Chronic inducible urticaria subtypes in children: Clinical features and prognosis

Background Chronic inducible urticaria (CIndU) is a subtype of chronic urticaria induced by a physical stimulus. Objective To evaluate the clinical features, prognostic factors, and natural course of childhood CIndU subtypes. Methods Patients (1‐18 years old, n = 117) diagnosed with CIndU between March 2011 and March 2019 were analyzed. Patients (n = 101) were re‐evaluated for the status of their CIndU at least 6 months after the initial evaluation. Results The study population comprised of 117 children with a median (inter‐quartile range) age of 10.3 (6‐14.8) years at admission and a male predominance (53%). Symptomatic dermographism was the most common type of CIndU, affecting 65% of the group, followed by cold urticaria and cholinergic urticaria, which affected 17% and 15.4%, respectively. Baseline serum tryptase levels in cholinergic urticaria and cold urticaria were higher than those in symptomatic dermographism [7.0 (3.3‐10.7) μg/L, 4.2 (2.8‐9.3) μg/L, and 2.7 μg/L (1.8‐5.9), respectively; P = .020]. Recovery was observed in 9.6%, 25.3%, and 34.7% of the CIndU children after 12, 36, and 60 months, respectively. Of the patients with symptomatic dermographism, 40% had remission in 5 years, whereas this rate was only one‐fifth in patients with cold urticaria. The worst prognosis was observed in patients with cholinergic urticaria. Conclusion This study concluded that nearly one‐third of children with CIndU recovered within 5 years and symptomatic dermographism has the best prognosis. Cholinergic urticaria is the CIndU type with the worst prognosis, male dominance, and highest baseline serum tryptase levels.