8 Must-Know Facts About Biofilms & Hidradenitis Suppurativa

Dealing with the painful skin condition is tough, but slick layers of bacteria known as biofilms can make it even tougher. Here's what scientists are discovering about the interaction between the two.

by Benedict Cosgrove Health Writer

It may not be the most common skin disease (it affects about 1 percent of the global population) or the easiest to roll off the tongue. But if you suffer from hidradenitis suppurativa (HS), you don’t need anyone to tell you that it’s definitely one of the most painful. “HS is characterized by large, inflamed boils in areas like the armpits, groin, and breast area,” says Rashmi Unwala, M.D., a dermatologist at the Cleveland Clinic in Cleveland, OH. If that doesn’t sound like a world of hurt, now add this: Those boils can often burst, leading to a tunneling effect under the skin, inside of which biofilms can form.

Biofilms, slimy layers of bacteria that adhere to wet surfaces, are highly resistant to antibiotics—a worrisome prospect for HS sufferers who rely on long-term courses of the drugs to keep their condition under control. In fact, a recent study by the European Academy of Dermatology and Venereology found that biofilms significantly reduced people’s sensitivity to tetracycline and clindamycin, two standard antibiotics in the treatment of HS.

While scientists are still learning about the role biofilms play in the development of HS, there are some key findings that anyone dealing with this challenging disease should know.

#1. HS Itself Is Still a Mystery

The questions surrounding HS, from what causes it to which medical discipline should "own" it, are all too familiar to those struggling with the disease. Small consolation, but it’s a headscratcher for researchers, too. "There's a logical reason we don't know a lot about HS," says Haley Naik, M.D., an assistant professor of dermatology at the University of California, San Francisco and founder of the UCSF HS Clinic. "For as long as we've known it exists, there's been a dearth of studies and funding focused on it. The amount of research published on HS over the past 20 years is minuscule in comparison to that published on other prevalent inflammatory skin conditions. It is a truly neglected disease."

#2. It’s Quite Sweaty

HS, which typically first appears after puberty, is most likely to occur in areas of your body with where skin-on-skin friction occurs, like your armpits, under the breasts, and genital region. Scientists believe the skin lesions begin to form due to inflammation around hair follicles that become tender and swollen. These can then fill with pus and blood and may be extremely painful. Obesity and smoking appear to factor into the development and severity of HS , though many patients of normal weight that have never smoked also develop the disease. There may also be a genetic component to the disease, as 30% to 40% of people with HS also have a family member with the condition.

#3. The Biofilm Factor Is a Hot Debate

While research suggests that there is a meaningful connection between HS and biofilms, the exact sequence of events is up for discussion. “We now have a handful of studies that have looked at biofilms and HS,” says UCSF's Dr. Naik, “and I think we can say with pretty good certainty that biofilms exist in sinus tracts [the pus-filled 'tunnels' beneath the skin in HS sufferers], because these tracts are filled with bacteria, and of course they'll try to protect themselves by making this material that we commonly call biofilms.”

But are they the cause or the result of this inflammatory condition? “We need to do more work on what's the chicken, and what's the egg,” she acknowledges. “Does the inflammatory response come first, and the bacteria are secondary? Or do the bacteria end up somewhere they're not supposed to be, and that incites the robust inflammatory response?” Some data indicate that biofilms are not present in early lesions but form later to play a role in disease maintenance. Either way, once they are in place, it throws a wrench into treatment.

#4. Biofilms Mess with Antibiotics

Biofilms are actual structures made up of proteins, fats, and other materials. They are gooey substances, like the mucus in your nose, bacteria discharges these materials and form the biofilm to protect themselves, protecting the germs from anything trying to remove it—namely, antibiotics. In the case of HS, this structural slime effectively seals the bacteria inside the tunnels that have formed under your skin, preventing antibiotics from reaching them to kill them off, according to researchers at the Centre of Biomolecular Sciences, University of Nottingham in the UK.

#5. Biofilms—They're Not Just for Humans!

Wrapping your mind around what biofilms actually are can be tricky, in part because the variety, both bacterial and fungal, is so vast. In fact, biofilms don’t even have to occur on people—they have been known to form on industrial products like drain pipes and medical devices, as well as plants. The slime-encapsulated bacteria colonies are at the heart of many chronic infections and conditions ranging from urinary-tract and middle-ear infections to gingivitis. (You know that slimy gunk that forms on your teeth when you haven’t brushed them all day? That’s a biofilm!). And biofilms also contribute to more serious illnesses like endocarditis.

