What is solar dermatitis?
Solar dermatitis is a skin disease caused by exposure to the sun. It occurs mainly in cats with white or pale patches of skin that are non-pigmented areas.
"The most commonly affected areas in the cat are the ears, but the nose and the eyelids are sometimes involved."
The most commonly affected areas in the cat are the ears, but the nose and the eyelids are sometimes involved. In the early stages of solar dermatitis, the skin may look pink and scaly with some hair loss. As the condition progresses, the area becomes crusted and ulcerated. The lesions appear to cause irritation, and the cat may shake its head or scratch at the ears, causing bleeding from the ear margins or tips. Sometimes the condition progresses and a malignant tumor called a squamous cell carcinoma develops at the site.
What can be done to prevent the condition from worsening?
"Sunlight should be avoided."
Sunlight should be avoided. This is best achieved by keeping the cat indoors between the hours of 10:00 am and 4:00 pm on sunny days. If this is not possible or if you live in a house with lots of windows and your cat likes to sun itself in the windows, you should apply sun block on the affected and thinly-haired areas. Unfortunately, many cats will rapidly lick the sunscreen off. Since some products may actually be toxic to cats, never use a human sunscreen preparation without first checking with your veterinarian.
How will I know if my cat has squamous cell carcinoma?
Your veterinarian will recommend taking a tissue biopsy from the affected area if there is any concern that the condition may be progressing to squamous cell carcinoma. Most cats will need sedation or general anesthesia before they will allow your veterinarian to perform this procedure. The biopsy will be sent away to a veterinary histopathologist who will examine it under a microscope to see if malignant cells are present.
For more information, see our other, related handouts on squamous cell carcinoma.