The Allergist

“You can have a patient that has normal immunoglobulins and abnormal responses to protein antigens as well. Historically, I’ve seen these patients. They do happen. They are out there.” — Dr. Benjamin Prince
Specific antibody deficiency (SAD) has never been a clean diagnosis. Some patients carry normal immunoglobulins and still land in clinic with recurrent infections and poor vaccine responses. The newer pneumococcal vaccines have scrambled the old testing pathways. This episode covers which parts of the workup still hold up, and where a titre should actually change what you do next.
Dr. Mariam Hanna is joined by Dr. Benjamin Prince, Associate Professor of Pediatrics and Associate Division Chief of Research in Allergy and Immunology at Nationwide Children's Hospital in Columbus, Ohio. He walks through the shifting definition of SAD, what pneumococcal titres can and can't tell you, and how to read testing in the Prevnar 20 era.
Key Points
Clinical history as the gatekeeper for who gets worked up
What Prevnar 20 did to polysaccharide response testing
Reading the patient ahead of the titre
Recommendation 4.7 and impaired protein-antigen responses
Pneumococcal titre thresholds: useful, imperfect, lab-dependent
The management range, from watchful waiting through immunoglobulin replacement
A useful listen for any clinician who has stared at a borderline pneumococcal panel and wondered whether to keep pulling the thread. The lab pathway exists, but the history is still what tells you whether the result will mean anything.

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The Allergist is produced for CSACI by PodCraft Productions

“If the asthma is under good control but they are still having these episodes, then I do think that maybe they have a PVFMD component to their breathing issue.” Dr. R. Jun Lin
Patients come into clinic short of breath. It hits during exercise, it looks dramatic, and they may even describe noisy breathing or the feeling that they “can’t get air in.” So we do what clinicians do: we think asthma. We try inhalers. But sometimes, no matter how many puffers are thrown at the problem, nothing changes.
That’s when it may be time to look higher, to the larynx.
On this episode of The Allergist, Dr. Mariam Hanna is joined by Dr. R. Jun Lin, a fellowship-trained laryngologist and chief of the Division of Laryngology at the University of Toronto, for a practical discussion of vocal cord dysfunction, inducible laryngeal obstruction, and paradoxical vocal fold motion disorder. Dr. Lin walks through how these patients present, how to distinguish laryngeal obstruction from asthma, when both may be present, and why respiratory retraining therapy is often the cornerstone of care.
Key Points
VCD, ILO, EILO, and PVFMD describe the same basic problem through different specialty lenses.
The key clue: trouble breathing in, not out.
In teens, it often shows up during warm-up or early competition.
In adults, common triggers include perfume, bleach, gasoline, cooking fumes, cold air, humidity, speaking, or laughing.
Asthma and PVFMD can coexist. If asthma is controlled but symptoms persist, think larynx.
Laryngoscopy is often normal in PVFMD, but helps rule out structural causes.
Respiratory retraining therapy is the cornerstone of treatment.
Pursed-lip breathing can reduce the severity and duration of episodes, but patients need to practise it before symptoms peak.
Food triggers, urticaria, tongue swelling, or rash point away from PVFMD.
Botox is a last resort, not first-line treatment.
For clinicians, this episode is a reminder that not every dramatic breathing episode starts in the lower airway. When the history points to trouble getting air in, especially with poor response to inhalers, PVFMD deserves a place on the differential.

Have an idea for the show or a comment, send us a text!
Visit the Canadian Society of Allergy and Clinical Immunology

Find an allergist using our helpful tool

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

The Allergist is produced for CSACI by PodCraft Productions

“AI might feel like magic at times, but mostly it's just powerful technology, and with any technology, it's a tool.” —Merlijn van Breugel
AI is no longer a future-tense possibility for allergists. It is already shaping diagnosis, prediction, documentation, patient communication, and the way clinicians think through complex decisions. But if AI can process more than we can, what still belongs to the clinician?
On this episode of The Allergist, Dr. Mariam Hanna is joined by Merlijn van Breugel, a data scientist and philosopher whose work focuses on AI in allergy and immunology. Together, they get into where AI may be most useful now and in the near future, including phenotyping asthma and eczema, supporting diagnosis in young children, combining genetic, environmental, wearable, and clinical data, and reducing the administrative work that pulls clinicians away from patient care. But the episode does not dodge the hard stuff: hallucinations, bias, validation, liability, overtrust, and the very human problem of changing behaviour in real clinics.
Key Points
Allergy and immunology are not early adopters of AI, partly because the field relies on complex, heterogeneous data.
AI is most promising when it helps reveal patterns clinicians struggle to synthesize on their own, such as asthma or eczema subtypes.
Large language models can hallucinate, so clinicians need to stay critical even when an answer sounds polished and convincing.
Decision-support tools should augment clinical judgment, not replace it.
Bias in training data can create real harm if AI tools work better for some patient populations than others.
The best use cases are significant, underserved problems where AI can do something that older tools could not.
AI literacy will become a core skill for clinicians who want to use these tools safely and effectively.
For allergists, the message is not to fear the machine or blindly follow it. AI may help identify patterns, reduce administrative work, and open new research possibilities, but the clinician still brings the judgment, context, accountability, and critical eye. The future is not AI instead of allergists. It is allergists who understand how to use AI well.
Have an idea for the show or a comment, send us a text!
Visit the Canadian Society of Allergy and Clinical Immunology

