Is this acne or a yeast-type infection?

My daughter, 21, has had bad acne for a long time, since she was 13 or so, and it has gotten progressively worse over the years in spite of treatment by a dermatologist, (and then, when she was uninusured) a couple of years of Proactive, and now that she's insured again, by her regulare doctor with minicycline and A-retin cream (since this past August).  It looks a little better sometimes, and sometimes not.  

It has been suggested to me that her condition looks more like a yeast-type infection:  more of blotchy, angry, red, raised areas than discrete "pimples" that come to a head (although there are some of those).  As a young child, she took a maintenance dose of antibiotics for years because of recurring UTIs, and the thought is that the balance of probiotic bacteria in her body has been affected (even though, at the time, I tried to make sure that she had regular doses of acidopholus -- but who knows? Maybe not enough?  Not consistent enough?  Not good enough quality product?)

Recently, she has developed a couple of scaly, rashy patches on the sides of her neck.  She said they were itchy at first, and that's how she noticed them.  Also, by the way, the condition on her face also extends down onto her back and somewhat on her chest.

I'm wondering if the antibiotic approach is just not the right one, and if maybe she should explore the possibility that it   actually is a yeast condition.  Is there a way to test this?  How would you suggest beginning to treat this?  It seems to me that probiotics would be a good idea anyway, since she's taking regular antibiotics, but should she look at other therapies?

I'd appreciate hearing your thoughts on this.

[loiloi]

Hi. Acne is caused by a sensitivity to the effects of androgens (male hormones which occur in male and female bodies). Androgens stimulate the sebaceous glands in the skin. Bacteria on the skin feeds off this excess oil, blocking the pores and leading to inflammed acne spots. Her doctor or dermatologist will be able to diagnose acne from visual presentation.
Has she tried an anti-androgen contraceptive pill such as Diane35 or Yasmin? These block the action of androgens on the skin. In addition to this, an anti-androgen medicine called Spironolactone can be taken.
If her skin gets irritated, Differin (adapalene) may be a better choice than Retin-a. Using a bland cleanser such as Cetpahil or La Roche-Posay will prevent irritation during treatment with topical retinoids.
Patients who do not respond to standard treatments (antibiotics, topical retinoids, anti-androgens) may warrant Oral Isotretinoin (Accutane).
Eloise.