Introduction
Urticaria is a common phenomenon that affects 15-25% of the population at least once in a lifetime. While most episodes are acute1,2, a minority are prolonged, hence termed chronic urticaria (CU). CU is defined as recurrent urticarial lesions, appearing most of the days of the week, for at least 6 weeks.2-4The prevalence of CU in adults is estimated to be 1.8%, affecting women more than men and with up to 50% remission rate within one to three years.5 In adults, autoimmune or auto-allergy mechanisms are suggested as possible etiologies for CU. In most patients, no underline cause is found or can be proven, and the urticaria is termed chronic spontaneous urticaria (CSU).6
The literature regarding the characteristics and underlining mechanisms of CSU in children is limited.2,5,7-14 It is estimated that its prevalence in children is 0.1-0.3%15-18 with an equal distribution between genders, except among adolescents.5,13 However, a recent review demonstrated 1.1–1.5% prevalence of CU in children.19 The remission rate of CSU in children after one year is reported to be low (16.5% - 37%).2,5,18
A few small studies demonstrated an association between pediatric CSU and atopic diseases, including asthma, allergic rhinitis (AR), atopic dermatitis (AD) and food allergy.5,8-10 An overall, coexisting prevalence of 30% to 50% has been described.5,10,13 Chansakulporn et al. followed a small group of 92 patients and reported that one-third of the children with CU had atopic diseases, with an unusually high prevalence of food allergy (15.2%).5 Netchiporouk et al. reported that 28% of 139 children with CSU had atopy, but they did not distinguish between the different types of atopic diseases and age groups.9 In addition to atopic diseases, autoimmune diseases, including thyroid diseases, celiac and systemic lupus erythematosus (SLE) were also found to be associated with CU in children.20,21,22
The aim of the current study was to describe the demographics, clinical characteristics, comorbidities, and outcomes of a large pediatric cohort with CSU.