Abstract

Background: H₁ antihistamines are important drugs for the treatment of urticaria and are commonly well tolerated. Cases of hypersensitivity reactions to antihistamines have rarely been reported, the underlying pathomechanism is unknown yet. Case report: We report the case of a 28-year-old female patient suffering from chronic spontaneous urticaria who experienced severe episodes of wheals and flares induced by different H₁ antihistamines. Methods: We performed skin prick tests (SPT) with a diversity of H₁ antihistamines and CAST and FlowCAST analyses. Moreover a placebo controlled oral challenge test to mizolastin was done. Results: We saw positive SPT reactions to nearly all H₁ antihistamines tested with the exception of mizolastin. We observed neither a release of sulfidoleukotrienes nor an upregulation of basophil activation markers in the CAST and Flow- CAST analyses. The oral challenge test with mizolastin resulted in the development of generalized wheals and flares. Conclusion: H₁ antihistamines are effective drugs for the treatment of urticaria but they may lead to hypersensitivity reactions in rare cases. Because of the negative CAST and FlowCAST results, an IgE-mediated pathomechanism is improbable. We propose that hypersensitivity reactions to H₁ antihistamines may be induced by a paradox H₁ receptor activation.

Author Details

Authors

• J. Durda¹
• B. Wedi²
• V. Martin¹
• K. Breuer¹

Departments

• ¹ Abteilung für Allergologie und Berufsdermatologie, Dermatologikum Hamburg,
• ² Klinik für Dermatologie, Allergologie und Venerologie, Medizinische Hochschule Hannover

Address

PD Dr. med. K. Breuer
Abteilung für Allergologie und Berufsdermatologie
Dermatologikum Hamburg
Stephansplatz 5
20354 Hamburg, Germany
Email: [email protected]

Citation