Related Experiment Video
Updated: Jun 4, 2026

Basophil Activation Test for Allergy Diagnosis
Published on: May 31, 2021
Urticaria due to antihistamines
L Sánchez Morillas1, P Rojas Pérez-Ezquerra, M Reaño Martos
1Allergology Department, Hospital Central de la Cruz Roja, Madrid, Spain. lsanchezmorillas@hotmail.com
Abstract:
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.
Related Concept Videos
Allergic Reactions: Anaphylaxis
Allergic Reactions
Drug Toxicity: Allergic Reactions
Allergic Drug Reactions
Hypersensitivity Reactions: Immune-Complex Reactions
Upper Respiratory Drugs: First and Second-Generation Antihistamines
Histamine binds to specific receptor sites, known as H1 receptors, on tissue cells, triggering inflammation and swelling. Antihistamines combat these effects by competing with histamine for these receptor sites. By...
