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For most cats, one or two fleas aren't a serious problem. However, in the rare case that your cat has a flea allergy, even a few small bites can lead to dry, irritated, and flaky skin. A vet can help you determine whether or not your cat has an allergy. If your cat has an allergy, the vet can also recommend treatment options. Common remedies for fleas include licensed pesticide shampoos and ointments proven to be effective. If your cat is at risk for an infection, the vet may also recommend antibiotics. Luckily, most cats recover quickly with flea control treatments. Just like people, cats sometimes have allergies to the things that they eat. If you can't find an obvious cause for your cat's dandruff, this may be the explanation. Your vet can help confirm your suspicions.  If your cat does have an allergy, you may need to switch to a different food at your vet's recommendation. If this keeps the cat from getting nutrients it needs, dietary supplements may be necessary. In some cases, switching dry food for wet food and adding a little fish oil to each meal can help keep a cat's skin moisturized. It may not seem like a risk that's worth worrying about, but cats can have their skin damaged by the weather. This is especially true for cats with thin coats (or none at all). Hot, dry conditions can lead to dried-out skin and even sunburn, so let your cat stay indoors when it's scorching out. Drier winter months can also be a source of flaky skin if your cat lies next to a heater or fire, even if there's less of a risk of sunburn. Cats aren't like people in terms of bathing needs. They're quite good at keeping themselves clean, so they only need to be bathed very infrequently. Unless your cat's coat is visibly dirty, oily, or matted, you won't usually need to bathe it more than a few times per year. Bathing the cat more often can strip the essential oils from its skin, leaving it dried-out and flaky. See our article on bathing a cat for help if you do need to wash your cat. The causes for dry skin above are just a few of the most common possibilities. A wide variety of medical conditions (some serious, some not) can also cause dry skin. Only a vet can rule out these causes, so don't hesitate to get professional help. Just a few other causes for dry skin include:  Diabetes Seborrhea Hyperthyroidism Ringworm Malassezia
If the cat is allergic to fleas, treat them. Change your cat's diet if it is allergic to its food. Keep your cat out of hot, dry weather. Avoid bathing your cat too often. Take your cat to a vet for a medical diagnosis.