Epidemiological Study Of 655 Patients With Chronic Urticaria And Detection Of Food Specific IgG,IgG4 Antibodies From Their Sera

Objective:To survey clinical epidemiologic profiles and detect concentration of serum food-specific IgG (sIgG) and IgG4 (sIgG4) antibodies in 655 patients with chronic urticaria (CU) from Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University. To analyze the correlation of the levels of sIgG or sIgG4 with the disease severity of CU and evaluate the clinical outcome of dietary avoidance based on IgG or IgG4 against food.Methods:We retrospectively investigated the clinical features of 655 patients with CU. ELISA was used in all patients to detect the concentration of food-specific immunoglobulins against 20 kinds of food. Weekly Urticaria Activity Score (UAS7), Dermatology Life Quality Index (DLQI) and oral antihistamine usage were evaluated by questionnaire for 65 patients and were reevaluated at the end of 6 months.Results:In our patients, the prevalence was significantly lower in men than in women with male/female ratio 1:2. The age ranged from 14 to 87 years.35.5% of patients CU lasted more than 1 year. Other allergic skin diseases were reported by 8.1% of cases. The mean Weekly Urticaria Activity Score (UAS7) in 65 patients with CU was 22.55 (range 2-42). The mean Dermatology Life Quality Index was 7.32 (range 0-22). Loratadin and cetirizine were the most frequently used medicines. The total positive rate of food sIgG and sIgG4 were significantly higher in CU patients than in controls (74.4%,69.3% vs 13.3%,6.7%). Egg, peanut, milk, soya bean and crab were the most common offending food. There were no correlations among levels of sIgG or sIgG4 and UAS7, DLQI or oral histamine usage. Furthermore, food restriction did not improve the clinical parameters.Conclusions:CU is more common in middle aged women. The duration of the disease in some of the patients is more than 1 year. The affect of CU on quality of life is moderate. Hl antihistamines can effectively control symptoms. Other allergic skin diseases are less prevalent in patients with CU. The total positive rate of food sIgG and sIgG4 were significantly higher in CU patients than in controls. Egg, peanut, milk, soya bean and crab were the most common offending food. But detection of food specific IgG and IgG4 maybe not helpful for etiologic diagnosis and for evaluation of the severity of CU. Food restriction based on sIgG and sIgG4 may not be a useful strategy in the management of CU.