IL21 and Pruritus: Our findings demonstrated a significant association between the proportion of Th17 cells and the levels if IL‐17, IL‐21, and TGF‐β1 in CSU patients with pruritus intensity, disease severity, and quality of life, while the proportion of peripheral blood Treg cells and serum IL‐35 level exhibited a negative correlation with pruritus intensity, disease severity, and quality of life.