Carol C. contacted us via our Facebook page. Carol writes:
Carol, the symptoms you list indicate that your cat may have a viral infection, but there could also be a bacterial component. Only your veterinarian can determine this for you. If your cat's situation doesn't improve soon, you should make an appointment.
If your cat's infection is just viral, your cat's immune system will usually sort it out with a little TLC from you. A humidifier will help as will making sure he continues to eat plenty of food and drink plenty of water. If he's on a dry food diet, now's a good time to begin switching him over to wet food exclusively. He'll need the extra fluids. You should also help him keep his nose and eyes clean by wiping them gently if he'll allow it.
If your doctor determines that there is a bacterial infection, he or she will prescribe a course of antibiotics. If that's what's needed, follow your doctor's instructions explicitly. Once you're done, your doctor may require one more visit to insure that the infection is gone. At that point, you'll want to consider a probiotic to replace your cat's good bacteria, as the antibiotics will wipe everything out. See this post on kitty digestion issues for more info on that.
It's also remotely possible that your cat's sinuses are being irritated by something he inhaled. Some allergens and even small seeds can cause cold-like symptoms in cats. We even had a cat who'd tried to catch a bee and the bee had stung her inside her nose with disastrous results. Only your vet can help you know for sure what's going on.
You clearly love your feline friend. We're confident that with the right care, he'll be rid of this malady in no time!