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Case Report


Urticaria Due to Antihistamines


L Sánchez Morillas,1 P Rojas Pérez-Ezquerra,1 M Reaño Martos,1 ML Sanz,2 JJ Laguna Martínez1

1Allergology Department, Hospital Central de la Cruz Roja, Madrid, Spain
2Allergology Department, Clínica Universidad de Navarra, Pamplona, Spain

J Investig Allergol Clin Immunol 2011; Vol. 21(1): 66-68



H1-antihistamines are probably the most frequently used drugs in allergic diseases, with widely established efficacy, tolerance, and safety.
We report a patient with urticaria due to ingestion of ebastine and fexofenadine. Skin prick tests, patch tests, and basophil activation tests with the implicated drugs and antihistamines from other families were negative. The oral challenges with the implicated antihistamines and other antihistamines tested were positive, but the patient tolerated an oral challenge with cetirizine. We present a patient with urticaria
induced by different antihistamines in whom the diagnosis was established by oral challenge. The mechanism of sensitization remains unclear.

Key words: Adverse drug reaction. Antihistamines. Cross-reactivity. Urticaria.