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.

• Antihistamines
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.