Why Do Hives Look the Way They Do?

In this episode of the GA²LEN (Global Allergy and Asthma Excellence Network) Podcast on Everything Urticaria, Professor Torsten Zuberbier speaks with Professor Michihiro Hide from Hiroshima, Japan — a pioneer in urticaria research — about an unexpected connection between dermatology and mathematics.   The discuss: 🔹 Why do urticaria wheals form distinct shapes — round, annular, or geographic? 🔹 What controls how long a wheal lasts before fading? 🔹 Can mathematical formulas help explain the biology of hives? 🔹 What could this mean for diagnosis and treatment in the future? Professor Hide shares how a collaboration with a mathematician led to the creation of a computational model that simulates wheal formation in silico, revealing five recurring urticaria patterns that correspond to clinical types such as cholinergic or chronic spontaneous urticaria. Together, the two professors explore how mast cells, basophils, endothelial cells, and coagulation factors interact through feedback loops to create (and stop) a wheal — and how this model could reshape our understanding of urticaria’s pathophysiology and treatment.  Key Learnings from the Episode Urticaria’s shapes and lifespans can be mathematically modeled using Turing-inspired reaction-diffusion formulas. Five recurring patterns of wheals emerged from simulations, mirroring real-world urticaria morphology. Basophil-driven small dots (e.g., cholinergic urticaria) differ mechanistically from mast-cell-driven geographic wheals. Wheals persist longer than histamine-only reactions, implying sustained mast-cell activation. Urticaria develops through three stages — initiation, expansion, and resolution — governed by positive and negative feedback. Understanding the inhibitory phase that stops mast-cell activation is a key future research frontier. Mathematical modeling could help visualize and predict disease activity, opening paths for personalized therapy. Collaboration between clinicians and mathematicians may lead to a new diagnostic and research paradigm in chronic urticaria.  Chapters 00:00 Introduction to Urticaria Research 02:03 Exploring the Mechanisms of Urticaria 06:25 Mathematical Approaches to Urticaria 10:30 Patterns and Predictions in Urticaria 15:37 Understanding Treatment Responses 19:07 Future Directions in Urticaria Research Press releasehttps://www.eurekalert.org/news-releases/1009793 References1.    Seirin-Lee S, et al. A single reaction-diffusion equation for. the multifarious eruptions of urticaria. PLOS Computational Biology. 2020;16(1):e10075902.    Seirin-LeeS, et al. Mathematical-based morphological classification of skin eruptions corresponding to the pathophysiological state of chronic spontaneous urticaria.Communications Medicine. 2023;3(1):171.3.    Seirin-Lee S, et al. Pathophysiological Mechanisms of the Onset, Development, and Disappearance Phases of Skin Eruptions in Chronic Spontaneous Urticaria, Bulletin of Mathematical Biology. 2025; 87, 1Michihiro Hide has receivedlecture and/or consultation fees from Japan Tobacco, Kaken, Kyorin, KyowaKirin, Meiji Seiyaku, Mitsubishi Tanabe, Nippon Zoki, Novartis, Sanofi, Taiho,Teikoku and Yuhan.Do you have suggestions for future episodes? Please provide feedback and offer your suggestions for future topics and expert selection here.   Feedback form: ATU: ⁠⁠⁠⁠https://forms.office.com/e/m6a2uEdsUH