Cold Urticaria. Characterizing the population from an urticaria outpatient clinic

Cold Urticaria (ColdU) is a type of chronic inducible urticaria (CIndU) where recurrent pruritic wheals and/or angioedema occur after exposure to cold stimulus. Although it usually only affects exposed areas, systemic reactions can occur in severe cases. In this study, we seek to characterize the ColdU cases within our Centre's population of patients.

Retrospective study based on clinical files of patients diagnosed with ColdU followed in an urticaria outpatient clinic in Portugal prior to October 2020.

We included 52 patients total (40 women) with median age of 35 years, 19 patients with symptom onset before 18 years-old. ColdU was classified as acquired in all patients. Cold provocation tests were negative in 9 patients and these were classified as atypical ColdU. No significant differences were found between those with pediatric or adult onset of disease. Most of the patients had a localized form of the disease (52%). Despite not being statistically significant, it was found that patient's temperature threshold, assessed with TempTest® 4.0, was higher and stimulation time was shorter in more severe groups. All patients were treated with non-sedating antihistamines (daily or on-demand), finding that those controlled with standard dosages had lower temperature thresholds than those needing higher dosages (p < 0.01). One patient was under treatment with omalizumab.

ColdU is an heterogenous disease that can have life-threatening event consequences. Cold provocation tests and threshold assessment can be an important tool in the management treatment and in identifying severity groups.