Yup, sounds like Alopecia . My wife had it a couple of years ago. I was the first one to notice a couple of bald spots at the back of her head. Not easily noticeable as covered by surrounding hair.
When I told her and I showed her pictures it freaked her out . Went straight to a doctor recommended by a friend and the doctor gave her some tablets and topical lotion which did the trick.
The lotion was RETEN ( which is a generic of Minoxidil )
Doctor also recommended Baby Mild shampoo , as not too many chemicals.