Question about skin condition

I have a 10-year-old tortoishell/tabby shorthair that has recently started losing hair. All of a sudden about 5 weeks ago she lost most of the hair on her front legs. It almost looked as though they had been shaved. I took her to the vet: skin scrapings were negative, black light was negative, so vet gave her a steroid shot and I took her home. She grew most of the hair back, and then just now I noticed a new bald spot on one front leg and a new rather large bald spot on her side. I have not noticed her grooming excessively and the skin is smooth and blemish-free. No redness, no scabbing, no nothing. I am going to call the vet again tomorrow, but does anyone want to put any ideas out there as to what this may be? Alopecia?

Did the vet run a senior panel???

No, not yet.

I would start there .. many common "senior " issues can have that as a side effect