Severe acne: what role does the skin microbiota play?

The mechanisms causing severe acne, which affects 20% of patients with acne, are still poorly understood by scientists. One avenue of research: Cutibacterium acnes (or C. acnes, formerly called Propionibacterium acnes) is a bacterium that could play a role in its development. But not necessarily in the way we might think....

 

Acne is a true affliction dreaded by teenagers that affects up to 85% of the population aged between 11 and 30. This inflammatory skin disease, which may be more or less severe, affects several parts of the body, from the face to the back. Is it the skin microbiota’s fault? According to research it is, although the bacteria responsible for severe acne have not yet been identified. French researchers have thus led their own study...with surprising results!

Less abundant and diverse microbiota

The skin microbiota of 24 patients, collected from their back (severe acne area) and face (mild to moderate acne), was compared to that of 12 healthy volunteers. Compared to controls, the back of patients hosted less bacteria, and it had a higher content of Enterococcus, among others; and in their faces, staphylococci were significantly more abundant, contrary to bacteria from the Propionibacteriaceae family which were less abundant in people with acne but more abundant in healthy people. The Propionibacteriaceae family thus seems to be a marker of healthy skin... This is a true paradox since C. acnes, which was known to be one of the bacteria responsible for acne, is part of this family!

A matter of balance

Acne thus seems related to a disruption of the skin microbiota (or dysbiosis), and its severity to a decreased bacterial diversity and abundance. According to the authors, more than the overabundance of C. acnes, it is the imbalance between the Propionibacteriaceae and the staphylococci families, competing with each other, that induces changes in skin pH and triggers the inflammatory process. This discovery opens the way to the development of new anti-acne treatments based on the restoration of skin microbiota: the skin would have an improved quality and then be able to prevent colonization by opportunistic bacteria.

 

Sources:

Dagnelie MA, Montassier E, Khammari A et al. Inflammatory skin is associated with changes in the skin microbiota composition on the back of severe acne patients. Exp Dermatol. 2019; doi.org/10.1111/exd.13988