Scalp problem

Hello,
I am 30 years old. I have been suffering from some kind of scalp infection for nearly 15 years now. I contracted this condition from one of my friends who said he was suffering from dandruff. For nearly 14 years I have been trying all kinds of shampoos and other non prescription applications to get rid of the problem. But the condition has persisted. All this time I have had itching in my scalp at times had severe bumps all over my head (generally more on the back side). I have had acne all over my face, sometime very large. These have left my cheeks completely scarred. This condition has also affected my shoulders and to much smaller extent my chest, where acne like bumps have been appearing all along and have left the areas dotted with scars. All along I have had continuous itching with accompanying hairfall. About 7 years ago I started using Proactive solution for treating the acne on face and it worked perfectly and I did not have any acne on my face as long as I was using it. But I have moved to a different country and do not get Proactive here. My acne have returned and are leaving even more craters on my cheeks.
About 6 months ago I finally visited a dermatologist who said that I had sebohorreic dermatitis and put me on a course of antibiotics, steroid lotions and shampoos (azythromycin, doxycycline, minocycline hydrochloride,nizral ,fluconazole, betamethasone dipropionate, ketoconazole and pyrithione zinc shampoo). I was on the antibiotcs for roughly 3 months. My acne cleared within a month and my scalp seemed to have cured to about 80%. I continued on minocycline hydrochloride for another 2 months. But once I have gotten off the antibiotics my acne have returned, after about 1.5 months, and my scalp is itching as badly as before and am having a lot of hairloss. I am not sure what is to be done as the doctor says that it is not good to go back on antibiotics again. Currently, I am using the steroid lotion and ketoconazole shampoo only. Please advise, what can be done so that I can get cured of this long and traumatic experience.

thanks
kris