My dog's armpit skin is purple/black, has ear scabs. What's wrong?

If your pup has been scratching or chewing at the spot, it could be getting red/purplish from irritation. Bruising may also cause a purplish color to appear. Since the site is changing in appearance, it is best to have it rechecked with your vet to make sure there aren't new problems, such as an infection or growth, causing the change. You may also want to use an Elizabethan (cone) collar or T-shirt on your pup to stop her from licking and chewing at it until you can get to the vet. If your pup seems very distressed, or the color is rapidly growing and changing, seeking vet care ASAP is best.

Based on the photos, I am concerned that the purple area is some bleeding/bruising in the skin which we often see when a dog has low platelets. I'm not sure based on the photo, but I suspect the white area is a nipple that just looks really prominent due to the bruising around it. Low platelets are a very serious problem; even though he's otherwise acting fine, please take him to your vet to have him examined. They may recommend running some lab work to find our what his platelet count is. There are many causes of low platelets, some possible causes include an infectious tick-borne disease, an auto-immune disease where his body is destroying his platelets, or cancer. Because all of these are very serious, and because low platelets can lead to life threatening anemia, please take him to your vet. Thanks for asking Petco Pet Education Center, formerly Petcoach!

It is hard to say from a photo but it looks like necrotic skin - maybe from a spider (or other insect) bite/sting. I would suggest a vet visit - not an emergency. That black skin is necrotic (basically dying skin) and usually antibiotics are needed to keep it from getting infected. Hope this helps.

Is there a wound or something stuck in the hair and under the skin? I would try to give him a bath to see if you can scrub some of the black stuff off to get a better look at the skin. If there is a wound there then it will need to see a vet to have the hair clipped and treated appropriately.

I don’t see a distinct bump in your picture although I do see some purple at the outer edge of the ear. I’m wondering if Kujoe might have an aural hematoma, or a blood clot in the ear. I’d recommend having your vet examine him in person to determine what this might be.

This could be skin irritation/infection but it could also be subcutaneous bleeding (which can be serious). I strongly suggest you have him examined by a vet. In the meantime you can try these medicated pads on the affected areas in case of infection. ( https://www.chewy.com/douxo-chlorhexidine-3-ps-pads-dogs/dp/110823 )

Poor Shay-Shay! It looks like she has some pretty significant skin problems. The black, crusty appearance of the skin on her belly is called lichenification - it's caused by chronic itching over a long period of time. There are a number of things that could cause severe itching, hair loss, and scabs like this. Some common possibilities would include allergies, fleas, a bacterial or fungal skin infection, or skin mites (mange). Treatment will depend on what the underlying problem is, so it's important to get a diagnosis first in order to know how to help her. I would recommend taking her to the vet this week for an exam - he/she can do some simple skin tests to help diagnose the problem and get her started on appropriate medication to treat it.