Clinical Characteristics, Management, and Natural History of Chronic Inducible Urticaria in a Pediatric Cohort.

Background Some forms of chronic urticaria (CU) can be specifically attributed to a response to a definite trigger, referred to as chronic inducible urticaria (CIndU). We aimed to assess the demographics, clinical characteristics, comorbidities, natural history, and management of pediatric patients with CIndU. Methods Over a 6-year period, children presenting to the allergy clinic at the Montreal Children's Hospital (MCH) with CIndU were prospectively recruited. CU was defined as the presence of wheals and/or angioedema, occurring for at least 6 weeks. A standardized diagnostic test was used to establish the presence of a specific form of urticaria. Resolution was defined as the absence of hives for 1 year without treatment. Results Sixty-four patients presented with CIndU, of which 51.6% were male, with a median age of 12.5 (interquartile range 7.3, 15.9) years. Cold CU and cholinergic CU were the most common subtypes (60.3 and 41.3%, respectively). Basophil counts were undetectable in 48.4% of the cases, and C-reactive protein levels were elevated in 7.8% of patients. Of all cases, 71.4% were controlled with second-generation antihistamines. The resolution rate was of 45.3% (95% confidence interval 33.1-57.5%), based on per-protocol population within the 6-year course of the study. Resolution was more likely in patients who presented with well-controlled urticaria control test scores and elevated CD63 counts and in those suffering from thyroid comorbidity. Conclusion The natural history of CIndU resolution in pediatric patients was relatively low and was associated with elevated CD63 levels, as well as thyroid comorbidity.