My mom had rapid hair loss and the dermatologist was NOT at all helpful. She diagnosed her with male pattern baldness after all her tests came back normal and sent her on her way. We do NOT have male pattern baldness in the family. My mom went to family doctors and even an endocrinologist. They tried low doses of synthroid (thyroid medicine) on her, along with other things, to no avail. My mom discovered on her own research that it was a medication she was taking that caused it. (It was a side effect, but not a common one) She also wasn't eating enough protein which didn't help her. Her hair has since grown back and its curly. (shes very happy about that) Are you on any medications? Are you eating a good balanced diet? Those are two factors that can make huge differences on hair growth and/or loss. All I can say is, be your own advocate. Sometimes docs have a hard time figuring it out.