Shoemaker group publications; limited independent replication |
| Urine mycotoxin testing reflects tissue burden and guides treatment | Weak — Commercial labs; no validated reference ranges; dietary confounding |
| The Shoemaker 12-step protocol is the only effective treatment | Moderate — Best-documented in literature, but virtually all from one research group |
| VCS testing is a reliable screening tool for biotoxin illness | Moderate — Functional screen with clinical utility, but not specific to CIRS (other neuro-ophthalmic conditions cause VCS deficits) |
| Environmental ERMI scores reliably predict patient illness | Moderate — Association exists, but false negatives (actinobacteria) and false positives complicate clinical use |
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Key Skeptical References
- Chang & Gershwin (2019) — Independent critical review concluding that evidence does not support "toxic mold syndrome" as defined by Shoemaker; criticized commercial mycotoxin testing laboratories as lacking scientific credibility
- American College of Medical Toxicology (2025) — Position statement questioning clinical validity of urine mycotoxin testing
- Hurraß (2024) — German scientific medical societies mold guideline (updated 2024)
- Karhuvaara (2024) — Independent biomarker study with mixed findings
Assessment per Source Evaluation Framework: The epidemiology of damp-building health effects is solid (T4–T5: epidemiological + WHO/IARC consensus). The CIRS diagnostic framework is promising but not yet independently validated at scale (T2–T3: human biomarker signal primarily from one research group). Treatment evidence is Level IV–VI (case series, small RCTs) — meaningful for clinical practice but requiring independent replication.
09Practical Notes
For Clinicians
- Screen broadly: Any patient with medically unexplained multisystem symptoms (fatigue, cognitive issues, chronic pain, respiratory complaints, mood changes) living or working in a water-damaged building should be screened for CIRS
- Studies started with VCS + symptom clusters — low-cost, non-invasive
- Do not rely on urine mycotoxin testing alone — order the full Shoemaker biomarker panel through Quest/LabCorp
- Cholestyramine first — after confirmed exposure removal, CSM is the foundational intervention
- VIP is the last step — premature VIP use without correcting upstream steps can cause harm
For Patients
- Remediation first — No treatment protocol works if you continue living in the moldy environment. This often means professional remediation or relocation.
- ERMI/HERTSMI-2 — Dust-based testing gives a snapshot of cumulative mold burden; combine with visual inspection by certified inspector (IICRC)
- Patience — The full Shoemaker Protocol takes 6–18 months; premature skipping of steps leads to treatment failure
- Financial burden — CSM, labs, environmental testing, and especially VIP (compounded) create significant costs; insurance coverage is inconsistent
Cross-References in This library
- Stealth Pathogens — CIRS overlaps with chronic Lyme, cell-wall-deficient bacteria, and biofilm-mediated illness
- Lyme and Co-infections — Post-treatment Lyme disease syndrome shares transcriptomic signatures with CIRS
- Biofilms Overview — MARCoNS (nasal biofilm infection in CIRS) is a biofilm condition
- Biofilm Disruption Protocols — EDTA nasal spray for MARCoNS connects to broader biofilm disruption
- Mitochondrial Health — CIRS molecular hypometabolism is fundamentally a mitochondrial energy disorder
- NAD+ and Sirtuin Activators — NAD+ depletion is a common feature; mycotoxin load appears in the NAD+ fatigue differential
10Connections
11Sources
- Dooley M, Vukelic A, Jim L. Chronic inflammatory response syndrome: a review of the evidence of clinical efficacy of treatment. Ann Med Surg . 2024;86(12):7248. PMID: 39649915 . doi 10.1097/MS9.0000000000002718PubMed 39649915 · DOI 10.1097/MS9.0000000000002718
- Shoemaker RC, House DE. Sick building syndrome and exposure to water-damaged buildings: time series study, clinical trial and mechanisms. Neurotoxicol Teratol . 2006;28:573–588. PMID: 17010568 . doi 10.1016/j.ntt.2006.07.003PubMed 17010568 · DOI 10.1016/j.ntt.2006.07.003
- Shoemaker RC, House D, Ryan JC. Structural brain abnormalities in patients with inflammatory illness acquired following exposure to water-damaged buildings. Neurotoxicol Teratol . 2014;45:18–26. PMID: 24946038 . doi 10.1016/j.ntt.2014.06.004PubMed 24946038 · DOI 10.1016/j.ntt.2014.06.004
- PubMed 38367552PubMed 38367552
- Ryan JC, Wu Q, Shoemaker RC. Transcriptomic signatures in whole blood of patients with CIRS following exposure to ciguatoxin. BMC Med Genom . 2015;8:15. PMID: 25889530 . doi 10.1186/s12920-015-0089-xPubMed 25889530 · DOI 10.1186/s12920-015-0089-x
- Dooley M. Biomarkers over Time: From Visual Contrast Sensitivity to Transcriptomics in Differentiating CIRS and ME/CFS. Int J Mol Sci . 2025;26(15):7284. PMID: 40806417 . doi 10.3390/ijms26157284PubMed 40806417 · DOI 10.3390/ijms26157284
- WHO. Guidelines for Indoor Air Quality: Dampness and Mould. 2009. PMID: 23785740 .PubMed 23785740
- Shoemaker RC, Katz D, Ackerly M, et al. Intranasal VIP safely restores volume to multiple grey matter nuclei in patients with CIRS. Intern Med Rev . 2017;3:1–14. doi 10.18103/imr.v3i4.412DOI 10.18103/imr.v3i4.412
12Entry history
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Heretic informs and never prescribes. Where amounts appear, they describe what published studies used. Talk to a qualified clinician before acting on anything here.