Diagnosis of both Acne and Pityrosporum folliculitis

Dear Doctor,
I am an almost 30 year old female and recently went to the dermatologist for the first time after experiencing what I thought was mild, but persistent acne on my chest and back for a few years (not on face).

After visually examining my symptoms for a couple seconds, the dermatologist concluded that I have both acne and Pityrosporum folliculitis (caused by yeast overgrowth on skin).  She perscribed Doxycycline (20mg, twice/day) tablets and also a 2% Ketaconazole shampoo to wash my chest and back with once per day.

I was under the impression that an antibiotic will make the yeast overgrowth worse and am confused by this recommendation. I realize the antibiotic is for the "acne" symptoms and the other for the yeast overgrowth, but I'm wondering if I should seek a second opinion before continuing with this treatment for the next few months.  Without swabbing the folliculitis, how would one know if it is caused by yeast or bacteria?

Thank you in advance for your help.
Jennifer

[Alan Rockoff, MD]

Acne and folliculitis look about the same.  I think your dermatologist wants to cover both bases, which is not unreasonable.  Both conditions are usually diagnosed clinically, without the need for cultures unless no response is obtained.  Pityrosporum yeasts are not the same kind of yeasts that overgrow when you take antibiotics.  Pityrosporum lives in everyone's follicles and sometimes causes bumps, so you needn't worry that the antibiotic will undo the effects of the antifungal treatment.  You should discuss these questions with your dermatologist directly.

Best.

Dr. Rockoff