Overview and Burden of Chronic Spontaneous Urticaria

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EP: 1.Overview and Burden of Chronic Spontaneous Urticaria

EP: 2.Diagnosis, Severity, and Impact of Chronic Spontaneous Urticaria

EP: 3.Chronic Spontaneous Urticaria Management and the Role of Patient Communication

EP: 4.Chronic Spontaneous Urticaria: Diagnosis and Treatment Strategies

Jane Mast, PhD, DMSc, MPAS, PA-C: Hello, and welcome to this Dermatology Times Partner Perspectives video series on chronic spontaneous urticaria, or CSU. My name is Jane Mast, I'm a Novartis Medical Director of Dermatology and Allergy, and joining me today is Dr Jonathan Rodrigues, also a Novartis Medical Director of Dermatology and Allergy but a formally practicing board-certified allergist. Thanks so much for being here.

Jonathan Rodrigues, MD: Thank you, Jane.

Jane Mast, PhD, DMSc, MPAS, PA-C: In this series, we will discuss best practices for the assessment, diagnosis, and management of CSU. Before we get to those topics, let's talk about the disease itself and how our understanding of it has evolved. We will begin with an overview of CSU. Can you talk about the clinical features of the disease?

Jonathan Rodrigues, MD: CSU is characterized with the presence of wheals and/or angioedema for a period of greater than 6 weeks.^1-3 Wheals, or hives, are sharply circumscribed superficial central swellings that may be accompanied by itching or burning, or both, and can be surrounded by reflex erythema.^1-3 Individual hives usually last somewhere between 30 minutes to 24 hours,^1-3 and that is important to note because if an individual hive lasts for more than 24 hours, we should consider the diagnosis of urticarial vasculitis.¹

Angioedema is a repeated occurrence of deep dermal or subcutaneous or submucosal swelling and can be accompanied by numbness, burning, tingling, or even pain rather than itching.^1-3 Angioedema too can affect any part of the body but commonly affects the lips, eyes, cheeks, or extremities.² Angioedema can take longer for resolution and can even take up to 72 hours to resolve.¹

33% to 67% of patients have an overlap of wheals and angioedema. 29% to 65% of patients can present with wheals alone, but it is important to note that 1% to 13% of patients can present with just angioedema.⁴

Jane Mast, PhD, DMSc, MPAS, PA-C: What kind of trends do we see in CSU as terms of prevalence and duration?

Jonathan Rodrigues, MD: CSU usually presents in patients between 30 to 50 years of age.² Women, unfortunately, are affected twice as often as men.² We see in literature that it is quoted that CSU lasts about 5 years, but CSU can last longer than 5 years, especially in more severe cases.⁵ About 50% of CSU patients can have ongoing symptoms despite the use of standard doses of antihistamine.^4,6 CSU is considered recurrent if it recurs after a period of 6 months of remission.⁷

Jane Mast, PhD, DMSc, MPAS, PA-C: Let's take a closer look at the mechanisms of CSU. What is important to know about the pathophysiology of CSU?

Jonathan Rodrigues, MD: The pathogenesis of CSU involves antibody-mediated mast cell and/or basophil activation and degranulation.⁸
Many mechanisms are involved in the pathogenesis of CSU, and although the exact mechanism is unknown, one possible mechanism is type I and type IIb autoimmune responses that involve IgE and IgG convergence on the surface of mast cells and basophils at the Fc epsilon receptor 1, otherwise known as a high-affinity IgE receptor.⁸ BTK is a key mediator in the signaling pathway that leads to mast cell degranulation and histamine release, driving CSU pathophysiology and causing symptoms such as itch, redness, hives, and swelling.^8-10

Jane Mast, PhD, DMSc, MPAS, PA-C: What is BTK and what role does it play in the pathophysiology of CSU?

Jonathan Rodrigues, MD: BTK, or Bruton's tyrosine kinase, is a member of the TEC family of kinases.¹¹ It mediates high-affinity IgE receptor 1 signaling in mast cells and basophils.¹¹ It also integrates B-cell receptor signaling to mediate B- cell development.¹¹

Jane Mast, PhD, DMSc, MPAS, PA-C: Thank you so much, Jonathan. This has been such an informative discussion on chronic spontaneous urticaria, and thank you to all our viewers for watching.

References
1. Zuberbier T et al. Allergy. 2022;77(3):734-766.
2. Saini SS. Immunol Allergy Clin North Am. 2014;34:33-52.
3. Kanani A et al. Allergy Asthma Clin Immunol. 2018;14(suppl 2):59.
4. Maurer M et al. Allergy. 2011;66(3):317-330.
5. Maurer M et al. Allergy. 2017;72(12):2005-2016
6. Kaplan AP. Allergy Asthma Immunol Res. 2017;9(6):477-482.
7. Toubi E et al. J Dermatol. 2021;48(11):1786-1788.
8. Mendes-Bastos P et al. Allergy. 2022;77:2355-2366.
9. Schocket AL. Allergy Asthma Proc. 2006;27:90-95.
10. Greaves M. J Allergy Clin Immunol. 2000;105:664-672.
11. Zarrin AA et al. Nat Rev Drug Discov. 2021;20(1):39-63.