This can be a sign of a number of things including, an inability to groom. This can arise due to obesity, arthritis,etc. Certainly a bad coat in this area can arise from issue like fleas or metabolic disturbances (ie hyperthyroidism). Your vet may have a good moisturuzing spray that can help along with frequent brushing. However, it may be worth a basic blood test to make sure there is no underlying issue that could be slowing the desire to groom (ie kidney disease, hyperthyroidism, etc). I hope this helps and gives you direction.
Thank you so much for your reply and your questions. The area under her fur appears to be normal (not red, scaly or itchy) and I have not seen her react differently (more grooming, itching). As I brush her, there does seem to be more dandruff. Most of the fur is coming out on her hind-quarters/back of her hind legs.
She has limited outdoor visitation and she is always monitored when she is out (she has no claws). She does seem to drink more frequently from her bowl/my glass/the sink and spends more time at her chosen watering hole.
I hope this helps... Thank you!