liquid benadryl on cats food?

I've been told to start giving my cat a minor dose of childrens benadryl for his allergies but i'm having such a hard time giving it to him!
He hisses and scratches and starts foaming at the mouth and is such a fussy thing to give medicine too.
since it's such a small amount anyway, would it be alright to just mix it up in his wet food to give it to him? 
i know you can do that with a pill, but is the same thing ok for a liquid?
thanks!

No I dont think he would eat the food because of the smell difference. The reason he has the foaming is because it has a bitter taste. Its just a natural response. 

You mentioned you've been told, so just wanted to make sure it was your veterinarian who instructed you to do that?

You can try mixing it up with food, but the general advice by site members is usually to ask the vet to prescribe tablets instead. They can then be administered in pill pockets and are generally less disgusting for cats.

You may want to read this thread -

 [thread="296721"]Childrens Benadryl How To Administer​[/thread]  

l-lysine caplets (powder inside them) might help a bit with allergies. Obv. it helps a lot with other various sinus/eye issues too. TRY IT. Its cheap and very effective for most cats with herpes etc...