Skin & hair

The Newer Biologics Reaching for HS

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For years, adalimumab was the only biologic built and tested specifically for hidradenitis suppurativa. That is changing. Interleukin-17, the inflammatory signal already targeted by biologics used in psoriasis, has become a second pathway dermatologists reach for in HS that isn't answering to TNF-alpha blockade. Here is what IL-17 inhibition is, why the pathway matters, and where a newer biologic realistically fits against oral antibiotics, hormonal treatment, and surgery.

Last updated: July 2026

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What Drives the Inflammation in Hidradenitis Suppurativa

Hidradenitis suppurativa is a chronic inflammatory disease that produces painful nodules, abscesses, and tunnels under the skin, driven by immune activity around hair follicles rather than by hygiene, and that immune activity runs through more than one inflammatory signal 1. Adalimumab, the first HS biologic to earn its own approval, works by blocking tumor necrosis factor-alpha (TNF-alpha) and built that approval on two large placebo-controlled trials showing significantly more people responded to it than to placebo by twelve weeks 2. TNF-alpha was the first inflammatory signal in HS to have a drug built and tested against it specifically — not necessarily the only one that matters. Severity in HS is staged by how much skin is involved, whether tunnels have already formed under the surface, and how interconnected the lesions are, and that staging is what eventually points a clinician toward a biologic conversation at all, regardless of which inflammatory pathway the drug ultimately targets 3.

Why Interleukin-17 Became a Second Target

Interleukin-17 (IL-17) is an inflammatory signaling protein distinct from TNF-alpha, and it drives disease activity in several chronic inflammatory skin conditions. Dermatologists choosing among the psoriasis biologics already weigh TNF, IL-17, and IL-23 inhibitors against one another, since blocking IL-17 is a well-studied way to control inflammation in psoriasis when topical treatment and other systemic options haven't been enough 4. That established track record in a related inflammatory skin disease is a large part of why IL-17 blockade became a logical next pathway to test in hidradenitis suppurativa, rather than simply building a second TNF-alpha drug. The same IL-17 targeting approach carries treatment-guideline backing in psoriatic arthritis too, a related condition where it sits among several biologic options clinicians choose between depending on which joint and skin symptoms dominate — evidence that the pathway's usefulness extends beyond a single disease 5.

Secukinumab and Bimekizumab: What Sets Them Apart From Adalimumab

Secukinumab and bimekizumab are both IL-17 inhibitors, the same drug class already established in psoriasis and psoriatic arthritis, and both have moved into use for hidradenitis suppurativa as dermatologists look for options beyond adalimumab for the disease 4. Because they block a different inflammatory signal than TNF-alpha, someone whose HS doesn't respond to adalimumab is not guaranteed to fail an IL-17 inhibitor too — a drug that doesn't work on one inflammatory pathway doesn't reliably predict failure on a different one. Bimekizumab goes a step further and blocks two related IL-17 subtypes rather than one, though what that added breadth means for an individual person's disease is still something a treating dermatologist has to judge case by case rather than something a general article can promise. A drug's success in psoriasis is also not automatic proof of equal effectiveness in HS: the two diseases share inflammatory biology but are not identical, which is exactly why dedicated hidradenitis-specific evidence, not just borrowed evidence from a related disease, matters before treating the two as interchangeable.

Where a Newer Biologic Sits on the HS Treatment Ladder

A biologic of any kind is rarely a first treatment for hidradenitis suppurativa. The hs treatment ladder typically starts with antiseptic washes and topical antibiotics for limited, milder disease, moves through oral antibiotic courses for more active disease, and considers hormonal treatment for hidradenitis such as spironolactone in some patients, before reaching for a biologic 3. Staging matters here: it is what tells a clinician and patient whether the next reasonable step is a stronger antibiotic course, a biologic, or surgery for hidradenitis suppurativa when tunnels have already formed and won't respond to any drug alone, IL-17 inhibitors included. None of these steps are strictly one-directional, either — a person already on a biologic can still need a procedure for tunnels that formed before treatment started, and antiseptic and wound care typically continue even after a biologic is added rather than being dropped once a stronger drug enters the picture.

What Determines When to Start Biologic for Hidradenitis

Deciding when to start biologic for hidradenitis usually comes down to how extensive the disease already is — how many areas are involved, whether tunnels have formed, and how much topical and oral treatment has already been tried without lasting control 3. It is not a single symptom or a fixed number of flares that triggers the decision; it is a staging conversation between patient and dermatologist about how much the disease is already interconnected under the skin. Choosing which biologic to start with, adalimumab or one of the newer IL-17 inhibitors, is a separate decision from that timing question, and it often comes down to what has already been tried, insurance coverage rules such as step-therapy requirements, and how a person's disease pattern looks on examination. Newer drugs sometimes face more coverage friction simply because they are newer, which is worth understanding going in rather than discovering only after a prior-authorization denial.

What a Biologic, of Either Kind, Doesn't Fix

No biologic, TNF-alpha or IL-17 targeted, reliably closes tunnels that have already formed under the skin — that is a mechanical problem, not an inflammatory one, and drugs that quiet active inflammation don't undo scarring that already exists 1. Hidradenitis suppurativa also carries comorbidities a biologic doesn't address on its own, including a strong association with smoking and with obesity, so wound care, weight and smoking counseling, and treatment of any coexisting conditions tend to run alongside drug therapy rather than being replaced by it 1. A dermatology team managing HS well is usually coordinating more than one lever at a time, not relying on the injection alone.

