Blepharitis, or inflammation of the eyelids, primarily occurs when the eyelids are injured during cat fights. Scratches and surface injuries can easily become infected. This leads to itching and scratching, crust formation, and the accumulation of pus and debris on the eyelids.
Blepharitis can also be caused by head mange mites (Notoedres cati), demodectic mange mites, or ringworm infection. Head mange causes intense itching. Because of persistent scratching, there is hair loss, redness, and scab formation. Ringworm affects the hair on the eyelid, causing it to become brittle and break off next to the skin. This is not an itchy condition. The skin may look scaly and crusted but is seldom red or irritated.
Shedding is a cat’s natural process of losing dead hair. Outdoor cats may lose more hair in the spring and fall and retain more fur in the winter, while indoor cats can shed all year round. Regularly grooming your cat and vacuuming hair from your house should minimize the inconvenience of shedding. However, if you see bald patches in your cat’s fur or notice a significant loss of hair, the underlying cause may be a health-related problem and should be investigated by a veterinarian.
Treatment: Protect the eye by instilling mineral oil, and then loosen the scabs by soaking them with warm compresses. Keep the eye clean and seek veterinary attention. Antibiotics, topical or oral or both, may be required for infected eyelids.
Spasm of the muscles around the eye is induced by pain. This can have numerous causes, including irritation from a foreign body. The irritation causes tightening of the eyelid muscles, which partially closes the eye and rolls the eyelids inward against the cornea. Once rolled in, the rough margins of the lids rub against the eyeball, causing further pain and spasm.
Treatment: Anesthetic drops can be applied to the eyeball to relieve the pain and break the cycle. The relief is temporary if the underlying irritant is not found and removed.
Chemosis (Sudden Swelling)
In cats with this condition, the conjunctiva and eyelids are fluid-filled, puffy, and soft. Water has passed out of the circulation into the tissues in response to the allergen.
Sudden swelling of the eyelids and conjunctiva is generally caused by an allergic reaction. Insect bites and allergens in foods and drugs are the most common causes.
Chlamydophila and viral infections may also cause swelling, but it is primarily of just the conjunctiva.
Treatment: This is not a serious problem. It is of short duration and improves when the allergen is removed. Simple cases may be treated with drops or eye ointments prescribed by your veterinarian that contain a corticosteroid. Some cats may need systemic treatment for the allergic reaction, such as a corticosteroid or an antihistamine.