The application of patch testing is not compatible with the taking of various types of drugs:
• High-dose corticosteroids
Former work helped clarify that taking corticosteroids at a dose equal to or greater than 20 mg prednisolone/day results in the possibility of false negatives. Than this dosage is compatible with the testing, but the results are to be interpreted with caution.
• Other immunosuppressants
It is not appropriate to patch testing in patients under azathropine, methotrexate, ciclosporin, mycophenolate mofetil, tacrolimus. Under ciclosporin (at a dose of 3 mg/kg/day), can be mitigated positive patch testing, but it is not impossible to think that there is a number of false negatives.
In contrast, taking antihistamines, including the latest as cetirizine, fexotenadine hydrochloride, the mizolastine and loratadine is no problem for the implementation of patch testing and should not be interrupted.