Researchers have found that a common acne medication has the potential to alter the microbiome of the skin, raising the possibility of developing microbiome-based acne treatments.
Isotretinoin, a form of vitamin A, has been prescribed to treat acne for decades. It reduces oil production in the skin, which helps prevent acne from forming.
The new research from Washington University School of Medicine in St. Louis showed a previously unknown benefit of the medication. It shifts the skin microbiome of acne patients to more closely resemble that of people with normal skin.
According to the researchers, there is a need for microbiome-based acne treatment alternatives because isotretinoin causes severe birth defects, so doctors must take added precautions for women of child-bearing age.
Doctors often prescribe antibiotics that target bacteria called Cutibacterium acnes - also called Propionibacterium acnes - which is associated with acne.
But such antibiotics can contribute to the development of resistant strains of bacteria and can kill off potentially beneficial microbes as well. Isotretinoin is not an antibiotic.
It is largely thought to treat acne by drying out the skin, making it a less inviting place for acne-causing and acne-promoting microbes to flourish. It is the only therapy that can reliably clear acne long term.
"There are greasy areas of the skin that support the growth of certain communities of bacteria, and we know that some of them appear to be associated with acne," said lead author William H. McCoy, an instructor in medicine and a dermatologist.
"We asked whether we would see fewer of those bad bacteria on the skin after isotretinoin treatment, and we did. But we also know that this drug doesn't work on the bacteria themselves. It changes the patient's skin.
"So if the microbes are changing, it's in response to changes in the patient's skin. The drug appears to make the skin less hospitable to acne-causing bacteria," McCoy said.
The results were published in the Journal of Investigative Dermatology.
The team studied bacteria sampled from facial skin swabs at four time points over the course of the 10-month study.
They found that isotretinoin therapy increased the diversity of microbes found on the skin.