#6. Technology Is Getting Better at Spotting Them

Not every person with HS will develop biofilms. But—as with virtually everything about hidradenitis suppurativa—treatment outcomes may improve if biofilms are identified early, since it indicates to doctors that antibiotics may not work as well, and other approaches to treating HS could be more effective. There are numerous methods of detecting biofilms in HS, including tissue-culture plates (staining cells with crystal violet dye); a bioluminescent technique based on the signals of certain metabolically active cells; scanning electron microscopy, used to study the structure and number of bacteria in a colony; and confocal scanning laser microscopy, which provides a three-dimensional view of the microbial community. These cutting-edge detection techniques have greatly improved the medical community’s understanding and ability to identify the presence of biofilms.

#7: Research Is Ramping Up

There is currently no single treatment available to remove biofilms in people with HS. That’s partly because the variety of existing biofilms is huge (so there will never be a one-size-fits-all plan), and partly because biofilms have evolved over eons with the express purpose of protecting their precious cargo, so they’re not going down without a fight. Still, researchers are increasingly discovering approaches that show promise. For example, scientists at the University of South Florida in Tampa have found that a compound that they dubbed "darwinolid," found in an Antarctic sea sponge, appears to be effective in preventing the formation of a biofilm for methicillin-resistant Staphylococcus aureus—or as the rest of us know it, a staph infection that can cause pneumonia or even heart failure. Another potential tactic might be to use biologic agents, electrical impulses, or other means to disrupt, block, or scramble the chemical signals that cells within a biofilm use to communicate with one another.

#8: Treatment Is Still Evolving

Bottom line? The exact relationship between hidradenitis suppurativa and biofilms remains unclear, even as researchers seek new approaches for disrupting—and even preventing their development in those living with HS. Because treating biofilms directly is still an ongoing area of research, for now the majority of treatment options focus on HS itself. These include antibiotics (with the understanding that at some point the effectiveness might diminish) as well as the FDA-approved biologic drug Humira (adalimumab).

Another approach involves "unroofing," or removing skin tissue in the affected area to expose the tunnels beneath the skin and allow pus to drain, thereby relieving the pressure that is such a painful part of the disease for so many patients. In advanced stages, your doctor might suggest surgical removal of the affected areas, a procedure that in some cases include prolonged wound healing and skin grafting.

While HS remains a challenging condition to live with, the ongoing research into biofilms may one day yield more effective treatment strategies for those dealing with the disease. Until then, talk with your doctor about the best plan to keep yourself one step ahead of HS.

  • Reduced sensitivity to antibiotics: Journal of the European Academy of Dermatology and Venereology. (2019). “Biofilm production and antibiotic susceptibility of staphylococcus epidermidis strains from hidradenitis suppurativa lesions.” ncbi.nlm.nih.gov/pubmed/30022542
  • Biofilms and endocarditis: Seminars in Thoracic and Cardiovascular Surgery. (2016). “Current hypotheses in cardiac surgery: Biofilm in infective endocarditis.” ncbi.nlm.nih.gov/pubmed/27568136
  • What are biofilms: British Society for Immunology. (n.d.) “Biofilms and Their Role in Pathogenesis.”
  • Detection of HS: Virulence. (2018). “Strategies for Combating Bacterial Biofilms.” ncbi.nlm.nih.gov/pmc/articles/PMC5955472/
  • Biofilms and resistance: Cold Spring Harbor Perspectives in Medicine. (2013). “Bacterial Biofilms: Development, Dispersal, and Therapeutic Strategies in the Dawn of the Postantibiotic Era.” ncbi.nlm.nih.gov/pmc/articles/PMC3683961
  • Biofilms and HS: FEMS Immunology & Medical Microbiology. (2012). “Considering Hidradenitis Suppurativa as a Bacterial Biofilm Disease.”
Benedict Cosgrove
Meet Our Writer
Benedict Cosgrove

Benedict Cosgrove has been a writer and editor since the mid-1990s, working on sites ranging from Wired's Netizen to the National Magazine Award-winning LIFE.com. He has written for the New York Times, Washington Post, Los Angeles Review of Books, Columbia Journalism Review, Daily Beast, CNN.com, and others; edited Covering the Bases and Gluttony (both from Chronicle Books); and is the author of Nothing Bad Ever Happens. See more of his writing at bdcwrites.com.