Skin & Psych: The Surprising Link Between the Skin and Brain in AD and Beyond

In the latest episode of Skin & Psych, host Patricia M. Delgado, DNP, AGPCNP, DCNP, PMHNP, welcomed board-certified dermatologist and itch expert Matthew Zirwas, MD, for a wide-ranging discussion on atopic dermatitis (AD), psychodermatology, patient communication, and the evolving understanding of chronic inflammatory skin disease.

Zirwas reflected on the curiosity that has shaped his career, emphasizing the importance of continually asking “why” when evaluating both research and patient care. Drawing from years of experience in patch testing and inflammatory dermatoses, he challenged several long-held assumptions in dermatology, particularly the concept that AD is primarily an inherited disorder. Instead, he proposed that many cases may represent an “acquired” barrier dysfunction driven by modern environmental exposures, including air pollution, hard water, frequent bathing, and chemical exposures. According to Zirwas, these factors may contribute to epigenetic changes that impair the skin barrier and promote immune dysregulation.

The conversation also explored the overlap between AD and allergic contact dermatitis. Zirwas suggested that contact dermatitis may sometimes be overdiagnosed in patients whose underlying disease is actually environmentally triggered AD. He described seeing patients improve dramatically with biologic therapy despite incomplete allergen avoidance, reinforcing his belief that acquired barrier dysfunction plays a larger role than previously appreciated.

A major focus of the episode centered on psychodermatology and chronic itch management. Zirwas discussed his use of mirtazapine for nocturnal pruritus, highlighting its antihistaminic properties and relatively favorable safety profile compared with older sedating agents such as hydroxyzine or diphenhydramine. He noted that lower doses may be more effective for itch and sleep because antihistamine activity peaks around 15 mg, while higher doses exert more activating antidepressant effects. He also stressed the importance of framing these medications appropriately for patients to reduce stigma surrounding antidepressants and improve adherence overall.

Throughout the discussion, Zirwas emphasized the value of communication, empathy, and patient-centered education. He encouraged clinicians to remain intellectually curious, question dogma, and consider the broader psychosocial and environmental factors contributing to inflammatory skin disease. He also shared some recommendations for dermatology education resources, including his podcast, Derms on Drugs, online platforms like Vumedi and Scholars in Medicine, and other collaborative learning tools for trainees and practicing clinicians alike.

Click here to catch up on all episodes of the Skin & Psych podcast series, in collaboration with Psychiatric Times.