Before directly using the inhalers, please check the mouth and nostrils and even make the patient rinse the mouth because as you mentioned, the allergen or any stimulant mediating the mast cell reaction present in mouth can over trigger the asthma as you use inhaler! So make the patient rinse and use the inhaler if possible . Thanks !
And yes after reading this ,I can say that you had a experience about the asthmatic patient and know the probable cause and treatment modalities ! Happy for you :)