Etiology of Chronic Urticaria in Latin America, Ecuadorian experience.

RATIONALE: The purpose of this study was to identify chronic urticaria (CU) etiologies and treatment modalities in Ecuador. We propose that the sample distribution fits the expected one, and that there is an association between the etiology and its treatment.

METHODS: We performed a retrospective study involving 112 patients diagnosed with CU. Demographic and clinical variables were collected. The etiology of CU was classified using the EAACI/GA2LEN/EDF/WAO guideline. Descriptive analyses were performed for demographical and clinical variables. Chi square tests were applied to analyze the fit of distribution and the independence of variables. P values less than 0.05 were considered significant.

RESULTS: Among all the patients, 76.8% were diagnosed with chronic spontaneous urticaria (CSU), of which 22.3% had a known etiology, being food associated urticaria the most common (10.7%) (p<0.01). On the other hand, 23.2% inducible urticarias (CIndU) were indetified, where dermographism was the most common (10.7%) (p<0.01).

Regarding treatment regimens, sg-H1-antihistamines alone represented the highest proportion prescribe (44.6%). The combination of any H1-antihistamine plus other drug was a close second (42.0%) (p<0.01). Almost 48% of CSUs of unknown etiology were treated with any antihistamine plus another drug. In patients with known etiology, sg-H1-antihistamines alone (44.0%) was the most common management. In addition, 53.8% of CIndUs were treated with sg-antihistamines alone. Though, these associations were not statistically significant.

CONCLUSIONS: CSU is the most frequent subtype of CU. Modern non-sedating antihistamines in licensed doses are the drug of choice. Nevertheless, a great proportion of patients require the addition of another type of medication.