What are the possible causes of a rash on a dog?

Rash most popular product development: issue of KS : What are the possible causes of a rash on a dog Last night my dog ​​was left with a pretty nasty rash on her inner thighs and on his "armpits". It's like it has some scratches as well. I am home with my family to stay and watch their dogs. I thought it might be poison ivy, but all the dogs running in the same area, and the other two have no symptoms. I have not fed anything else. The leg that looks like the worst (not crude) also has

Itching Urticarial Rash