"We use thresholds every day without even thinking about it. When we do a food challenge in our office, whether we know it or not, we're relying on the fact that there is a threshold for every patient. Some are going to be on the first dose, some are going to be at the last. And that's just part of what a threshold is." 

– Dr. Doug Mack

Food allergies aren’t one-size-fits-all, but we don’t talk enough about thresholds—the amount of an allergen it actually takes to trigger a reaction. Should every patient be following the same strict avoidance rules? Or should we be aiming for something more precise?

To help us make sense of thresholds, we welcome back Dr. Douglas Mack, pediatric allergist, clinical immunologist, and Vice President of CSACI. Dr. Mack is known for his work on food allergy treatment, including oral immunotherapy, epinephrine use, and—you guessed it—thresholds.

On this episode, Dr. Mack and Dr. Mariam Hanna dig into:

• What a threshold actually is and why it matters in clinical practice – How thresholds shape food challenges, oral immunotherapy, and allergen risk assessments, even when we don’t explicitly discuss them.
• How much allergen is too much? – Why two patients with the same allergy can have vastly different tolerance levels, and why strict avoidance isn’t always the best approach.
• Eliciting dose, cumulative dose, and the numbers that matter most – How clinical trials define reaction thresholds, and how allergists can use these data points to guide patient care.
• Real-world factors that affect thresholds – How co-factors like exercise, illness, sleep deprivation, and even hot showers can shift a patient’s threshold and increase reaction risk.
• Precautionary labels, airplane bans, and the science behind food allergy risk in everyday life – What research tells us about trace exposures, why precautionary labeling varies worldwide, and how allergists can help patients navigate the gray areas of food safety.

Thresholds aren’t just theoretical—they impact how we advise patients, assess risk, and tailor treatments. Dr. Mack walks us through the science behind these numbers and how allergists can apply them in daily practice.

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Find Dr. Hanna on X, previously Twitter, @PedsAllergyDoc or CSACI @CSACI_ca

The Allergist is produced for CSACI by PodCraft Productions