Have Cat Questions? Ask a Cat Vet Online.
Hello, this is Dr. Jess. I am sorry to hear about your kitty! How long has she had the scabs and hair loss? Did she have fleas a few months ago?
Ok. And is she an indoor only kitty?
The most likely culprit would be an allergy related to flea bites. This could be why one of the kitties has the problem but not the other. Even if both kitties were exposed to fleas, if one of them has an allergy to flea bites and the other does not, the reaction to the presence of fleas can look different in the two cats. A cat with a flea allergy might develop a big inflammatory response to just a few fleas biting her and the reaction could cause a cascade of events (her itching and biting the skin, which can cause trauma and inflammation, leading to more itching and also a pathway for bacteria to enter the skin and cause a secondary infection. A cat without an allergy to fleas might get a few bites, itch for a few days and be done with it. This would be the most likely reason for the cats to look so different in terms of their skin.
I am glad to hear you have been treating them for the past three months. What product are you using? I am going to attach a few articles here FYI on flea control in allergy cases as well as itch relief in pets:
The safest and quickest way to see results would be to bring your kitty in for your vet to examine. Oftentimes these guys require a short course of steroids to get the inflammation under control and some also need a course of antibiotics because of secondary skin infection. If you cannot get your kitty in to see the vet soon, you could consider starting a fatty acid supplement (you can find these at your local pet store as a liquid to squirt on the food or a gel cap) which can help decrease inflammation, and an antihistamine such as chlorpheniramine. Here is an article on that medication: http://www.petplace.com/article/drug-library/library/over-the-counter/chlorpheniramine-maleate-chlor-trimeton. With any medication, even over the counter, it is recommended that you call your vet before starting the medication to determine if they feel it is appropriate for your individual pet, as they know your pet's medical history and medications best.
Please let me know if you have any additional questions. If you do not, please take a moment to click and rate our conversation so we can know if you were satisfied with your service and I can get credit for helping to answer your question. Thank you and best of luck!!!