October 12, 2026

HS Is a Systemic Disease. The Evidence Base Has to Reflect That.

By Amit Garg, MD, Secretary, HS Foundation; Founding Chair, Department of Dermatology, Zucker School of Medicine at Hofstra/Northwell

For a long time, hidradenitis suppurativa was thought of primarily as a chronic skin disease. Dermatologists caring for HS patients recognized that these patients were also carrying a substantial burden of other medical conditions, but there was no way to systematically prove it. The patient populations were too small, the data too scattered, and the observations too anecdotal to move beyond individual clinical impression.

That began to change about a decade ago. When Big Data analytics platforms became capable of combining large HS patient populations with granular clinical information, we could finally make observations that were meaningful clinically and biologically. What has emerged from that work has changed how those of us who care for HS patients think about the disease. Nearly every organ system in the body can be related to inflammation in HS independently. Some involvements are more common than others, but the pattern is consistent enough, and independent enough of other risk factors, to reframe what HS is.

What this means for clinicians

The immediate implication is that treatment strategy has to take a patient's comorbidity profile into account. The therapies we consider for HS interact with the other medical issues a patient is carrying, and choosing the right approach for the person in front of us requires understanding the full picture of their health.

There is a second implication that is less obvious and, over time, may matter more. The dermatologist is not going to be the central figure managing every comorbid condition an HS patient carries. That is not the model. But the dermatologist is often the clinician who has the earliest, clearest view of that patient's overall inflammatory burden. That puts us in a position to advocate with primary care and with other specialists for early identification of conditions that, if caught in time, can be mitigated before they become chronic and disabling. That advocacy role is part of what modern HS care requires.

What this means for payers

The comorbidity picture also changes how coverage decisions should be evaluated. Conditions like obesity, metabolic disease, diabetes, and cardiovascular disease are not academic categories. When they go unrecognized and unmitigated, they lead to serious chronic health problems, disability, higher utilization of care, and in some cases increased mortality. Identifying them early and managing them meaningfully reduces the downstream cost.

Managing HS well is upstream of a set of conditions that carry significant systemic cost. The financial argument for early, adequate HS care compounds when it is understood alongside the diseases it can help prevent or delay. Payers looking at the direct cost of HS therapies in isolation are looking at only part of the ledger.

Why the evidence base is harder to build than it looks

None of this changes patient outcomes without a better evidence base than the one the field has today. That evidence base is harder to build than it looks.

The core problem is that we do not yet measure response to HS treatment in a way that fully works for everyone involved. The measurement should be meaningful to patients. It should be reliable for investigators. It should be defensible for regulators who ultimately determine whether a therapy is approved. The primary instrument currently used in HS clinical trials, the HiSCR, has real limitations on all three fronts. It does not capture response on draining tunnels, which are among the most symptomatic lesions a patient can have. A HiSCR 50 response, which sounds like an improvement on paper, often does not correspond to the patient feeling meaningfully better. Patients tell us this directly. They say, thanks, I feel a little better, but my life is still turned upside down.

The instrument also asks investigators to do something intrinsically difficult. Counting individual inflammatory lesions accurately, distinguishing them from other lesion types, and doing that consistently across visits and across raters is a task human beings are imperfect at. The data on how consistently the same investigator scores the same patient is not encouraging.

The consequence is that drugs with strong translational premise and strong phase 2 data can still fail in phase 3. It is close to a coin flip whether a good drug for HS makes it through. That should not be the case. The field is actively working on three fronts to fix it: digital tools that help investigators apply the current framework more accurately, new measurement instruments designed to better capture what matters to patients while meeting regulatory rigor, and lessons learned from every trial, whether it succeeds or fails.

Where the guidelines fit

The upcoming joint AAD and HSF guidelines are one piece of a larger ecosystem. The measurement framework used in trials informs the level of evidence assigned to each therapy. The therapies backed by that evidence are what the guidelines synthesize. The patient's individual comorbidity profile then informs which of those therapies makes sense for the person in front of us. Each element depends on the others.

The guidelines themselves are a real-time snapshot of a fast-moving field. The pace of therapeutic development in HS has been rapid enough that a snapshot published today would risk being partially obsolete within a year or two under the old five-year revision cycle. The live-update mechanism built into these guidelines is what allows them to stay current with the pipeline rather than fall behind it.

For all the infrastructure the guidelines represent, the outcome patients need most over the next two to three years is that the late-stage drug development programs currently in the pipeline succeed. That success is not guaranteed. It depends on patients continuing to lend their trust to trials, on sponsors continuing to invest in innovation, and on the investigator community continuing to run trials with the rigor meaningful evidence requires.

The field has made real progress in understanding HS as the systemic disease it is, in mapping its comorbidity profile, and in improving how it builds evidence for the therapies that treat it. All of that work has one purpose. We need to make the lives of our HS patients far better than where they are today.

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