Enrolment and Questionnaires
Children presenting with CU were consecutively recruited from 2013 to
2021 as part of our CU registry at the Montreal Children’s Hospital and
an affiliated pediatric allergy clinic. Written informed consent was
obtained from the parents and/or legal guardians of study participants,
and an assent form was obtained from children seven years and older.
This registry was approved by the Centre for Applied Ethics from the
McGill University Health Centre Research Ethics Board (REB 12-255 GEN,
June 3, 2013). ColdU was diagnosed based on clinical history and wheal
formation after five minutes of skin exposure to a plastic bag-wrapped
ice cube5. The diagnosis of coldU also included cases
with cold-induced symptoms (at least two episodes in history) in the
absence of reaction to the ice cube test (atypical coldU). Patients were
also assessed at study entry for concomitant CIndUs by clinical history
and/or provocation testing, as well as for concomitant CSU. Data on
coldU triggers were extracted from the patients’ medical charts.
At study entry, we administered a standardized questionnaire querying on
the patient’s demographics, symptoms, comorbidities, family history, and
management of their coldU. Beginning in 2018, participants completed the
Urticaria Control Test (UCT) at study entry. Patients recruited prior to
2018, whose urticaria had not resolved, completed the UCT at follow-up.
Children less than 12 years of age were permitted to complete the
questionnaire and UCT with the help of their guardians, a score of at
least 12 was considered well-controlled8.