Staging Hidradenitis and Matching the Treatment

How is hidradenitis suppurativa staged?

By what has been left behind, not by how much it hurts. The Hurley system sorts the disease into three stages according to whether tunnels and scarring have formed and how much of an area they occupy. Hidradenitis suppurativa is a chronic inflammatory disease of the hair follicle, producing painful deep nodules, abscesses and draining tunnels in the armpits, groin, buttocks and under the breasts 1Ref 1Sabat R, Jemec GBE, Matusiak Ł, et al. (2020).Hidradenitis suppurativa.Background definition and mechanism: that hidradenitis suppurativa is a chronic inflammatory disease of the hair follicle producing painful deep nodules, abscesses and draining tunnels, and that it recurs characteristically in intertriginous sites such as the armpits, groin, buttocks and under the breasts., and staging is how clinicians decide which tier of treatment the disease has earned.

The North American guideline treats severity assessment as a distinct step from treatment for exactly this reason: what is decided is not merely how bad things are, but which kind of intervention the tissue can still respond to 2Ref 2Alikhan 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.That severity assessment is a distinct step in hidradenitis management and is expressed in Hurley stages defined by the presence of sinus tracts and scarring and the extent of involvement; that procedural management — drainage, deroofing, and wider excision — sits alongside rather than after medical management; and that comorbidity screening is recommended as part of evaluation..

The stage is set by tunnels and scarring — permanent structural change — not by pain, drainage, or how many days this month were ruined.

What the Hurley stage does not tell you

It does not measure how active the disease is right now, and this is the single most useful thing to understand about it. Hurley describes architecture: what has been destroyed and rebuilt as scar. Someone at stage I can be having the worst month of their life, with recurring abscesses that have simply not yet cut permanent tunnels. Someone at stage III can be relatively quiet for a stretch while their scarred tissue sits unchanged.

That gap has a practical cost. Access to systemic treatment is frequently discussed in terms of stage, which can leave a person with severe, frequently recurring stage I disease sounding milder on paper than they are. The counter is not to argue with the staging — it is accurate for what it measures — but to bring the other half of the picture: how many flares in the last six months, how many days of work or school lost, how much of the day is organised around dressings, pain, and hiding drainage.

Stage answers "what has this disease built?" Frequency, pain, and lost days answer "what is it doing to me?" Both belong in the appointment.

There are other severity instruments used in research that count inflammatory lesions rather than scars, and a dermatologist may use one. Hurley remains the shorthand everyone writes down, because it maps most directly onto whether surgery is going to be part of the answer.

Hurley stage 1: before the tunnels form

Stage I is defined by absence — abscesses or nodules with no sinus tracts and no scarring yet 2Ref 2Alikhan 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.That severity assessment is a distinct step in hidradenitis management and is expressed in Hurley stages defined by the presence of sinus tracts and scarring and the extent of involvement; that procedural management — drainage, deroofing, and wider excision — sits alongside rather than after medical management; and that comorbidity screening is recommended as part of evaluation.. It is also the stage where the diagnosis is most often not made at all, because a single painful lump in the armpit or groin looks like an infected hair follicle or a boil to almost everyone who has not seen this disease before.

What separates it from a boil is repetition and location. Hidradenitis recurs, and it recurs in the same intertriginous sites — the places where skin meets skin 1Ref 1Sabat R, Jemec GBE, Matusiak Ł, et al. (2020).Hidradenitis suppurativa.Background definition and mechanism: that hidradenitis suppurativa is a chronic inflammatory disease of the hair follicle producing painful deep nodules, abscesses and draining tunnels, and that it recurs characteristically in intertriginous sites such as the armpits, groin, buttocks and under the breasts.. A second lump in the same armpit is worth naming as a pattern rather than describing as a fresh problem, because the pattern is the diagnostic clue.

What early treatment is trying to buy. Not just relief from the current lesion. The tunnels that define stage II are built out of repeated inflammation in the same tissue, so the argument for treating early and treating properly is that scarred architecture, once formed, does not respond to anti-inflammatory drugs. Early hidradenitis and what still works is a genuinely different conversation from late disease.

Measures at this stage include topical treatment, attention to the local skin environment — friction, heat, and moisture in the folds all matter — and drainage or removal of individual lesions where a specific abscess needs it 2Ref 2Alikhan 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.That severity assessment is a distinct step in hidradenitis management and is expressed in Hurley stages defined by the presence of sinus tracts and scarring and the extent of involvement; that procedural management — drainage, deroofing, and wider excision — sits alongside rather than after medical management; and that comorbidity screening is recommended as part of evaluation.. Systemic medication is not reserved for later stages by rule; recurrent stage I disease is a common reason to start it.

