[header] How to diagnose feline upper respiratory illness [title] Keep an eye out for nasal discharge. [step] Like a cold or flu in humans, a urti will be uncomfortable for a cat because of the symptoms associated with it. A cat suffering from a urti will usually exhibit nasal discharge and the irritation associated with that. 
[substeps] Nasal discharge can cause the cat to have a very crusty nose. When the discharge is not wiped away, it can dry under and around the nose area.