Dear Doctor: I heard two teenagers in line at the drug store talking about the skin microbiome and how you shouldn’t use soap on your face because it wipes out the good bacteria. We hear a lot about the gut microbiome lately, but is the skin microbiome really even a thing?
Dear Reader: The word “microbiome” refers to any community of microorganisms that live together peaceably in a specific environment. To reflect the fact that they don’t cause illness, it’s said that they “colonize” an area rather than “infect” it.
In terms of the human microbiome, we’re talking about the vast array of microbes that live upon and within our bodies. These colonies are typically composed of bacteria, bacteriophages, fungi, protozoa and viruses. Depending on their location, they number into the millions, billions and, in the gut microbiome, trillions.
In addition to the gut, anatomical sites of distinct microbiomes in and on the human body include the nose, mouth, esophagus, lungs, genitals and even the hidden depths of the belly button. And, yes, the skin, which is often referred to as the largest organ in the body, is the site of a microbiome. Multiple ones, in fact. They differ depending on their specific locations, and are affected by the variety of environments they interact with, including oily, moist and dry.
For instance, the skin between your toes, which spends long stretches of time in the moist darkness created by socks, shoes and perspiration, hosts a different profile of microbes than does the skin on your scalp, behind your ears or on the backs of your hands.
The epidermis, which is the top layer of the skin, is a tough environment for microbes. It’s dry, acidic and low in nutrients, and great swaths of it are exposed to the elements. And, yet, millions of bacteria, viruses and fungi find a way to make it their home. Depending on their location, they survive on the available proteins, oils, salt or moisture. Research shows that, as with our gut, many of the microbe colonies on our skin play a role in fending off potential pathogens. They also play a role in wound healing, in maintaining skin’s overall health and in how we smell. All of which is good reason to take a look at our bathing and skin care routines.
Dermatologists have long suggested that harsh soaps, too much scrubbing and daily bathing with overly hot water can strip the epidermis not only of helpful oils, but also wreak havoc on beneficial microbe colonies. To protect your skin’s microbiome, think in terms of gentle, pH-balanced soaps, and gentler overall treatment. That means save the scrubbing with loofas and brushes and other rough materials for the truly grubby areas. Instead of a vigorous rubbing with a towel when you are finished bathing, gently dab and pat your skin dry. And, in case you were wondering, you definitely want to keep up the vigilant hand washing that helps keep us safer during the coronavirus pandemic.
(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)