Microbiome & Acne

We typically think of skin only as it relates to beauty — but it’s actually really important to our overall health, too. After all, it’s the largest organ in the body, and the major interface between us and pretty much everything outside of us. Our skin is also home to a vast array of microbes and research is just now beginning to piece together the important role they play in our health.

 

The skin microbiome is different all over our bodies. These “bugs” will vary depending on the amount of light and whether the area is moist, dry, hairy, or oily and will change with age and gender. For instance, a hormonal, sweaty teenage boy will have a completely different microbiome to say a more sedentary, postmenopausal woman.

The skin microbiome is different all over our bodies. These “bugs” will vary depending on the amount of light and whether the area is moist, dry, hairy, or oily and will change with age and gender. For instance, a hormonal, sweaty teenage boy will have a completely different microbiome to say a more sedentary, postmenopausal woman.

It is estimated that the average human has 1 trillion bacteria inhabiting their epidermis and hair follicles at any given moment. Skin microflora is typically non-pathogenic. In healthy dermal environments these bacteria are considered not harmful, or offer specific benefits including the prevention of transient pathogenic organisms from colonizing the skin surface.

 

pH Matters

The epidermis is naturally acidic (pH 4-4.5) as a result of lactic acid produced in sweat by skin microorganisms. In mildly acidic skin environments, mutualistic flora (microorganisms that produce a mutual benefit for host and bacteria) such as Staphylococci, Micrococci, Corynebacterium and Propionibacteria flourish. However, transient bacteria such as Escherichia, Pseudomonas, Staphylococcus aureus or Candida albicans will not grow or thrive. Antimicrobial substances secreted by the skin are enhanced in acidic conditions and thus, stop the growth of harmful bacteria. Research has shown when skin is in an alkaline state bacteria detach from the skin and are more easily discarded from the dermis.

In vitro, Propionibacterium acnes (P. acnes) have been found to flourish at pH values between 6 and 6.5, whereas its growth is considerably decreased at pH values less than 5.5. Researchers conducted a randomized, open, comparative three month trial assessing the use of acidic, or conventional soap in the prevention of acne lesions in acne-prone patients.

Participants were asked to apply an acidic soap (syndets) or an alkaline/conventional soap to facial skin for 1 minute in the morning and in the evening. This study evaluated 120 adolescents and young adults who had been diagnosed with inflammatory acne lesions. The participant’s inflammatory acne lesions, itching, redness, and scaling were evaluated and analyzed.

 

 

The alkaline/conventional soap participant group had an increase in inflammatory lesions, while the group using the acidic soap found their inflammatory acne lesions to decrease to statistically significant levels. The alkaline/conventional soap participant group reported a 40.4% increase in symptoms of irritation whereas the mildly acidic soap group experienced only 1.8% in symptoms of irritation. The researchers stated that the number of inflammatory acne lesions is clearly lower when an acidic soap is regularly used for cleansing the face as compared to an alkaline/conventional soap. This also proved to be the case with other types of topical skincare products.