Why is my cat always hungry, losing weight, and losing hair?

Hi and thanks for posting on Petco Pet Education Center, formerly Petcoach! Hair loss can have many causes in cats- skin infection such as a bacterial infection, allergy such as to food or a flea allergy (especially if Simba is not on any flea preventative) or fungal infection like ringworm can all be causes. Sometimes anxiety can cause cats to lick off their fur but this is typically a diagnosis that is made after all other health conditions are ruled out first. The weight loss could be due to due to simply eating less (this would be a good thing if Simba was previously overweight). Of course, weight loss can also be caused by many different underlying health condition such as certain infections, hyperthyroidism, liver, kidney disease, certain cancers and other endocrine disease. I would recommend Simba see his veterinarian soon for an evaluation. Your veterinary may take a skin scraping and hair sample from the area of hair loss and may recommend running blood work or other diagnostics as necessary. I hope this helps!

Cats who are thin despite eating well who also have areas of baldness can be suffering from an endocrine disease called hyperthyroidism. I recommend getting his thyroid levels tested by a veterinarian who does this type of testing.

Poor Little Sarge. It could be she has a medical condition like hyperthyroidism causing the hair loss as well as the increase in drinking and weight loss, or she could be suffering from something like a skin infection causing the hair loss, and a medical condition like diabetes causing the weight loss and increased thirst. I would take her into the vet for blood work or a urinalysis. The vet can diagnose what is causing her symptoms, and can teat her. I hope this helps!

Significant weight loss is always a concern, especially if his appetite is good. Hormonal conditions such as diabetes and thyroid disease or poor absorption and digestion of his food is possible and I would recommend a full physical and blood panel as soon as possible in order to stabilise his condition before he becomes too frail

These are indeed an unusual set of symptoms, thyroid disease and diabetes would be the first suspects for a cat with increasing appetite and weight loss. A specialist ultrasound scan of the abdomen may be worth while to investigate difficulties with food digestion and absorption or even tumours using up the calories

This is concerning, and weight loss despite eating can be a sign of a medical condition like diabetes. The hair loss could be due to fleas, mites, or allergies. You need to have Bean seen by a vet for these issues, and I recommend getting blood work and a urinalysis done. I'd take him into a vet today.

Older cats like your kitty often get an overactive thyroid which will show weight loss, a really fast heart rate, sometimes vomiting, and more vocalisation than usual. Some cats get skittish as well. Hyperthyroidism can actually cause heart problems and mask kidney disease. Hyperthyroidism is easily diagnosed with a clinical exam and a little blood test and there are various treatments available, varying from Methimazole transdermal ointment or tablets to slow down thyroid hormone production, surgery to remove the overactive thyroid gland or radiotherapy. If your kitty is suffering from hyperthyroidism your vet will discuss the various options. I suggest you make an appointment tomorrow.