Why is my senior cat losing hair with sores and dark discharge?

She could have a skin infection and/or an allergic dermatitis. She may need an antibiotic and/or corticosteroid to help treat. It would also be a good idea to recheck her thyroid level if she hasn't had it checked in the last 6 months.

There can be many causes of sores in cats, including bacterial infection, ringworm, mites, fleas, allergies, and, yes, cancer is also a possibility. I would recommend that Carmen be examined by a veterinarian. After a thorough physical exam, your vet may recommend diagnostics like skin cytology to look at cells under a microscope, skin scrapes to look for mites, fungal cultures to identify ringworm, or biopsies to look for cancer.

There are a multiple things that can cause hairloss in cats including bacterial infections, fungal infections (ringworm), allergies, mites, and fleas. She should be examined by a vet to determine the cause and treatment. Your vet may need to do some diagnostic tests to diagnose the problem.

While it is hard to say exactly what the cause of Bella's hair loss may be due to without examining Bella first, I can offer some possibilities and next steps. Some possibilities may include a fungal infection, bacterial infection, mites, a food or environmental allergy, or evidence of an underlying endocrine disorder such as a thyroid problem. Your veterinarian can diagnose these potential conditions with a fungal culture, skin scraping, and some blood work. I would recommend Bella visit her vet soon to have the possibilities above ruled out so she can get the most appropriate treatment.

This looks like an infectious case of dermatitis. It could be caused by bacteria, fungus or parasites. It is pretty severe, she needs to see a vet who can test her skin. To treat it she will need to be treated for parasites, antibiotics and a medicated shampoo. If it is fungal or allergy she could need other medicine also.

This is actually very concerning. I suggest you get her to your vet as soon as possible. I would be very worried that this is skin cancer (like squamous cell carcinoma) because of her coloration (white), the location of the lesions and the duration of the lesions. https://vcahospitals.com/know-your-pet/skin-squamous-cell-carcinoma-in-cats

You will need to take your kitty to a veterinarian for a skin exam. Summer could be suffering from an allergy, mites, fleas, a bacterial or fungal infection. Each of these requires a different treatment, so it is important to find out what is causing the itch. Your vet will do a thorough exam and maybe a a skin scrape. He will then discuss the options with you and then prescribe medications, possibly give an injection to stop the itching.