A small study found that people with chronic spontaneous hives have lower blood levels of the immune peptide LL‑37, and the lower the level, the worse their symptoms. The research shows a link but doesn’t test any treatment or give dosing advice.

Chronic spontaneous urticaria (CSU) is a significant clinical condition characterized by an undetermined etiology, with some of its manifestations being attributed to immunological factors. The antibacterial properties of the cathelicidin leucine-leucine-37 (LL-37) can potentially contribute to the development of autoimmune disorders. Evaluating serum level of cathelicidin in CSU, particularly in its autoimmune aspect, will provide novel insights into pathogenesis. This study assessed serum cathelicidin levels in CSU patients and determined the association between serum cathelicidin and urticaria activity score (UAS). This case-control study involved 40 CSU patients and 40 sex and age-matched controls. Total IgE, serum cathelicidin levels, and antithyroid antibodies were measured. An autologous serum skin test was done, and the UAS was assessed. The levels of LL-37 exhibited a statistically significant difference between the investigated groups, with downregulated levels observed in the case group. A statistically significant negative association exists between the urticaria severity index and serum cathelicidin. Additionally, we detected a statistically insignificant correlation between serum cathelicidin and age, disease duration, hemoglobin, white blood cells, eosinophils, total IgE, antithyroglobulin antibody, and antithyroid peroxidase antibody. A significant association was also detected between urticaria severity and serum cathelicidin. In conclusion, LL-37 level contributes to many autoimmune diseases, and recent studies have pointed to its role in allergic diseases. CSU is a critical skin disease and needs more research to identify the triggers to open the gate for new treatment.