Hello and thank you for your question.
Is she currently on any flea prevention
Ok,
The base of the tail, lower back and back legs are the most common areas effected by fleas. You do not need to be able to see them for them to be present.
Since she lives outside I would recommend putting her on a flea prevention. I would recommend purchasing a quality flea prevention such as Advantage. This can be purchased at your vets office or some pet stores.
I would not recommend an over the counter flea prevention as these are often ineffective and have the highest rate of toxic reaction especially in cats.
Fleas can also pose serious health risks for your kitty such as tapeworms or anemia.
If fleas are the problem as I suspect you should notice a difference within the first month.
Should the problem not correct itself after flea prevention I would recommend having her seen by a vet to rule out skin infection or mites.
I hope you girl improves soon. Please feel free to reply back if I can be of additional assistance.
Candy
Technician
Practicing Veterinary Technician for 23 years. Veterinary Practice Owner, Technician Trainer