To see if you have cellulitis, your doctor will ask if you have had any recent surgery or dental work. They will also ask if you have had recent face or skin wounds, and chest, lung or sinus infections.
Your doctor will also examine your eyes.
To diagnose the type of infection you have, your doctor will probably do some tests. If they think you might have preseptal cellulitis, they may test tissue from your nose or eye. If they suspect orbital cellulitis, they may do a blood test.
In some cases, your doctor may also have you get a scan of the affected area. These images will help your doctor see where the infection is within the orbit.