thin hair but want to take testosterone

[Karen]

Dear Dr. Redmond,

I'm 30 years old, and my hair started thinning when I was about 16. As my testosterone and DHEA levels are on the low end of the range, I thought I must be sensitive to what little testosterone I do have. On the other hand, I've always had far less body hair than average, and no underarm hair. Could one be oversensitive to testosterone on the head, and undersensitive to it on the rest of the body? I should also mention that when I was 26 I was diagnosed with a microadenoma (prolactinoma) and given cabergoline, and since I've been on this medication I finally started having mild underarm hair, with the existing body hair slightly increasing as well.

My second question is this: I've suffered from vulvar vestibulitis for the past 12 years, and have tried every available treatment except surgery. Recently I've heard about success with a topical compound of testosterone and estrogen, and am very eager to try it (I seem to fit the profile of hormone related VVS). According to articles I've read, in very low dosage this should not cause alopecia, especially in someone like me with little testosterone to begin with, but I'm still worried. How long in your experience does it take for low dosages of topical testosterone to start causing hair loss in women prone to it? And would it be possible to use a topical product that blocks testosterone on the scalp only, like men do?

Thank you very much in advance for your help!