Rash on my 10 month old lab

Question
My female 10 month old Chocolate Lab has a rash in her armpits. She had been wearing her harness that goes around her armpits, for the past 4 days and I just noticed the redness and tenderness so i took it off of her. Is there anything i can do to help the healing process? She has been itching herself an awful lot lately and was wondering if she could have an allergy also?

Answer
Is the harness leather? If not don't use it again. She could be allergic. I hate harnesses anyway for many reasons. It could also be causing irritation under her front legs. Check her for bugs as well(fleas etc). If you give her a bath in dawn dish washing liquid, leaving it on for five minutes before rinsing and rinse WELL, if there are any little friends on her that should take care of it. Then wash her again in Aveeno shampoo, or use aveeno in a bath to soothe her itchiness. Check her dog food for by products,wheat, soy and other fillers. These are primary villains when it comes to allergies in dogs and should never be fed to any dog.
Let me know how she does
Diane