"There are about 100,000 bacteria per square centimetre on the surface of the skin, and these are made up of 200-300 different types of bacteria. The theory is that when the skin is diseased, there is less diversity of bacteria — as happens with the gut," says lead researcher Richard Gallo, a Professor of Dermatology at the University of California San Diego. Reduced bacterial diversity may result in microbiome imbalance, Gallo says.
To test this, Gallo and his colleagues extracted samples of these good bacteria from the arms of five eczema patients and mixed them into cream. Reintroducing the cream to the faces of eczema patients significantly reduced the proliferation of S. aureus. However, Gallo notes that bacteria may not be the only cause of eczema in patients. Atopic dermatitis may be caused by genetics, which can make the skin more susceptible to flare-ups, and by bacterial balance, according to Gallo.
A similar study on probiotics reveals that applying a skin solution containing five percent lactobacillus helps relieve mild acne in patients. The results are published in the Journal of Cosmetic Science. Another study shows that consuming probiotics may help prevent and treat skin conditions by mitigating gut inflammation. Gut inflammation is shown to trigger the flare up of certain skin conditions such as acne and rosacea.
Dr. Miriam Wittmann, an Associate Professor of Inflammatory Skin Diseases at the University of Leeds, says the results of the recent study have significant implications. The treatment's potential may not be cure per se, but rather prevent the onset of flare-ups once the skin is stabilized. The therapy would prove beneficial as flare-ups may result in antibiotics-based treatment. Antibiotic treatment is shown to induce resistance, so it would be better to use them less often. Immunosuppressants may also help ease flare-ups, but can contain unwanted side effects. Using a person's own bacteria to mitigate the effects of acne is safer, Dr. Wittman stated.
Similar probiotic-based therapy have produced varying effects depending on the skin complaint, according to Dr. Carsten Flohr of the British Association of Dermatologists. "Whereas with eczema we think the bacteria might have a preventative role, with acne, the bacteria play a different role. The inflammation that occurs with acne is partly due to the presence of bacteria and the skin overreacting to that. However, there are other factors — such as hormonal changes in adolescence that increase the amount of oils produced in the skin," Flohr said.
According to Flohr, the skin is a highly complex environment, and the bacteria thriving in it adapts well to its environment. Having said so, it is better to use bacteria that are already present in the skin instead of introducing various bacterial types. Using bacteria to relieve these skin issues is a realistic practice, Flohr added.
When asked about avoiding face and hand washing to promote the balance of bacteria, Gallo confirms that standard hygiene shows no apparent effect on the composition of the microbiome. With the skin microbiome being important, humans would not have evolved to have it easily affected by outside factors such as washing, Gallo adds.