Why is my cat scratching his ear raw and bloody with hair loss?

Hi, I am sorry to hear about Sparrow's ear. The inside of his ear looks clean as you have shown in the picture. The back/base of his ear unfortunately looks quite infected. It is great that you are keeping the Ecollar on to prevent him from scratching the ear. Sometimes topical treatment alone will not be able to heal this type of infection. The area looks very moist, either from infection or the ointment(s) that are being applied. Typically when cats have an infected area on their skin, we want the area dry and do not put on topical treatments. This wound would most likely heal very quickly with a visit to Sparrow's veterinarian. The doctor can clip and clean the wound with medical grade gentle cleansing solution and get Sparrow on antibiotics. The antibiotics (which needs a doctor prescription) is the main treatment to get this to heal. I cannot recommend any further over the counter treatments that would allow this to heal. I am sorry about that. I would recommend to keep him indoors only, keep the ecollar on, and hold off on the ointment so the area can dry up. The veterinary appointment can hopefully happen soon and Sparrow will be on his way to healing quickly. Best of luck.

Thanks for using Petco Pet Education Center, formerly Petcoach! This is likely due to allergies. Benadryl is good as is prednisolone for example. However, these are only going to help with the itch temporarily. However, it is crucial to get rid of the allergic component and treat the allergy as if not, the itch will continue. Also, it is crucial to treat the likely secondary infection. There is no at home treatments as the other medication that can be used in cats for this is a prescription medication called prednisolone. One thing you can do at home besides dealing with the possible allergies is using an e-collar which you can get from your local pet store or online to prevent any further self-trauma. It really comes down to figuring out what is causing his allergies so that they can be treated or the specific allergen avoided. There are many things that can cause allergies though in most cases they can be broken down into 3 big categories: flea, food and environmental allergies. Allergies are usually worked up in a stepwise fashion starting with flea allergies as this is the easiest and cheapest to take care of. If not on a flea preventative, then it would be a good idea to get started on one. If already on one then it would be a good idea to change to something else (there are many new products out in the market). If not improved in 1-3 months then it is time to move on and check for food allergies by switching to a novel diet (new protein and new carbohydrate). If that does not seem to be the issue then you are left out having to check for environmental allergies which require blood and/or skin tests. Allergies can be very frustrating to deal with at first but so rewarding at the end when we are able to treat them effectively!

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

 First of all, in order to rule out skin parasites, high quality flea treatment is given. It sounded like your veterinarian has done it already. The next step is to treat the allergy symptomatically and try discovering the cause of the allergy.

 Food can be indeed one the most common cause of it. Some medications can be given by the vet in order to stop the chewing and repair the skin lesions (steroids and antibiotics usually). 

There is also a nice topical spray available, it's called Cortavance and you can get it at the vets.

 Hopefully you will see some results after all this, if not you and your vet should consider starting on a long term allergy treatment.

Unfortunately some tests usually need to be run in order to attempt and find the cause of the scratching, the ears need to be inspected properly to rule out an ear infection, fleas also often cause this type of problem, and it could also be an allergy or some other skin parasites.

First of all it's not a life threatening condition, it's likely an ear infection, very easy to treat, take her to your vet, they will prescribe an antibiotic ear drops and it will solve the problem in no time.

It is definitely an injury but whether or not he did it to himself or it was due to another animal I cannot tell. I do not think there are any bugs there. He may be scratching the ear due to an inner ear infection. I suggest you take DJ to your vet for an exam because is there is an ear infection or something down inside the ear canal you cannot fix/treat that at home. In the meantime you can apply a thin layer of antibiotic cream to the ear twice a day and I suggest you put a "cone" collar on him so he stops scratching the ear and making it worse. https://www.amazon.co.uk/Recovery-Collar-PETBABA-Padded-Elizabethan/dp/B00U7DTNB2/ref=sr_1_3?s=pet-supplies&ie=UTF8&qid=1517593656&sr=1-3&keywords=cat+elizabethan+collar Hope this helps. Best wishes.

This presentation could be due to a trauma (autotraumatism) or localized spot of skin infection (likely to be caused by bacteria). A check up, appropriate disinfection and possibly antibiotics (oral, topical or in a shampoo formulation) are needed to solve the problem. Disinfection may be started at home with very diluted hibiscrub or betadine or salted water baths. Buster collar may be useful as well to avoid any scratching. 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.