Excessive Shedding

[.unknown.]

Is there a disease or syndrome that would cause a dog to grow it's coat like it's winter, but shed like it's summer? My dog Suzie who is a short haired pitbull mix and had a short coat, but it's all fluffy like it's winter, but she is shedding gobs and gobs of hair. She even shed like this in winter. This is not her normal shedding amount...

I took her to the vet and it was recommended that she get a bath with shampoo for dry/allergic/sensitive skin, which I did, to no avail.

She has no bald spots...

She's eating Go! Now! Senior/Weight Management food as she gained a few pounds during winter and we're trying to work off the extra weight, combined with exercise.

She has her annual check up next weekend, but I am wondering if this type of shedding is common with allergies, maybe?

I'm perplexed. I switched her to innova EVO, to see if that could help rule out a food allergy she might have with the Go!, but she got really bad gas and had diarrhea every time she ate it.

I also looked up Hypothydroidism....maybe a blood test is in order...