Demographics and Comorbidities (Table 1)
From 2013 to 2021 we approached all patients presenting to the Montreal Children’s Hospital and the Children’s Clinic with CU. All patients approached consented to study participation. We recruited a total of 52 children with coldU. Approximately half of the patients (51.9%) were female and the median age at symptom onset was 9.5 years (interquartile range [IQR]: 4.8, 13.0).
Ice cube tests were performed in all patients and 90.4% of tests were positive. The remaining 9.6% of patients with negative tests had strong clinical histories consistent with coldU and were defined as atypical coldU. Importantly, no patients had clinical features or family histories indicative of cryopyrin-associated periodic syndromes orPLCG2 -associated antibody deficiency and immune dysregulation.
Triggers of coldU were recorded in 38 patients’ medical charts. Swimming was the most common trigger (76.3%), followed by cold weather/air (65.8%), and ingestion of cold food or drink (18.4%). Angioedema in addition to hives was documented in 28.8% of patients.
Other concomitant types of CU were recorded in 48.1% of patients, consisting of 22 (42.3%) with CSU and five (9.6%) with cholinergic urticaria (of which two patients had concomitant cholinergic urticaria and CSU). Comorbid atopic diseases included asthma (30.8%), atopic dermatitis (30.8%), allergic rhinitis (21.2%), food allergies (9.6%), and venom allergies (1.9%). Autoimmune diseases (celiac disease and type I diabetes mellitus) were documented in two (3.8%) patients.
A first-degree family history of atopy was present in 15.4% of patients. Moreover, a family history of CU was recorded in 17.3% of patients, a third of which was coldU.