Why is my cat biting his paw and losing fur? Vet found no cause.

This is probably due to a severe allergy, although it could also be fleas, infection or mites.

First of all, in order to rule out skin parasites, you will need to treat with a high quality flea treatment (advocate or advantage), then ask the vet to perform a skin scrape - this might reveal an infection or a mite infestation.

 If all of those came back negative, the next step is to treat the allergy symptomatically and try to discover the cause of the allergy.

 Three main type of allergies are usually affecting pets: food allergies, flea and parasite related ones and environmental type (allergens coming from trees, pollins, dust etc etc). Some medications can be given by the vet in order to repair the skin lesions (steroids and antibiotics). Please do not hesitate to contact us again on the forum or by requesting a consultation (where you can post pictures ) if you have any more questions or to discuss it any further.

Hi there and thank you for using Petco Pet Education Center, formerly Petcoach to address your concern. I would suspect that this could be from another cat, some other animal or a puncture wound from a sharp object. It sounds as though the lesion is infected with your description. I would recommend soaking the foot in a mixture of betadine and water until you have a light brown solution. Soak the foot with this solution twice daily for 10 minutes at a time. If the foot does not improve, I would recommend having a veterinarian take a look at this so that the most appropriate diagnostic and treatment recommendations can be made. I hope this helps! Please let me know if you have any other questions or concerns and I would be more than happy to help you further.

I would be very suspicious about possible allergies with these symptoms. I recommend rechecking with your vet, as that skin on the legs looks pretty raw and you need to make sure Cindy doesn't have a secondary infection. Then you can talk to your vet about whether they think it's appropriate to start Cindy on an allergy medication / food trial. Anxiety / behavioral overgrooming and parasites (fleas, mites) are other common causes of hair loss, and with an exam your vet can help differentiate these.

Such overgrooming in cats can be related to allergies or anxiety - feeding a calming food such as royal canin calm or adding a claming supplement containing b vitamins, tryptophan and casein can also help. Occasionally antiinflammatory medications may need to be prescribed by your vet in order to break the recurrent itch-scratch/groom cycle and allow the skin to heal

It may be a contact allergy to something in the environment. I suggest you put an E-collar on him to stop the licking and apply this spray to the affected area. If after a week it is not better then take him to your vet for an exam. ( https://www.amazon.com/Pet-Cute-Comfy-Cone-Water-Resistant/dp/B01M9I7NGK/ref=sr_1_2?keywords=cat+soft+e+collar&qid=1580747169&sr=8-2 ) ( https://www.amazon.com/Vetericyn-Plus-Feline-Wound-Skin/dp/B01M28PQLR/ref=sr_1_8?keywords=vetericyn+cat&qid=1580747200&sr=8-8 )

This lump/bump/growth should be ideally examined by your local vet to have a diagnosis established. Your vet may want to perform an FNA (fine needle aspiration) or a biopsy to sample the bump and determine its underlying nature. Differentials would include infections, a skin cyst, benign or more malignant type of tumors. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!

Persistent and recurring itchiness without obvious physical cause such as fleas is a red flag for allergic skin disease. It would be impossible to assess the case fully without a complete review of all previous tests and response (full, partial or none) to previous treatments and diet changes. My general approach would be a full physical exam and skin scrapes to rule out infections, ringworm and parasites such as fleas or mites and treatment of any of these as required. Following this, a diet trial of a hydrolyzed food such as royal canin hypoallergenic for 8 weeks to rule out adverse food reactions or sensitivites. If no response to food trial, skin biopsies and allergy medications would be considered, as well as blood tests for allergies and underlying medical causes. Referral to a specialist, certified dermatologist is always worthwhile in complex skin cases