Hidradenitis Suppurativa and the Skin Microbiome

What Is the Human Microbiome?

The human microbiome is a topic of great interest at the moment. Microbiome simply means all of the microbes that normally live in and on the human body. For example, much focus has been given to the gut microbiome and its effects on human disease such as inflammatory bowel disease.^[1] We are only beginning to look into the importance of the skin microbiome. Many dermatological diseases have been linked to changes in the skin microbiome, including acne, rosacea, psoriasis, and eczema.^[2] It is generally believed that a more diverse microbiome is associated with health, while a deficiency in diversity allows for dangerous bacteria to grow and take over. 

What Is Hidradenitis Suppurativa?

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease characterized by recurrent painful nodules and boils in areas where skin rubs together. HS affects young women more than men, and commonly occurs in the armpits, breast folds, and groin. Although the cause of HS is not fully understood, it is believed to be due to the blockage of hair follicles, leading to inflammation, abscesses, and scarring. 

What Role Does Bacteria Play in Hidradenitis?

HS is not caused by infection, though bacteria does seem to play a role in the disease process. One clue to the role bacteria play in the disease is the improvement patients have with antibiotics treatment. It seems that antibiotics are important in tackling the inflammatory component of HS and minimizing the pain and scarring. More recent studies have suggested that a disruption in the normal skin microbiome is linked to the disease. A study in Denmark found that patients with HS had an abundance of certain bacterial species when compared to control patients without HS, including Corynebacterium, Porphyromonas and Peptoniphilus species. Control patients also had a higher abundance of the bacteria Propionibacterium compared to people with HS. The authors concluded that there may be a link between the skin microbiome and HS, though more studies are needed to evaluate whether the link is directly causative.^[3]

What Does This Mean for Individuals With Hidradenitis Suppurativa?

As we continue to learn more about how the microbiome influences the development and progression of hidradenitis suppurativa, we can create better treatments. For example, treatments can target specific bacteria directly, either by restoring what is deficient, or eradicating disease-causing microbes. 

The skin microbiome has already been utilized for treatment of other skin diseases such as eczema. In 2017, Gallo and Nakatsuji et al. published the results of a study where they created a lotion containing bacteria normally found on healthy skin and applied it to those suffering from eczema. They found that application of the lotion resulted in an increase in the number of healthy bacteria, and the elimination of the “bad bacteria,” Staphylococcus aureus.^[4]

Unfortunately, we do not know enough about HS to begin designing targeted microbiome treatments. More studies are needed to determine the role of the skin microbiome in the disease process before we can begin using it to our advantage.