What's causing the new sore on my standard poodle's tail and butt?

Thanks for using Petco Pet Education Center, formerly Petcoach! That color indicates saliva staining so she has been chewing at it. This is possibly due to allergies. It really comes down to figuring out what is causing her allergies so that they can be treated or the specific allergen avoided. A secondary infection is likely and also needs to be addressed. Other possibilities such as mange need to also be considered and a physical examination and basic diagnostics should help sort that out. 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!

It sounds like he has a skin infection that needs to be treated again. Maybe he needed to stay on the antibiotics longer, either topical or oral. The bump could be related to the infection, a cyst, or a mass. It may respond to an antibiotic or your vet may need to biopsy or remove it to determine the exact cause. Please call your vet and schedule a recheck appointment. Hope he gets better soon!

Unfortunately, you can’t tell the cause of the rash just by looks alone. It’s possible this is related to fleas in the environment or that this is an allergic reaction. This could also be related to hypothyroidism. I recommend to discuss treating him with a good flea product like Simparica with his veterinarian. If you must use an over-the-counter product, use Frontline. This is still a good product but there are some resistance with fleas. Make sure to protect the area from any licking or scratching with an Elizabethan collar. You can wash the area once a day and rinse it well. Start him on an omega-3 fatty acid supplement. If this does not start to look better within a week or if it starts to get worse, have him examined by the veterinarian. I hope this helps and please feel free to post any additional questions.

I would recommend that you have your dog evaluated by a veterinarian. Possible causes of wounds in the area that you mentioned can be caused by anal gland infection or abscess, perianal fistula, or wounds caused by excessive scooting - which can be caused by intestinal parasites or allergies (fleas, food, environmental, etc). Until you can have your dog evaluated by a vet, it may need to wear an e-collar or cone to prevent licking these areas. Licking will spread bacteria and delay healing.

You had asked what might cause this -- possibilities include an [anal gland abscess](https://www.petcoach.co/article/anal-glands-sacs-impactions-infections-abscesses-in-dogs), [other infection](https://www.petcoach.co/dog/condition/skin-ulcers-and-draining-lesions/) or possibly a tumor. Unfortunately, without a physical exam, a diagnosis cannot be made. Your veterinarian should be able to diagnose the cause after the exam tomorrow. Until then, place an [e-collar](https://www.petco.com/shop/en/petcostore/product/well-and-good-e-collar) (cone) on your dog to prevent licking or chewing. Any treatment will depend on the diagnosis. It is likely the e-collar will need to be kept on until healing is complete.

Thanks for using Petco Pet Education Center, formerly Petcoach! This is possibly due to allergies. 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!

That looks infected. Pets can get infections like bacteria or yeast. Sometimes the infection is related to flea bites or allergies. You must protect the area from licking/chewing by having Denzel wear an elizabethan collar at all times. I recommend to have him examined by the veterinarian and he will likely get antibiotics, an anti-inflammatory (which will decrease the itching and make him feel better) and a medicated shampoo. If fleas are the cause, discuss which flea prevention is best for him. I hope this helps.