Hurley stage 2: where most people actually are

Stage II means tracts and scarring exist, but the affected lesions are still separated from one another rather than merged into one continuous area 2Ref 2Alikhan 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.That severity assessment is a distinct step in hidradenitis management and is expressed in Hurley stages defined by the presence of sinus tracts and scarring and the extent of involvement; that procedural management — drainage, deroofing, and wider excision — sits alongside rather than after medical management; and that comorbidity screening is recommended as part of evaluation.. This is the stage at which most people are finally diagnosed, and it is where medical and procedural treatment stop being alternatives and start running in parallel.

The reason is mechanical. A sinus tract is an epithelialised channel under the skin — the body has lined the tunnel — and a drug that reduces inflammation does not close a lined tunnel. So the working division is that medical therapy is aimed at reducing new lesions and calming inflammation, while a targeted procedure addresses the specific tunnels that keep filling and draining regardless of what is being taken.

A sinus tract, or tunnel, is a channel that has formed under the skin between lesions and has become lined with skin cells, which is why it persists rather than healing shut.

Systemic options at this stage span several classes with different rationales. Hormonal hs treatment is one of them and is often raised when flares track the menstrual cycle. Oral antibiotics are commonly used, in part for reasons that have little to do with killing bacteria. And this is the stage at which the biologic conversation properly begins.

The practical marker that stage II care is not working is not a bad week. It is a tunnel that has drained continuously for months, or new tracts appearing while on treatment — either of which is a reason to bring surgery into the plan rather than to wait for stage III.

Hurley stage 3: when the disease becomes one piece

Stage III is diffuse involvement, or multiple interconnected tracts and abscesses across an entire area 2Ref 2Alikhan 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.That severity assessment is a distinct step in hidradenitis management and is expressed in Hurley stages defined by the presence of sinus tracts and scarring and the extent of involvement; that procedural management — drainage, deroofing, and wider excision — sits alongside rather than after medical management; and that comorbidity screening is recommended as part of evaluation.. The distinction from stage II is not severity of pain but continuity: an armpit or a groin behaving as a single diseased field rather than as separate lesions in the same neighbourhood.

At this stage the two halves of treatment are both essential and neither is sufficient. Systemic and biologic therapy reduces inflammatory activity in the tissue and in whatever disease is developing elsewhere on the body. Wider surgical management addresses tissue that has already been structurally lost 2Ref 2Alikhan 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.That severity assessment is a distinct step in hidradenitis management and is expressed in Hurley stages defined by the presence of sinus tracts and scarring and the extent of involvement; that procedural management — drainage, deroofing, and wider excision — sits alongside rather than after medical management; and that comorbidity screening is recommended as part of evaluation.. Doing only the first leaves scarred tunnels that will keep draining; doing only the second leaves the disease free to build new tunnels at the edges of the repair.

Mobility becomes part of the assessment. Scarring across a fold contracts. When it does, the limitation is no longer only pain — an arm that cannot be raised fully, or thighs that cannot be separated comfortably, is a functional problem that changes what surgery is for and how urgently it is discussed.

Stage III is also where the accumulated costs of the disease get counted properly: chronic pain, the wound care that structures a day, the smell and drainage that people organise their lives around, and the isolation that follows. None of that is a soft consideration bolted onto the medical facts. It is part of what a treatment plan at this stage is being asked to change.

What the biologic evidence actually shows

The evidence base here is much smaller than in psoriasis or eczema, and one trial programme carries most of it. PIONEER I and PIONEER II were phase 3 randomised placebo-controlled trials of adalimumab, a tumour necrosis factor inhibitor, in moderate-to-severe hidradenitis suppurativa. Adalimumab significantly increased clinical response at week 12 compared with placebo, and those trials were the basis for the first biologic indication in this disease 3Ref 3Kimball AB, Okun MM, Williams DA, et al. (2016).Two Phase 3 Trials of Adalimumab for Hidradenitis Suppurativa.That the PIONEER I and PIONEER II phase 3 randomised placebo-controlled trials showed adalimumab, a tumour necrosis factor inhibitor, significantly increased clinical response at week 12 in moderate-to-severe hidradenitis suppurativa, and that these trials were the basis for the first biologic indication in this disease. Also cited for the bounds of that evidence: placebo comparison, moderate-to-severe disease, week 12..

Read as carefully as it deserves, that is a real result and a bounded one. The comparison was against placebo in moderate-to-severe disease, and the primary read was at week 12 3Ref 3Kimball AB, Okun MM, Williams DA, et al. (2016).Two Phase 3 Trials of Adalimumab for Hidradenitis Suppurativa.That the PIONEER I and PIONEER II phase 3 randomised placebo-controlled trials showed adalimumab, a tumour necrosis factor inhibitor, significantly increased clinical response at week 12 in moderate-to-severe hidradenitis suppurativa, and that these trials were the basis for the first biologic indication in this disease. Also cited for the bounds of that evidence: placebo comparison, moderate-to-severe disease, week 12.. It establishes that blocking a specific inflammatory pathway changes the course of this disease, which was not previously proven — an important thing to know if you have been told hidradenitis is a hygiene problem or a weight problem.

