What should a client taking fexofenadine (Allegra) do prior to allergy skin testing?

A client taking fexofenadine (Allegra) should reschedule the appointment for allergy skin testing because fexofenadine is an antihistamine. Antihistamines can interfere with the results of allergy tests by blocking the action of histamine, which is a key mediator in allergic reactions. When a patient is on antihistamines, it may result in false-negative test results, making it difficult to accurately determine the client's allergies.

For accurate allergy skin testing, it is typically recommended that patients avoid antihistamines for a certain period before the test, allowing their body to react normally to allergens. Therefore, rescheduling the appointment ensures that the client is not under the influence of the medication, leading to reliable testing outcomes.