Why is my cat losing hair under his armpit and overgrooming?

Hi there, Thanks for the good picture. This is quite an inflamed patch of skin that Hamilton has. The pink granulation tissue tells me it's been present for likely a week already. Its difficult to tell without physically feeling around and palpating the wound, associated lymph nodes, and other physical exam findings. It could be an old wound that is in the healing stages or it could be something like a skin plaque that is growing and worsening. It looks like he has been spending a lot of time licking at it, indicating itch or pain. I recommend taking Hamilton to see his veterinarian for a full physical and they will be able to advise best for diagnostics and treatment after seeing him. I hope this helps. Thanks for using Petco Pet Education Center, formerly Petcoach.

It looks as though your cat is over grooming which is causing the hair loss. The most common cause of over grooming in cats is allergies. The allergies cause skin infection and excessive itchiness. The discoloration of the skin is because of this as well. I would recommend taking your cat to the vet so the skin infection can be treated and they can give Buddy something to help with the itch.

Hi, and thanks for your question. This could be due to an allergy, although it could also be infection or mites. First of all, in order to rule out skin parasites, you will need to treat with a high quality flea treatment, 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, pollens, dust etc etc). Some medications can be given by the vet in order to repair any possible skin lesions (like steroids and antibiotics). The following products can be found online and can be tried as a first line approach: Douxo PS Calm shampoo, Essential 6 spot on by dermoscent, Krillex Krill oil chews. 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!

[Allergies](https://www.petcoach.co/cat/condition/feline-allergies/) are the most common cause of hair loss and [excessive grooming in cats](https://www.petcoach.co/article/excessive-grooming-in-cats-what-it-means-and-how-to-help), but there are several other medical causes as well - including [fleas](https://www.petcoach.co/article/5-tips-to-get-rid-of-fleas/), bacterial or fungal infections, or skin mites. I would definitely start your cat on a good monthly spot-on product such as [Advantage II](https://www.petco.com/shop/en/petcostore/product/cat/cat-flea-and-tick/cat-flea-and-tick-drops/advantage-ii-once-a-month-cat-and-kitten-topical-flea-treatment-over-9-lbs) to make sure fleas are not the problem - you can get this over the counter at many pet stores. If this doesn't resolve the problem, you will need to have your cat examined by a vet - he/she can do some testing if needed to diagnose the problem and get your kitty the appropriate prescription medications to treat it. Behavioral causes, such as stress or anxiety, can also lead to overgrooming. [Calming supplements](https://www.petco.com/shop/en/petcostore/category/cat/cat-training/cat-training-calming-aids/calming-cat-supplements) or [pheromone products](https://www.petco.com/shop/en/petcostore/brand/feliway) can be found at the lcocal Petco. If these do not improve the condition, your veterinarian may recommend prescription strength remedies.

If he seems to be losing weight, I would make sure her thyroid level was tested. If so, the skin could be due to an allergy or other skin condition. Thyroid level being high can cause skin and hair changes so I would first get this level checked out. As for the skin, you can use Douxo PS calm shampoo and mousse, both of which can be found online quite easily. I hope this helps guide you in the right direction! Please let me know if you have any other questions or concerns and I would be more than happy to help you further.

It definitely looks like he is suffering from some skin infection. This could be due to an allergy or infection. Your veterinarian will likely need to do some testing to determine the causative agent. I would recommend placing a cone on him to deter licking and have him seen by a veterinarian.

It would be hard to say without an exam. Issues such as parasites, infections, irritation, fungal infections, etc can all cause hair loss. If the shampoo used during a bath caused irritation, this could also be related. If the hair loss is very itchy, spreading, there is lots of redness, visible flecks of "stuff" or it is not improving, having a vet take a look in person is best for determining what is causing it.