Chronic Inflammatory Response Syndrome (CIRS) Explained

Chronic Inflammatory Response Syndrome (CIRS) is a multi-system illness thought to be triggered by biotoxins — from mold, Lyme, and other sources — in people whose immune systems don't clear those toxins effectively. The result is a persistent, dysregulated inflammatory response that can drag on for months or years after the exposure ends.

Because CIRS touches so many systems at once, it's often mistaken for other conditions or dismissed as stress, aging, or anxiety.

What CIRS looks like

CIRS is defined by a cluster of symptoms across many systems rather than one clear symptom:

• Fatigue, weakness, and brain fog
• Memory and concentration problems
• Muscle cramps, joint pain, and morning stiffness
• Sinus and respiratory issues
• Light sensitivity and visual contrast changes
• Temperature dysregulation and night sweats
• Gastrointestinal issues and new food sensitivities
• Mood symptoms: anxiety, irritability, depression
• Tingling, numbness, and frequent urination

Few patients have all of these, but most have a cluster that worsened after a specific exposure event. (See also mold toxicity symptoms for the overlapping pattern.)

The role of biotoxins

The leading theory is that genetically susceptible people exposed to water-damaged buildings or tick-borne infections fail to clear the inflammatory triggers most people eliminate without issue. The immune response, meant to be short-lived, instead becomes chronic — driving the wide-ranging symptom set above.

Common biotoxin triggers include:

• Mold and mycotoxins from water-damaged buildings (the most common)
• Lyme disease and co-infections like Bartonella
• Cyanobacteria and dinoflagellate toxins from marine or freshwater exposure
• Tick-borne and spider-borne toxins

Why some people get CIRS and others don't

Not everyone exposed to a water-damaged building gets CIRS. A key factor is the HLA-DR immune response gene: certain variants impair the body's ability to tag and clear biotoxins. In those people, the toxins persist, the inflammatory response never shuts off, and symptoms accumulate. This genetic susceptibility is why two people in the same moldy home can have very different outcomes.

How CIRS is assessed

CIRS is a clinical diagnosis — no single test confirms it. A typical workup combines:

• A symptom and exposure history (the symptom cluster and a known exposure)
• Visual contrast sensitivity (VCS) screening — a reduced score is a recognized marker
• Lab markers of inflammation and immune dysregulation (VIP, MMP-9, TGF-beta-1, C4a, MSH, and others)
• HLA genotyping to assess susceptibility
• Environmental assessment of where exposure is happening

A free VCS test is a reasonable first step: it's quick, objective, and noninvasive, and a deficit — alongside the right symptoms — is a signal worth taking to a clinician.

Where VCS fits into CIRS screening

Visual contrast sensitivity is one of the screening markers clinicians use because neurotoxin exposure reliably reduces retinal capillary blood flow, lowering contrast sensitivity even when acuity is normal. It's not diagnostic on its own, but it's:

• Cheap, quick, and repeatable
• Objective — a number you can track, not just a feeling
• Responsive to treatment — often recovers as the biotoxin load drops

That makes VCS useful both for initial screening and for monitoring recovery over time. (Learn how the test works.)

CIRS treatment in broad strokes

CIRS protocols generally move through phases:

1. Remove the exposure — remediate the building or remove yourself from it.
2. Bind and clear toxins — binders (cholestyramine, Welchol) help some people excrete biotoxins.
3. Address downstream inflammation — treat markers like MMP-9, MARCoNS, and hormonal disruption.
4. Rehabilitate — restore sleep, exercise tolerance, and cognitive function as inflammation settles.

Treatment should be clinician-guided; CIRS is complex and self-treating rarely goes well.

Frequently asked questions

Is CIRS the same as mold toxicity? They overlap heavily. Mold is the most common trigger of CIRS, but CIRS can also be triggered by Lyme and other biotoxins. "Mold toxicity" is the broader term people use colloquially; "CIRS" is the clinical framework that organizes diagnosis and treatment.

Can CIRS be cured? Many people improve substantially with exposure removal and treatment, and some recover fully. Relapse is common if exposure recurs, so environmental control is central.

Do I need a VCS test to diagnose CIRS? No single test diagnoses CIRS, but a VCS deficit is a recognized screening marker. Combined with symptoms, labs, and exposure history, it helps build the case. Take the free VCS test as a starting point.

Is CIRS recognized by mainstream medicine? CIRS is a clinical framework championed by some clinicians and researchers and debated by others. Regardless of the label, the symptom cluster and the value of removing exposure are widely accepted.

To start mapping your own symptom patterns, you can also try an online symptom assessment for mold and biotoxin exposure alongside your VCS screen. See our biotoxin resources for more.