CH50 as a Clinically Useful Biomarker of Disease Activity and Antihistamine Resistance in Chronic Spontaneous Urticaria: An Observational Ambispective Single‐Center Study. - Planella‐Fontanillas, Nidia; Berna‐Rico, Emilio; Pesqué, David; Andrades, Evelyn; Sánchez, Silvia; Torres‐Bosó, Paloma; Gimeno, Ramon; Gallardo, Fernando; Pujol, Ramon M.; Giménez‐Arnau, Ana M. (International Journal of Dermatology, 2026)