Study validates quick screening for chemical intolerance, finds one in five affected

close-up roller with inlays and drops of white paint used to show possible chemical exposure.

Contact: Steven Lee, 210-450-3823,

SAN ANTONIO – A recent study validates use of a brief questionnaire to screen patients for chemical intolerance, after a large national sampling, and the researchers conclude the condition likely affects one in five people.

Previously, researchers at The University of Texas Health Science Center at San Antonio, also known as UT Health San Antonio, developed a 50-question instrument that has become the international reference standard for research and diagnosis of chemical intolerance. It is known as the Quick Environmental Exposure and Sensitivity Inventory (QEESI).

But they since devised a three-question version, the Brief Environmental Exposure and Sensitivity Inventory (BREESI), now validated by the new study as an effective initial screening tool, with a sample of 10,000 U.S. residents who took both surveys. The finding means that doctors now have an even quicker way of identifying possible chemical intolerance, which has been linked to a range of debilitating illnesses.

“The three-item BREESI makes it possible to assess chemical intolerance rapidly and with a fairly high degree of confidence and should, when warranted, prompt a more comprehensive assessment using the QEESI,” said Raymond F. Palmer, PhD and professor in family and community medicine at UT Health San Antonio. “So, we recommend: Screen with the BREESI, confirm with the QEESI.”

The findings were published this summer in the International Journal of Environmental Research and Public Health. Dr. Palmer is an author, along with Claudia S. Miller, MD, professor emeritus in the family and community medicine division at UT Health San Antonio; Carlos Roberto Jaén, MD, PhD, FAAFP, chair of the division; and division specialists Tatjana Walker, Rudy Rincon and Roger B. Perales. They are joined by principals of Hayward Score, a California healthy-home research and assessment organization.

An under-appreciated driver

Chemical intolerance is characterized by multi-system symptoms triggered by low levels of exposure to certain chemicals, foods and food additives, and drugs and medications. Those symptoms can include allergic-like reactions, some very severe, and indicating specific illnesses or conditions.

“It is an under-appreciated driver of those conditions among patients who might not know how to report their symptoms to their doctors or on health questionnaires,” said Dr. Miller, the study’s senior author who first identified a disease process called toxicant-induced loss of tolerance, or TILT, to explain a link between common chemicals and so-called unexplained illnesses, from her background as an allergist, immunologist and environmental scientist.

“Health care professionals routinely ask about a history of adverse reactions to latex or antibiotics,” she said. “Similarly, we urge practitioners, medical practices and health plans to adopt the BREESI in order to screen their patients for chemical intolerance.”

From people responding to both questionnaires in the new study, the researchers noticed that the predicted probability of chemical intolerance increased sharply with each increase in the number of BREESI items endorsed. They calculated the overall prevalence of chemical intolerance in the sample at just more than 20%.

“Despite the prevalence of chemical intolerance, clinicians or researchers might not have diagnosed or identified it because they haven’t known the pertinent questions to ask – until now,” said Dr. Jaén. “They might have missed important opportunities to understand chemical intolerance as it relates to other conditions.”

Here is the three-question BREESI:

1. Do you feel sick when you are exposed to tobacco smoke, certain fragrances, nail polish/remover, engine exhaust, gasoline, air fresheners, pesticides, paint/thinner, fresh tar/asphalt, cleaning supplies, new carpet or furnishings? By sick, we mean: headache, difficulty thinking, difficulty breathing, weakness, dizziness, upset stomach, etc.

2. Are you unable to tolerate or do you have adverse or allergic reactions to any drugs or medications (such as antibiotics, anesthetics, pain relievers, X-ray contrast dye, vaccines or birth control pills), or to an implant, prosthesis, contraceptive chemical or device, or other medical/surgical/dental material or procedure?

3. Are you unable to tolerate or do you have adverse reactions to any foods such as dairy products, wheat, corn, eggs, caffeine, alcoholic beverages or food additives (e.g., MSG, food dye)?

If “yes” to any of these questions, go to to find a link to download the QEESI and for more information.

The new study was funded by the nonprofit Marilyn Brachman Hoffman Foundation, which supports education, outreach and research on TILT at UT Health San Antonio. The Hayward Score principals include Carl Grimes, healthy home director; Dana Sundblad, chief operating officer; and David Kattari, data scientist.

Go here to read a report on a paper published earlier this year by UT Health San Antonio researchers and others on TILT, a link between common chemicals and “unexplained” chronic illnesses.

Validation of a Brief Screening Instrument for Chemical Intolerance in a Large U.S. National Sample

Raymond F. Palmer, Tatjana Walker, David Kattari, Rudy Rincon, Roger B. Perales, Carlos R. Jaén, Carl Grimes, Dana R. Sundblad and Claudia S. Miller.

First published: Aug. 18, 2021, International Journal of Environmental Research and Public Health


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