Expert: Dr. Louis N. Gotthelf - 6/10/2006

Question
My korat or russian blue (not sure) cat, Sasha, has scabs on the outside of her ears, which are almost bald.  It seems to become exacerbated by sunlight, resolving when she's spent several weeks indoors out of the window light.  She's not on advantage right now.  We live in a very hot humid climate.  She's about 11 yrs old.  Any suggestions?  She had these when she was an exclusively indoor cat in an apartment as well.

Answer
Tis is most likely a solar dermatosis.  It is similar to a pre-cancerous lesion in people called actinic keratitis. Some of these  cats will go on and develop squamous cell carcinomas.  

I would recommend keeping the cat indoors as much as possible. Some people use sunscreens on the ears to control this reaction from sunlight.