Correlation between clinical findings and results of autologous serum skin test in patients with chronic idiopathic urticaria

OBJECTIVES To investigate the correlation between the clinical characteristics of chronic idiopathic urticaria (CIU) and the results of autologous serum skin test (ASST). METHODS This prospective observational study was performed in the Motahari Allergy Clinic and included 69 patients referred to the clinic with a diagnosis of CIU. ASSTs were performed on all patients. We compared the disease characteristics, including duration severity, number of urticaria, and size of urticaria between those with positive and negative results of ASST. RESULTS Of 69 patients with CIU, 39 (56.5%) were female and 30 (43.5%) were male with a mean age of 32.5±12.3 (range 6-62) years. Patients with a positive ASST had a significantly higher number of wheals (P=0.043) with larger sizes (P=0.031). They also had higher frequencies of wheals (63.8% vs. 46.4% daily; P=0.039) and higher disease activity scores (1.57±0.9 vs. 2.01±1.6; P=0.044). The disease activity score was positively correlated with the size of the wheals, duration of the wheals, duration of the disease, and total number of wheals. Patients with positive ASST results had significantly higher frequencies of arthritis (P=0.027). CONCLUSION Positive ASST results are associated with more severe disease determined by the larger wheals' size, longer duration of the disease, and higher frequencies of the disease. As ASST reveals the autoimmune basis of the CIU, it can be concluded that CIU patients with autoimmune basis will suffer from more severe disease.