Secukinumab for Paediatric HS: A First for a Neglected Disease

The important number on the label is twelve

On 13 March 2026 the FDA extended the hidradenitis suppurativa indication for secukinumab to patients aged twelve and over weighing at least thirty kilograms, with dosing scaled to weight. It is the first IL-17A inhibitor available to adolescents with the disease.

As pharmacology this is a modest event — the same antibody, blocking the same cytokine, in a smaller person. As a statement about how HS gets treated, it is considerably larger, because the disease has spent decades being managed as though it began in adulthood. Novartis's own announcement puts the epidemiology plainly: HS affects as many as one in a hundred people worldwide, more than half of patients develop symptoms during adolescence, and it takes up to ten years on average to reach a correct diagnosis.

Hold those three facts next to each other. A disease that usually starts in the teens, is usually diagnosed in the late twenties, and until now had systemic options licensed only for the second half of that timeline. The approval doesn't invent a treatment. It removes an argument.

Ten years, three doctors, three wrong answers

The diagnostic delay in HS is not an anecdote, and it has been measured carefully. A prospective multicentre study published in Dermatology in 2020 assessed 394 adult HS patients in Germany and found the average interval from first symptoms to diagnosis was ten years, with a standard deviation nearly as large. In that decade patients consulted, on average, more than three different physicians — general practitioners, dermatologists, surgeons, gynaecologists — and collected more than three misdiagnoses along the way.

Two findings from that study matter more than the headline number. First: the delay was longer in younger patients. The people most likely to be at the start of the disease are the people least likely to be believed about it. Second: the longer the delay, the greater the disease severity at diagnosis, and the more surgical treatment that followed.

That second finding is the clinical argument for treating early, and it turns on a structural fact about HS. Inflammatory nodules and abscesses are treatable events. Sinus tracts — tunnels — and the rope-like scarring that follows them are architecture. Once the skin has remodelled itself into a network of epithelialised channels, no injection puts it back; that becomes a surgical problem, permanently. The window in which systemic anti-inflammatory therapy prevents rather than merely suppresses is measured in the years when most patients are being told they have recurrent boils and should shower more often.

What the trials showed, and what was extrapolated

Honest reporting on this approval requires two caveats, and neither is a reason to dismiss it.

The first is effect size. Secukinumab's HS licence rests on SUNSHINE and SUNRISE, two identical phase 3 trials published in The Lancet in 2023 across 219 sites in 40 countries, enrolling roughly 540 patients each. The primary endpoint was a fifty percent reduction in abscess and inflammatory nodule count at week 16 without any increase in abscesses or draining fistulae. In SUNSHINE, the every-two-weeks arm reached that response in about 45% of patients against 34% on placebo; in SUNRISE the figures were about 42% and 46% for the two dosing arms against 31% on placebo. Responses were sustained to week 52 and the safety profile held, with headache the most common adverse event.

Read those percentages properly. This is a real, replicated, statistically significant benefit — and it is roughly one additional responder in every ten patients treated, measured against a placebo arm that also improved. For a disease with very few options that is genuinely worth having. It is not remission, and anyone presenting it as such is selling something.

The second caveat is that no paediatric HS efficacy trial underpins this approval. The extension rests on the adult trials, pharmacokinetic modelling to select weight-based dosing, and paediatric safety experience from secukinumab's other licensed indications in children — plaque psoriasis, enthesitis-related arthritis and psoriatic arthritis. Extrapolation of this kind is a standard and defensible regulatory route when the underlying disease biology is taken to be the same across ages, and it spares adolescents from being enrolled in trials for a condition that already has an adult evidence base. It also means the adolescent-specific efficacy data will accumulate after approval rather than before it. Both things are true.

A third detail deserves more attention than it gets: patients in SUNSHINE and SUNRISE agreed to daily use of over-the-counter topical antiseptics on affected areas throughout the study. The biologic effect was measured on top of that background. ↗Benzoyl peroxide washes are the usual real-world version — something like PanOxyl's 4% creamy wash for skin that finds higher strengths punishing, or the sturdier PanOxyl cleansing bar and Differin's maximum-strength foaming cleanser for the axillae and groin, where they're used as short-contact washes rather than left on. None of this is a treatment for HS. It's the floor the trials were built on, and it is routinely dropped the moment a systemic drug enters the conversation.

Getting a teenager taken seriously in the room

The approval changes what a clinician can offer. It does not change how hard it is to get through the door, and that is where most of this disease's damage is still done.

The single most useful thing anyone can bring to a first appointment is the vocabulary. "Recurrent boils in the armpits and groin, in the same places, that come back" is a description that invites another course of antibiotics. "I think this is hidradenitis suppurativa" is a description that starts a different conversation, and the diagnosis is clinical — recurrent lesions, in characteristic sites, with a characteristic pattern, no test required.

Bring a stage as well as a name. Our HS Severity Check walks through Hurley staging and the IHS4 count, where nodules score one, abscesses two, and draining tunnels four — an arithmetic that makes the difference between mild and severe explicit rather than impressionistic, and that a clinician will recognise immediately. Photographs matter more here than in almost any other skin condition, because HS is defined by recurrence and a flare rarely coincides with an appointment; the Photo Tracker keeps a dated, consistent record so "it comes back every few weeks" has evidence behind it. And the Derm Visit Prep tool exists for exactly the appointment where a teenager needs to be believed the first time, which is the appointment this approval has now made worth winning.

One last thing worth saying, because it comes up in every HS consultation and it is wrong. This is not a hygiene problem, it is not caused by shaving or deodorant, and the immune mechanisms driving it are still only partly understood — a 2025 review of HS pathogenesis describes a mixed innate and adaptive inflammatory response whose dynamics remain poorly characterised, which is why current systemic therapy targets TNF or IL-17 rather than something more precise. Anyone who has been told to wash more thoroughly has been given advice that has nothing to do with the disease, and has usually lost a year to it.