Advices from our vets
The bottom of your dog’s limbs may turn brown, either because its coat is very light, because it licks its legs a lot, or because it goes in water! In that case, this may be due to a fungal infection (invisible to the naked eye) that can be itchy. It may also be that your dog is anxious. In any case, talk about it with your veterinarian.
You can use wipes to soothe your dog.