My Dog has a rash, and constant sneezing

Question
I have a female minature pincher that has, for the past 3 years, has gotten a rash on her belly area that seems to come around during the summer months.  She scratches at the area as well as use her mouth to scratch the area.  I took her to the a vet before and he said there is nothing wrong but I believe there is.  Also in the past week she has begun sneezing a lot as well as making a noise like she has a stuffed nose.  Could she be allergic to something that causes this rash as well as these sneezing and snorting symptoms?  

Answer
She most likely has atopy (inhaled allergies).  The best thing to do is to wipe her feet and belly off with mixture of vinegar and water when she comes inside to remove some of the allergans.  If the rash looks like pimples or is crusty, than that is a secondary infection and should be treated with antibiotics.  You can try giving Benadryl to see if that helps reduce the itching...1 mg PER pound of weight, 2-3 times a day.  Also, mix some fish or flax seed oil (1/4 adult dose) as well as Ester C (5-10 mg per pound) into her food twice daily to help combat allergies.