Thank you for your question. I'm sorry to hear about your Blyken's sores.
Unfortunately, there is a very long list of possibilities for what can be occuring above your cat's eyes. To make it more difficult, there are about 20 different more-common causes that can look identical! Even if you were to post a picture or I examined the lesions, I would need to do more tests to determine what the lesions were, and what caused them.
Typical tests I perform on a first visit with lesions of this description are:
wood's lamp exam
On a second or third visit, possibly cultures and a punch biopsy if necessary (if the other tests are inconclusive, or if the lesions continue to return despite treatment).
More common causes would include self-trauma (scratching or rubbing from itchiness), trauma from the other cats, ringworm
, demodex, allergies, such as food
, flea, inhaled, or contact irritants, mast cell tumors, herpes, various bacterial or fungal infections, autoimmune complexes, squamous cell carcinoma or other cancers such as mast cell tumor (hopefully not this!!) or eosinophilic granuloma complex.
Since the lesions appeared to resolve or improve greatly with the steroid injection, there may be an allergy component or it could be due to eosinophilic granuloma complex. However, I would have expected improvement for several weeks - or longer - depending on which steroid was administered.
At this point, I would revisit your vet and request at least a skin scrape, dermatophyte test, and skin cytology, and consider antibiotic treatment if indicated along with addressing potential allergens - as a good starting point.
I like that you are thinking scientifically and changing the litter back. You may wish to investigate other potential allergens/irritants in your house, and even though your cats are indoors and you probably see no evidence of fleas, I would recommend strict monthly flea control for any cat that showed potential signs of allergies. Again, you would never see evidence if there is only a bite or two a month, but it could trigger a severe allergy in a sensitive patient.
You can search eosinophilic granuloma complex, allergies, itchiness in cats, and other topics at veterinarypartners.com.
Please let me know how else I can help. I hope this information helps you and Blyken!