Richard Gallo, MD, PhD: The Skin Microbiome, Bacteriotherapy for Atopic Dermatitis

Published on: 

In an interview with HCPLive, Gallo described his AAAAI presentation on the function of the skin microbiome, as well as the microbiome’s connection to atopic dermatitis.

In his interview with HCPLive at the American Academy of Allergy, Asthma & Immunology (AAAAI) 2023 Annual Meeting in San Antonio, TX, Gallo described new research on the skin microbiome, atopic dermatitis (AD), and bacteriotherapy.

Gallo currently serves as a Distinguished Professor and as the Founding Chairman of the Department of Dermatology at the University of California, San Diego.

He is most well known for his discovery of the existence of antimicrobial peptides found in mammalian skin, as well as his research’s profound effects on knowledge of skin diseases such as rosacea, acne, and AD.

“My lab is interested in host pathogen interactions,” Gallo said. “And over the last decade or so we've been particularly focused on understanding microbes on the skin that are not pathogens, but have evolved with humans to provide host defense purposes.”

Gallo and his co-presenters’ talk was aimed at new developments in the scientific community’s understanding of the ways in which microbes inhabiting the skin can affect a host’s immunity and affect allergic inflammation outcomes.

“There's an evolutionary biology concept called the holobiont, which recognizes that an individual is really the sum of the genetic contributions of both the host as well as the microbes that live in it and on it,” he explained. “...What we've learned over the years is that there are a number of specific gene products made by both the human side and the microbe sides that interact.”

Gallo added that this complex interaction between varying cell types affects such processes as human diseases and that his team’s focus was AD.

“Current evidence suggests that some microbes on the skin, such as staph aureus and staph epidermidis, drive the flares of this disease,” he said. “It doesn't cause atopic dermatitis. But in a Th2 immune environment, the flare of disease is driven by the abnormal microbiome.”

Gallo and his co-presenters had explored the ways in which systemic antibiotic exposure can affect the long term composition of the microbiome, as well as new insights into a topical bacteriotherapy for AD.1

“So we've been studying that in mouse models, and then more lately in human clinical trials, showing how really rational selection of specific bacteria that live in healthy human skin can be used as a biotherapeutic to help improve health in atopic dermatitis patients,” he said. “We're still very much in early phases of our clinical trial work, we're in phase 1, which is clinical safety and so forth.”

To learn more about his AAAAI presentation, view Gallo’s full interview segment above.


  1. Nakatsuji, T., Hata, T.R., Tong, Y. et al. Development of a human skin commensal microbe for bacteriotherapy of atopic dermatitis and use in a phase 1 randomized clinical trial. Nat Med 27, 700–709 (2021).