Could an "iceberg" forming quietly beneath the surface for years be the real reason your immune system suddenly turned against you? Dr. Tania Dempsey joins us to unpack two conditions that are far more connected and common than most people realize: Mast Cell Activation Syndrome (MCAS) and Toxicant-Induced Loss of Tolerance (TILT). Dr. Dempsey walks us through how a susceptible person can quietly become a sensitive one, and how a single trigger event, whether it's mold, infection, chemical exposure, or trauma, can push a body to its tipping point. From symptoms that can affect nearly every system in the body to the frustrating cycle of being bounced between specialists without answers, she explains what it takes to identify the true root cause, even when your labs come back "normal." Dr. Dempsey also shares practical screening tools, treatment strategies, and real patient stories of recovery that offer hope for those still searching for answers. Tune in to learn why your immune system may be trying to protect you, not betray you, and what steps may help you begin moving toward recovery. Episode Highlights · What is toxicant-induced loss of tolerance (TILT), and how does it relate to mast cell activation syndrome (MCAS)? (3:12) · How does the "iceberg" image help us understand TILT, and how does a susceptible person become a sensitive, symptomatic one? (10:21) · Why can MCAS and TILT symptoms show up in nearly every system of the body? (14:48) · How common are MCAS and TILT, and why might the numbers be higher than official estimates? (19:05) · What are the BREESI and QEESI screening tools, and how do doctors use them to assess TILT? (21:32) · Why is identifying triggers the essential first step in treatment? (24:53) · What does a typical patient workup with Dr. Dempsey actually involve? (28:14) · What happens to the body after a mold or chemical trigger is removed? (31:46) · What are mast cell stabilizers, and how do they help calm an overactive immune system? (36:00) · How can patients who suspect they have MCAS or TILT advocate for themselves with their doctor? (37:52) · What patient success stories offer hope for people still searching for a diagnosis? (44:41) Links mentioned in interview: The Surprising Science Behind Indoor Chemistry With Dr. Charles Weschler: https://changetheairfoundation.org/the-surprising-science-behind-indoor-chemistry/ TILT & MCS Uncovered: The Science Behind Chemical Intolerance With Dr Shahir Masri: https://changetheairfoundation.org/tilt-mcs-uncovered-the-science-behind-chemical-intolerance/ TILT Research Program for Chemical Intolerance: https://tiltresearch.org/ Chemical Intolerance Self-Assessment (QEESI): https://tiltresearch.org/self-assessment/ Quick Environmental Exposure and Sensitivity Inventory (QEESI): https://tiltresearch.org/wp-content/uploads/sites/231/2024/06/qeesi.pdf Brief Environmental Exposure and Sensitivity Inventory (BREESI): https://aseq-ehaq.ca/wp-content/uploads/2021/08/BREESI.pdf TILT and MCS Assessment Tools: https://hsph.harvard.edu/research/hoffman-program/resources/chemicals-in-your-life/assessment-tools/ International Society for Mast Cell Activation Syndromes: https://ismcas.org Rincón, R., Perales, R., Palmer, R. F., & et al. (2024). Environmental house calls can reduce symptoms of chemical intolerance: A demonstration of personalized exposure medicine. Primary Health Care Research & Development, 25, Article e53: https://www.cambridge.org/core/journals/primary-health-care-research-and-development/article/environmental-house-calls-can-reduce-symptoms-of-chemical-intolerance-a-demonstration-of-personalized-exposure-medicine/3CD1DD6B0B485730672A377A3A50BA3B Palmer, R. F., Dempsey, T. T., & Afrin, L. B. (2023). Chemical intolerance and mast cell activation: A suspicious synchronicity. Journal of Xenobiotics, 13(4), 704–718: https://pmc.ncbi.nlm.nih.gov/articles/PMC10660865/ Miller, C. S., Palmer, R. F., Dempsey, T. T., Ashford, N. A., & Afrin, L. B. (2021). Mast cell activation may explain many cases of chemical intolerance. Environmental Sciences Europe, 33, Article 129: https://doi.org/10.1186/s12302-021-00570-3 Miller, C. S., Palmer, R. F., Kattari, D., Masri, S., Ashford, N. A., Rincon, R., Perales, R., Grimes, C., & Sundblad, D. R. (2023). What initiates chemical intolerance? Findings from a large population-based survey of U.S. adults. Environmental Sciences Europe, 35, Article 65: https://doi.org/10.1186/s12302-023-00772-x Masri, S., Miller, C. S., Palmer, R. F., & Ashford, N. A. (2021). Toxicant-induced loss of tolerance for chemicals, foods, and drugs: Assessing patterns of exposure behind a global phenomenon. Environmental Sciences Europe, 33(1), Article 65. https://www.researchgate.net/publication/351924396_Toxicant-induced_loss_of_tolerance_for_chemicals_foods_and_drugs_assessing_patterns_of_exposure_behind_a_global_phenomenon Get in touch with our guest: Dr. Dempsey’s Website: https://drtaniadempsey.com Facebook: https://www.facebook.com/taniadempseymd Instagram: @drtaniadempseymd Learn more about Change the Air Foundation: https://ChangeTheAirFoundation.org Sign up for our newsletter: https://ChangeTheAirFoundation.org/stay-informed/ Disclaimer: Your Indoor Air Podcast, a Change the Air Foundation production, is for general informational purposes only and does not constitute the practice of medicine, nursing, healthcare or other professional services, such as giving healthcare advice. The use of information on this podcast or materials linked from this podcast is at the user’s own risk. The content of this podcast is not intended to be a substitute for professional medical care. Users should not disregard or delay in seeking medical attention for any medical condition or concern they may have.
