Carrots are rich in carotenes, which are substances related to vitamin A. They're found in the orange pigments and are good for you, but, if you eat lots and lots of carrots, you can develop a yellowish or orange cast to your skin. It's mostly noticeable on the soles of your feet and the palms of your hands.
Benadryl is another decongestant safe for use in cats, although it is usually not as effective as chlortrimeton in treating congestion. Benadryl is generally more beneficial with treating snake bites, reactions to vaccinations, itching, and insect bites.
Decongestant drops may be recommended to shrink swollen nasal membranes. Topical ointments and artificial tears are available for cats whose eyes are affected. Topical or systemic antiviral drugs may also be appropriate. Appetite stimulants can help cats that are anorexic, and pain medications (analgesics) can help cats with oral sores. The amino acid, L-lysine, can be helpful to reduce the severity of respiratory infections in cats that test positive for feline herpesvirus.