Evaluation of the Inhibitory Effect of 5 Anti-Histamines in Urticaria

Each patient will be assigned to receive the standard dose of one antihistamine for one month. The assignment of each patient group for each antihistamine will be using a double-blind system.

In the second month, patients who do not achieve good control, will receive a quadrupled dose of the same antihistamine received in the first month.

A medical evaluation, symptoms scales (UAS and DLQI) and prick test with histamine will be performed at enrollment and during the first and second months of follow up.

Safety and tolerability were assessed by adverse events reported by subjects at each postrandomization clinic visit. We did electrocardiogram and laboratory examination before initiation of antihistamine therapy and each month after (complete blood count [CBC], aspartate aminotransferase [AST], alanine aminotransferase [ALT], creatinine, blood urea nitrogen). We did an specific questionnaire (in spanish) to assess sedation:

"¿Sientes más sueño o somnolencia de lo acostumbrado?" (Do you feel more sleepy or drowsy than usual?), "¿Sientes que el sueño o la somnolencia interfiere con tus actividades diarias?" (Do you feel sleep or sleepiness interferes with your daily activities?), "¿Sientes que tú sueño no es reparador?" (Do you feel that you sleep is not restful?). Each question could be answered from 0 to 3 points (0 no 1. little, 2 moderate, 3 much). the sum of points defined them the severity of sedation in mild (0-3), moderate (4-5) and severe sedation (6-9).

We asked to each patients about physical triggers and with physical provocation test, we evaluated in all patients if wheals are evoked by a cholinergic or physical stimulus such as water, pressure, friction or cold contact.