one possibility would be tinea capitus (ringworm of the scalp). another possibility could be a small area of alopecia. assuming you are not inadvertently pulling out patches of your hair by twisting or nervousness these are the two most common causes of patchy baldness. in order to be properly diagnosed and treated you would need to see a medical provider or dermatologist for a careful examination
i have a quarter size totally bald circle on the back of my head. what is causing this?