OMFG... Get yourself to your general practioner and have him rule out other medical problems. Kidney problems, autoimmune diseases, liver problems, hormonal problems, and all kinds of other things can cause hair loss. Some of the stuff on that list can kill you.
Pardon me, but if your dermatologist hasn't put you through a full battery of tests to make sure that all your internals are in good working order or told you to see you GP to do so, then IMHO he's an f-tard! Find another doctor.