Artificially separating the body from the mind has been one of the biggest missteps of modern medicine. Over the last few years, we have increasingly read studies confirming the mind-body connection, the gut-brain axis, and now we are learning more about the nose-brain connection.

Given the direct proximity between our nose and our brain, this connection shouldn’t be much of a surprise. The olfactory nerve, cranial nerve 1, wires directly to the amygdala, hippocampus, and orbitofrontal cortex – our emotional centers. Smells, our most ancient sense phylogenetically, have been a critical part of our ability to sense threats, perceive rewards, and maintain homeostasis.

Over the years, within the field of allergy/immunology, we have anecdotally noticed the toll that living with chronic congestion, nasal obstruction, loss of smell and taste, and headaches takes on our patients. Missed work, foggy thinking, and interrupted sleep all take their toll. With allergies affecting between 10 to 30 percent of U.S. adults and costing upwards of $3 to 4 billion per year, allergic rhinoconjunctivitis has a profound impact on society. Studies have long confirmed our suspicions that anxiety and depression occur at higher rates among allergic patients, and we see a similar phenomenon in autoimmune conditions like lupus, rheumatoid arthritis, and Sjogren’s disease.

For years, allergists have pondered the question: which comes first? Does the chronic symptom burden cause mental health symptoms? Is it an alteration in sleep quality? Is it something driven by another pathophysiologic mechanism? Do these patients share genetic quirks that predispose them to both?

As with most things in medicine, it isn’t straightforward, but recently published studies have demonstrated that high levels of inflammatory mediators such as IL-1beta, IL-6, and TNF alpha can penetrate the blood-brain barrier and activate major brain regions regulating emotions, including those in the limbic system.

We also know that the hypothalamic pituitary adrenal (HPA) axis plays a significant role in the connection between our brain, hormones, and inflammation responses. The HPA axis plays a role in the generation of anxiety and depression in patients with chronic inflammation, including allergies. Allergic inflammation results in the production of excess glucocorticoids, which play a role in mood regulation in the hippocampus and limbic systems. Over time, this can result in hormone resistance and further dysregulation.

Not only can we see effects on our emotions, but we can also see changes in thinking speed, memory, and learning related to allergies as well. Additionally, some of the medications commonly used to treat allergies can compound this effect, such as 1st generation antihistamines, also known as “Benadryl brain”! This is why allergists are increasingly vocal about encouraging the use of second-generation antihistamines that have much lower anticholinergic side effects and do not cross the blood-brain barrier as readily.

I am frequently asked how one can “boost” or “balance” their immune system, and this begs the question: What can we do?

1. Severity of allergies correlates directly with increased rates of anxiety and depression. It is reasonable to postulate that treating symptoms before they get out of hand may lessen this risk. Allergen avoidance, intranasal corticosteroids, long-acting second-generation antihistamines, and allergen immunotherapy are the mainstays of allergy treatment.

2. Optimize other factors that increase the risk of allergies, anxiety, and depression, including sleep routines, nutrition, and exercise! Aiming for 7 to 9 hours of quality sleep, eating a diverse plant-forward diet, and getting 150 minutes of moderate activity weekly are all beneficial for our immune system health.

3. Increasingly, data supports the avoidance of substances that impair our epithelial barriers to prevent the development of allergic and autoimmune conditions, including harsh soaps and surfactants, indoor and outdoor air pollution, dishwasher rinse aids, and certain food additives.

With longer growing seasons, we are seeing record-high pollen counts again this year. Safe and effective treatment strategies are available that can significantly improve our quality of life in ways that we may not have even realized before.

Kara Wada is a quadruple board-certified pediatric and adult allergy and immunology, lifestyle, and functional medicine physician, a Sjögren’s disease specialist, and a Sjögren’s patient herself. She spent nine years on faculty at The Ohio State University Wexner Medical Center, where she served as associate program director of the allergy and immunology fellowship and led the Mast Cell Center of Excellence.

In 2025, she left academic medicine to build the kind of practice she could not find as a patient: the Immune Confident Institute, a national direct-care immunology practice licensed in 27 states. She treats the patients the health care system sends ping-ponging between specialists, people with complex, chronic, multisystem disease including mast cell activation syndrome (MCAS), dysautonomia, Sjögren’s disease, immune dysfunction, and the seronegative and “in-between” diagnoses that do not fit neatly into a single specialty.

Her premise is simple: These patients are not the problem. Fragmented care is. Medicine has become exceptionally good at looking through microscopes while losing sight of the telescope, the bigger picture of the person in front of us. Her work challenges a health care culture that demands compliance when it should assume competence, and aims to make strategic, compassionate immune-directed care the standard, and the exam room a place where patients are finally seen, heard, and believed.

Most of her reach is built outside the exam room. Her YouTube channel drew roughly two million views this past year, and more than 100,000 people follow her work across platforms, including a Sjögren’s community of about 6,600. She founded and hosts the Virtual Sjögren’s Summit, now in its sixth year and drawing some 4,300 registrants worldwide. She appears regularly on national television and in the health press, including Prevention, SELF, Good Housekeeping, WebMD, Medscape, and MedPage Today, and she writes for KevinMD on the diagnoses that live in the shadows and the medical gaslighting that surrounds them.

A TEDx speaker and sought-after keynote, Wada speaks to clinician and patient audiences about complex immune disease, the experience of being disbelieved, and what changes when the physician is also the patient. She is also an unlikely pageant titleholder, having served as Dr. Ohio America 2022 and Dr. Midwest America 2023, and has written about how pageantry sharpened skills medicine rewards but rarely teaches.

She earned her medical degree with honors from the University of Illinois College of Medicine at Peoria and completed internal medicine-pediatrics residency, allergy and immunology fellowship, and clinician educator fellowship at The Ohio State University and Nationwide Children’s Hospital. She lives in Columbus, Ohio, with her medical school sweetheart turned husband, Akira, and their three children.