Management of Chronic Spontaneous Urticaria Exacerbated by Antihistamines: When Treatment Can Act as a Causal Agent Itself.

Abstract

AlthoughH1- antihistaminescurrentlyconstitutethelargestclassofmedicationsusedinthetreatmentofallergicdisorders,somecasesofhypersensitivityreactionsduetovariousantihistaminepreparations,suchasfixeddrugeruptions,contactdermatitis,maculo- papularrash,andurticarialreactions,havebeenreported(1).Wereporthereintwopatientswithchronicspontaneousurticaria(CSU)inwhichantihistaminesactedasexacerbatingfactorsofthediseaseandrequiredanalternativetreatment.Theunderlyingmechanismintheseparticularcasesisnotentirelyclear,butatype-I(immediate)hypersensitivityreactionshouldbeconsidered