Preauricular (which literally means before the ear) alopecia (hair loss) is a normal condition in many cats. When I was practicing, owners used to bring their cats in to the vet clinic thinking their cat had a skin disease. It’s often not real noticeable in kittens but between one and two years of age is when owners usually notice this condition.
With preauricular alopecia, there is a sparseness or thinning of the hair between the eye and the ear (the temple area). It is unrelated to breed, sex, or age. It shows up better in black cats or darkly colored cats.
My cat Bigfoot had this condition. He was a dark gray and white cat so it showed up well in his dark gray hair. Here is a picture.
See the baldness between Bigfoot’s eye and ear? This is a good example of preauricular alopecia. And it is perfectly normal. There is no treatment because this is not considered a pathological condition. It is often misdiagnosed as ringworm, allergies, mange, etc. If a cat with this condition were scratching the area or there is redness or scabs present, then diagnostic tests should be done to rule out other skin conditions. Otherwise, it’s a perfectly normal condition.