The existence of a placebo-controlled trial result here matters. It is proof that this is an immune disease with a drug target, not a failure of washing.

What it does not settle is how one biologic compares with another, what happens beyond the trial window, or who responds best. Newer agents targeting other inflammatory pathways have since been developed for this disease, and the field is moving faster than it has in decades — which is a reason to ask a dermatologist what is currently available rather than to rely on any page, including this one, for the current list.

Where surgery sits in the sequence

Not at the end. Procedural management sits alongside medical management in the North American guideline rather than after it 2Ref 2Alikhan 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.That severity assessment is a distinct step in hidradenitis management and is expressed in Hurley stages defined by the presence of sinus tracts and scarring and the extent of involvement; that procedural management — drainage, deroofing, and wider excision — sits alongside rather than after medical management; and that comorbidity screening is recommended as part of evaluation., and treating hs surgery as a last resort is one of the more damaging misconceptions in this disease, because it means people spend years cycling through drugs while a specific tunnel keeps draining.

The procedures answer different questions. Incision and drainage relieves the pressure of an acute abscess — it is pain relief for a specific lesion, and the tunnel underneath is unaffected by it, which is why lesions treated this way so often come back in the same place. Deroofing removes the roof of a tract and lets the base heal open, dealing with the tunnel itself while removing far less tissue than an excision. Wide excision removes a whole diseased field and is what stage III disease in a single region is sometimes reduced to.

Draining an abscess treats today. Removing or deroofing the tunnel treats the structure that makes tomorrow's abscess.

The sequencing question worth asking directly is whether a dermatologist and a surgeon are talking to each other. Medical therapy before and after a procedure is what protects the surrounding skin from building the next tract, and the best outcomes in this disease generally come from the two halves being planned together rather than referred sequentially by a person who has run out of options.

It is not acne, and the delay costs years

Almost everyone with this disease has been treated for something else first — a boil, a cyst, an infection, or acne. The confusion has a basis: hidradenitis is a follicular disease, it was once called acne inversa, and the drugs offered early often come from the acne shelf. But the guidelines are separate documents with separate reasoning, and being handed the wrong one is a sign the diagnosis has not been made 2Ref 2Alikhan 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.That severity assessment is a distinct step in hidradenitis management and is expressed in Hurley stages defined by the presence of sinus tracts and scarring and the extent of involvement; that procedural management — drainage, deroofing, and wider excision — sits alongside rather than after medical management; and that comorbidity screening is recommended as part of evaluation..

The acne guideline recommends benzoyl peroxide, topical retinoids, topical antibiotics, and oral doxycycline, with oral isotretinoin strongly recommended for severe, scarring, psychosocially burdensome, or refractory acne 4Ref 4Reynolds RV, Yeung H, Cheng CE, et al. (2024).Guidelines of care for the management of acne vulgaris.That the AAD acne guideline strongly recommends benzoyl peroxide, topical retinoids, topical antibiotics and oral doxycycline, and strongly recommends oral isotretinoin for severe, scarring, psychosocially burdensome or refractory acne — cited here to show that acne has its own separate guideline and that being managed from it is a sign hidradenitis has not been diagnosed.. That is a coherent plan for acne. The oral tetracyclines that many people with hidradenitis have already taken are best characterised in that same acne literature, where a systematic review supports their efficacy for inflammatory lesions and argues for limiting duration and preferring narrower-spectrum agents 5Ref 5Armstrong AW, Hekmatjah J, Kircik LH (2020).Oral Tetracyclines and Acne: A Systematic Review for Dermatologists.That the oral tetracycline class is characterised in the acne literature by a systematic review supporting efficacy for inflammatory acne lesions and an antibiotic-stewardship rationale for limiting duration and preferring narrower-spectrum agents — cited here as the evidence base these drugs come from..

What to say to move the conversation. Three features distinguish this disease from acne in a sentence: the sites are the folds rather than the face, chest and back; the lesions are deep and painful rather than surface comedones; and tunnels form. Naming those three is often what turns a repeat visit into a referral.

Hidradenitis also travels with other conditions, and the guideline recommends screening for them rather than waiting for symptoms 2Ref 2Alikhan 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.That severity assessment is a distinct step in hidradenitis management and is expressed in Hurley stages defined by the presence of sinus tracts and scarring and the extent of involvement; that procedural management — drainage, deroofing, and wider excision — sits alongside rather than after medical management; and that comorbidity screening is recommended as part of evaluation.. That is why a thorough first dermatology visit for this disease may ask about inflammatory bowel symptoms, joint pain, metabolic health, smoking, and mood — none of which are a change of subject.