Hi, Michael,
 
*If* it is a sinus infection, antibiotics should clear it, just as they
do in people.  Make sure that your vet is sure that it is an infection,
though.  My big red eyed white Pertwee has seasonal allergies, just as I
do.  If the leaves are changing in your area, this is allergy season.
Pertwee's allergies seem to parallel mine pretty closely, and all our vet
has us do is give him .4 cc of Benadryl elixir, which relieves the sneezing
and running and helps him.  We usually do that after play time so he can
get some rest.
 
BTW, please do not quote me on the dosage, but rather have your vet decide.
Pertwee is a big boy, and I suspect the dosage is related to body weight.
 
Good luck!
Caity
[Posted in FML issue 2847]