Cats are like our selves they can develop allergies. This happens when their immune systems become sensitive to their surroundings and substances.
The main issue is usually flea allergies. I have a couple of cats that are very sensitive to fleas. Some flea solutions just do not seem to work or stop working.
Their skin can become itchy and can be associated with allergic dermatitis. They may also show symptoms like sneezing, coughing, and wheezing, itchy runny eyes, vomiting or even diarrhoea, snoring caused by inflamed throat and in some cases, paw chewing or swollen sensitive paws.
However, shedding fur is a natural part of feline evolution. It is important to recognise when the situation is not natural. Which is thinning fur or even baldness in some spots most situations are easily treatable.
Areas you may notice most thinning underside of the tail, tail itself, hind legs, sides, or genital area the skin could be itchy, scaly, or dry skin, red patches on the skin dandruff or excessive shedding.