Find an allergist using our helpful tool

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

The Allergist is produced for CSACI by PodCraft Productions

“It’s a fun time to be a food allergist”—Dr. David Fleischer
Food allergy treatment is no longer just about avoidance, epinephrine, and hoping for the best. With high-dose OIT, low-dose OIT, SLIT, EPIT, Xolair, and other biologics entering the conversation, allergists now face a more practical question: what are we trying to achieve, and what approach best fits this patient and family?
On this episode, Dr. Mariam Hanna is joined by Dr. David Fleischer, section head of allergy and immunology and director of the Allergy and Immunology Center at Children’s Hospital Colorado, and professor of pediatrics at the University of Colorado School of Medicine. He walks through how dose, route, safety, family goals, practicality, and flexibility all shape the choice of therapy.
Key Points
Low-dose OIT may offer similar protection to higher-dose protocols in some patients, making the dose question more about goals, risk, and fit.
Protection is the first goal; clinical remission remains the harder, longer-term hope.
Lower-dose approaches may offer practical advantages, including fewer up-doses, fewer clinic visits, and potentially fewer side effects.
SLIT and EPIT may be useful options for families looking for more forgiving, lower-burden approaches.
Xolair can provide protection for selected patients, but Dr. Fleischer emphasizes that it is not disease-modifying.
Food allergy treatment is becoming a shared decision about efficacy, safety, practicality, and what the family actually wants from therapy.
With more tools in the food allergy toolbox, the future may not be one perfect protocol for everyone. It may be choosing the right therapy for the right patient, then having the flexibility to change course when life, goals, or tolerance change.

Have an idea for the show or a comment, send us a text!
Visit the Canadian Society of Allergy and Clinical Immunology

Find an allergist using our helpful tool

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

The Allergist is produced for CSACI by PodCraft Productions

“We need more than just random care. We need randomized care.” — Dr. Derek Chu
For years, the allergy world has been drowning in a sea of data—risk factors, prevention strategies, and enough diagnostic tools to fill a warehouse. But how do you translate 340 different risk factors into a cohesive plan when an anxious parent is sitting in your clinic demanding a skin test for their four-month-old?. On this episode, Dr. Mariam Hanna is joined by "systematic review genius" Dr. Derek Chu to unpack the evidence-based roadmap for food allergy and atopic dermatitis. It’s time to move past the "noise" and start reading between the lines of what our patients actually need.
Key Points:
Major vs. Minor Signals: Eczema severity and family history are the big players, while being first-born or male are merely minor notes in the risk profile.
The Diagnostic Trap: Testing only works if it changes practice; otherwise, you’re just putting a baby through the trauma of an itchy back for a 20% certainty bump.
De-escalating Momentum: Be skeptical of previous "avoid all nuts" labels; if the patient is already eating the food, do not skin test them to it.
The TITAN Initiative: We need national, high-quality food challenge capacity to provide the clarity that families are actually looking for.
Beyond Narrative Synthesis: The new eczema guidelines involve patients as partners and weigh everything from JAK inhibitors to the humble (but low-certainty) bleach bath.
Clean Hands, Frequent Moisture: Prevention of atopic dermatitis may be gray, but moisturizing with every diaper change—using clean hands—is a low-stakes win
Dr. Chu walks us through the "diagnostic momentum" that often leads clinicians to over-test and over-restrict, and why your Royal College exam cutoffs might not be as definitive as you remember. From the major and minor predictors of food allergy to the "multimorbid" patient with eczema, this conversation is a masterclass in being sensible and judicious at the bedside.

Have an idea for the show or a comment, send us a text!
Visit the Canadian Society of Allergy and Clinical Immunology

Find an allergist using our helpful tool

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

The Allergist is produced for CSACI by PodCraft Productions