Lower Serum SCCA2 Detectability in Chronic Spontaneous Compared with Chronic Inducible Urticaria: A Prospective Observational Study

Background/Objectives: Squamous cell carcinoma antigen 2 (SCCA2; SERPINB4) is an IL-4/IL-13-inducible epithelial serpin that can inhibit human mast-cell chymase, providing a potential link to mast-cell-mediated inflammation. To our knowledge, SCCA2 has not previously been studied in chronic urticaria; we hypothesized that circulating SCCA2 would differ among chronic spontaneous urticaria (CSU), chronic inducible urticaria (CIndU), and healthy controls.