This could be caused by many things, but patchy focal areas of hair loss especially on the head are typical of localised Demodex infection. Demodex is a mite that commonly affects young Staffy-type breeds. One sometimes sees pustules, papules, or blackheads and areas of redness, but not always.
Demodex is something that is quite easily treatable but you would need to go to a vet. Your vet will likely perform skin scrapings to look for Demodex or other possible causes. Some cases do resolve on their own, but in other cases the infestation becomes much more severe.
Obviously nobody can diagnose the cause of your dog's hair loss over the internet. Recommendation to see a veterinarian is really the only advice to give online. If this has been going on for a long time it is unlikely to get better on its own.