Hair loss?

My 7 month old Boston Terrier/Beagle mix puppy seems to be developing ';wear spots'; in the crook of her front legs and body (armpits if she was standing upright.) Is this a common occurrence in some types of dogs?Hair loss?
I agree with Shanna, it isn't a problem unless the skin looks red, irritated, or flakey. If it looks irritated, or if she is very itchy in these spots, you should consult your veterinarian. If it is nice and quiet, and just a little bare, that is normal. My dog's hair is thin under her armpits and on her belly. Like Bostons, my Pit Bull has very short thin hair, and when it starts to 'wear', it is just easier to notice.Hair loss?
yup it's common. don't be surprise that it start to loss it's teeth
He should not be loosing hair in spots he normally has hair. It could be allergies or his diet. If it persists, ask your vet.
As long as it doesn't look red, flaky or irritated, then I wouldn't worry about it. Most dogs do tend to get a litlle bit of that wear look in areas that rub a lot.
They are called hot spots you can get a cream from the vet