Abstract: Objective: To determine the correlation between serum IL-31 levels and itching severity in the patients with chronic spontaneous urticaria. Methods: The level of IL-31 in 61  patients with chronic spontaneous urticaria and 59 healthy controls was detected by ELISA. The itching severity was assessed by visual analogue scale. Results: The average serum level of IL-31 in the patients was 28.63±15.38 pg/mL, which was higher than those in the healthy controls (1.74±0.30 pg/mL), with a significant difference (P<0.001). The average serum levels of IL-31 in the patients with mild, moderate and sever itching were 7.82±14.77 pg/mL, 34.28±10.39 pg/mL and 37.68±15.18 pg/mL respectively. The differences among the groups were significant (P<0.05). Conclusion: The itching severity in the patients with chronic spontaneous urticaria may be associated with the increasing level of IL-31.

Key words: chronic spontaneous urticaria, interleukin-31, pruritus