I’ve added the image for you. After uploading it, you need to then go to the attachment and insert it into your actual post. It’s not an intuitive step, sorry!
Constant moisture can definitely be a cause of fur loss.
This looks very much like what I go through with Wick on a regular basis. He loses fur on both sides of his mouth.
What’s important to think about is whether this moisture will lead to a fungal infection, like ringworm, which will be apparent with some crustiness and the patch growing larger and larger.
I would recommend silver sulfadiazine (the vet may recommend this as well). If it is fungal, that will treat it. If it’s not, it will still be a nice moisturizer so the skin doesn’t become irritated and bleed from being exposed to elements.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.