Switching Between Biologics: What the Decision Usually Involves

When one biologic stops working or never worked, switching to a drug targeting a different inflammatory pathway is often the more useful move rather than simply stopping treatment altogether or assuming every biologic will fail the same way. Response is typically judged at a defined checkpoint rather than day to day, and screening for infection risk, including latent infections, before and during treatment is standard practice across this drug class generally — the specifics of what gets checked and how often are worth asking a prescriber about directly, since they vary by drug and by individual health history rather than being identical for everyone. A flare that appears while already on a biologic is also worth distinguishing from a new infection before assuming the drug itself has simply stopped working.

Common questions

Not necessarily. Adalimumab still has the longest track record and the original HS-specific trial evidence. IL-17 inhibitors like secukinumab and bimekizumab give dermatologists another pathway to try, particularly when adalimumab hasn't controlled the disease or has stopped working, rather than being positioned as a universal first choice over it.

Both are inflammatory signals implicated in hidradenitis suppurativa, but they are chemically distinct pathways. Adalimumab blocks TNF-alpha; secukinumab and bimekizumab block IL-17. Because the pathways differ, a person's disease not responding to one doesn't reliably predict how it will respond to a drug targeting the other.

Switching biologic classes after one hasn't worked, or has stopped working, is a standard part of managing chronic inflammatory disease. The decision involves a dermatologist reviewing how the current drug has performed, ruling out infection as a cause of a flare, and weighing insurance and monitoring requirements for the new drug.

No. IL-17 inhibitors work on active inflammation, similar to adalimumab, not on tunnels or scarring that already exist under the skin. Established tunnels typically need a procedural or surgical approach, sometimes running alongside a biologic rather than being replaced by one.

Drugs need dedicated trials in a specific disease before they can be used and approved for it — a biologic's success in psoriasis doesn't automatically prove it works the same way in hidradenitis suppurativa. IL-17 inhibitors reaching HS reflects that dedicated research catching up to a pathway already validated in a related skin disease.

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When an HS Flare on a Biologic Needs Prompt Attention

  • —Spreading redness, warmth, or fever around an HS lesion, which can signal infection rather than a typical flare
  • —A new fever, chills, or feeling seriously unwell while on any biologic
  • —New or worsening joint pain and swelling after starting a biologic
  • —A lesion that is rapidly enlarging, intensely painful, or draining foul-smelling pus

Spreading redness with fever, or any sign of serious infection while on a biologic, warrants same-day medical attention — urgent care, or the ER if symptoms are severe or rapidly worsening.

This article is general health information, not medical advice. It cannot tell you whether a newer biologic is right for your HS or replace an in-person evaluation by a dermatologist. Decisions about starting, switching, or stopping a biologic should be made with the clinician managing your care.

References

  1. 1.Sabat R, Jemec GBE, Matusiak Ł, et al. (2020). Hidradenitis suppurativa. Nature Reviews Disease Primers. doi:10.1038/s41572-020-0149-1 ✓Hidradenitis suppurativa is a chronic inflammatory disease with follicular/immune pathophysiology producing nodules, abscesses, and tunnels, driven by immune activity rather than hygiene; background for multiple inflammatory pathways and comorbidities (smoking, obesity) in the disease.
  2. 2.Kimball AB, Okun MM, Williams DA, et al. (2016). Two Phase 3 Trials of Adalimumab for Hidradenitis Suppurativa. New England Journal of Medicine. doi:10.1056/NEJMoa1504370The PIONEER I and II phase 3 placebo-controlled trials found weekly adalimumab significantly increased clinical response at week 12 in moderate-to-severe hidradenitis suppurativa, forming the basis for the first biologic indication in HS.
  3. 3.Alikhan A, Sayed C, Alavi A, et al. (2019). North American clinical management guidelines for hidradenitis suppurativa: Part I: Diagnosis, evaluation, and the use of complementary and procedural management. Journal of the American Academy of Dermatology. doi:10.1016/j.jaad.2019.02.067North American HS guideline on severity staging and evaluation, used here to support the treatment-ladder sequencing (topical to oral to biologic to procedural/surgical) and the staging-driven decision of when to escalate.
  4. 4.American Academy of Dermatology; National Psoriasis Foundation (2019). Joint AAD-NPF guidelines of care for the management and treatment of psoriasis with biologics. Journal of the American Academy of Dermatology. PMID 30772098 ✓AAD-NPF evidence-based recommendations establishing IL-17 inhibitors (alongside TNF and IL-23 inhibitors) as a validated biologic class for treating psoriasis; used here as background for why IL-17 blockade was a logical pathway to test in a related inflammatory skin disease.
  5. 5.Singh JA, Guyatt G, Ogdie A, et al. (2019). 2018 American College of Rheumatology/National Psoriasis Foundation Guideline for the Treatment of Psoriatic Arthritis. Arthritis Care & Research / Arthritis & Rheumatology. PMID 30499246 ✓ACR/NPF treatment guideline for psoriatic arthritis covering TNF-inhibitor and IL-17-inhibitor biologics among first-line options; used here to support that IL-17 targeting has treatment-guideline backing beyond psoriasis alone, in a related condition.

5 sources, numbered by first appearance. General health information, not medical advice. AI-assisted editorial content — citations link their sources. Editorial policy

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