Horse sheds to skin

Question
I have a 22 YO sorrel QH mare that I recently rescued with a gelding.  We have got them back to health, and now that it is spring, everyone is shedding.  I have noticed that she is shedding out to almost a black, which I now realize is her skin.  I have been around horses my whole life, but am unfamiliar with older horses like her.  I am wondering if it is normal for older horses like her to shed out like that, and if not, then what can I do to help her get her coat back? Thanks for any suggestions...

Answer
Kaci,
 It sounds like she may be having a medical complication which is causing the massive shedding down to the skin.  I would have your vet check her out for things like thyroid problems, cushings disease, etc.  These are very common in older horses, amd can be maintained with medication.  However the shedding is not normal if she is going bald.
Samantha