Hidradenitis Suppurativa: Why Painful Lumps in the Armpits, Groin, and Under the Breasts Keep Coming Back, Why It Is Not an Infection or a Hygiene Problem, Where Antibiotics, Biologics, Laser, and Surgery Fit, and What It Means for Anyone Planning Cosmetic Surgery

The story usually starts in the late teens or early twenties. A tender lump appears in one armpit, swells over a few days, and either fades or bursts and drains. A walk-in clinic calls it a boil and prescribes an antibiotic. A few months later there is another one, then two in the groin, then one in the fold under a breast. Someone suggests a stronger deodorant, an antibacterial wash, or shaving less. Someone else lances one, which helps for a week. By the time the pattern has a name, the skin in those places may be crossed by tunnels that drain on and off and by rope-like scars that pull when the arm is raised.

That name is hidradenitis suppurativa, often shortened to HS. Patient surveys and clinical studies have repeatedly found that people with it wait, on average, around seven years or more between the first lump and the diagnosis. The delay matters, because the disease is far easier to control before tunnels and scarring set in, and because many of the things done to it in the meantime (repeated lancing, aggressive scrubbing, and courses of antibiotics that are stopped as soon as one lump settles) do little to change its course.

This piece explains what HS is and who gets it, how its severity is judged, what medical treatment does and does not accomplish, where laser hair removal and surgery fit, and what the condition means for anyone planning cosmetic surgery in the armpit, chest, abdomen, or groin. It is general information, not a diagnosis. A lump that is hot, spreading, accompanied by fever, or rapidly enlarging needs to be seen promptly, and any long-standing open wound in an area of HS that changes character deserves a biopsy.

What hidradenitis suppurativa actually is, and who gets it

The short answer: hidradenitis suppurativa is a chronic, recurring inflammatory disease that begins with a blocked hair follicle in skin where body surfaces rub together, not an infection of the sweat glands and not a result of poor hygiene, and it most often starts after puberty in people who are female, overweight, or smokers, or who have a family history of it.

The old name is misleading. "Hidradenitis" means inflammation of sweat glands, and for a long time the disease was blamed on the apocrine glands of the armpit and groin. Modern pathology places the first event in the hair follicle instead: the follicle becomes plugged, dilates, and ruptures under the skin, spilling its contents into the surrounding tissue. The immune system responds the way it would to a foreign body, with an intense inflammatory reaction driven in large part by signaling molecules such as tumor necrosis factor and interleukin-17. That is why the disease is now grouped with conditions like psoriasis and Crohn's disease, and why the drugs that changed its treatment are the same kind used for those diseases.

Bacteria are present in HS lesions, and secondary infection does happen, but the lumps are not fundamentally an infection. That distinction explains a great deal of patient frustration. A boil caused by staph bacteria usually resolves with drainage and, when needed, an antibiotic. An HS nodule may improve on an antibiotic, partly because some antibiotics also dampen inflammation, and then return in the same spot or nearby once the course ends.

The pattern of where it appears is close to diagnostic. Dermatology guidelines, including the North American clinical management guidelines from the United States and Canadian Hidradenitis Suppurativa Foundations published in the Journal of the American Academy of Dermatology, describe the diagnosis as clinical, based on three features:

• Typical lesions. Deep, painful nodules, abscesses, draining tunnels (also called sinus tracts), and characteristic scarring, sometimes with paired blackheads.
• Typical locations. The armpits, the groin and inner thighs, the area under and between the breasts, the buttocks and the skin around the anus, and less often the nape of the neck or behind the ears.
• Recurrence. Lesions that keep returning over months, rather than a single episode.

Estimates of how common HS is vary widely depending on how it is counted, from a fraction of one percent in studies of diagnosed patients to around one percent in some population surveys, which almost certainly reflects how often it goes unrecognized. In the United States and Europe, women are affected roughly two to three times as often as men. Smoking and obesity are the two strongest modifiable associations, and roughly a third of patients report a relative with the condition. HS also travels with other conditions, including inflammatory bowel disease, inflammatory arthritis, metabolic syndrome, polycystic ovary syndrome, and depression, a cluster discussed in the broader piece on cosmetic surgery with autoimmune disease.

The look-alikes are worth knowing, because several of them have been covered here before. A single, mobile lump in the armpit may be accessory breast tissue or a cyst; small bumps around hairs after shaving are more likely razor bumps and ingrown hairs; a single closed sac with a pore is usually an epidermoid cyst of the kind described in the piece on cyst and lipoma removal. Draining tracts near the anus can come from Crohn's disease or a fistula, and a cleft above the buttocks with recurrent abscesses suggests pilonidal disease. The difference with HS is the combination: multiple deep lesions, in multiple fold areas, coming back again and again.

How severity is judged, and why the stage decides everything

The short answer: HS is staged by whether tunnels and scarring have formed and how widespread they are, most often with the three-level Hurley system, and the stage is the single most important factor in choosing between medication alone, a minor procedure, or a larger excision.

The Hurley staging system, first described in 1989, is old and blunt, but it is still the shared language between dermatologists and surgeons:

• Hurley stage I. One or more abscesses or nodules, without tunnels and without scarring.
• Hurley stage II. Recurrent abscesses with tunnels and scarring, as single or multiple lesions separated by normal-looking skin.
• Hurley stage III. Diffuse or near-diffuse involvement, with multiple interconnected tunnels and abscesses across an entire area.

Most patients are stage I or II. Stage III is less common but accounts for a large share of the pain, disability, and surgery. Newer scoring tools, such as the International Hidradenitis Suppurativa Severity Score System (IHS4), count nodules, abscesses, and draining tunnels to give a number that can be tracked over time, and clinical trials use measures such as HiSCR, which asks whether the count of inflammatory lesions has dropped by at least half without new abscesses or tunnels appearing.

Two features of staging matter to a patient. First, stage is judged area by area. A person can have stage III disease in one armpit and stage I in the groin, and the plan for each region can differ. Second, tunnels and scars do not go away on medication. Drugs can calm inflammation, reduce flares, and stop new tunnels from forming, but an established tunnel is a physical structure lined with skin-like tissue, and it tends to keep draining until it is opened or removed. That is the logic behind combining medical and surgical treatment, rather than treating them as rival options.

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Hidradenitis is not a hygiene problem and not a series of unlucky boils. It is a chronic inflammatory disease that builds tunnels under the skin, and the tunnels do not read the prescription.

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Staging also explains why the condition is so frequently undertreated. A patient whose lumps are called boils is treated one lump at a time, and nobody counts the regions involved, maps the tunnels, or notices that the disease has advanced from stage I to stage II over three years. A dermatologist who sees HS regularly will usually examine every fold area, not just the one that hurts that week, and will ask about pain, drainage, odor, and the effect on work and relationships, all of which are part of judging severity.

Pain deserves its own mention. HS can be among the most painful conditions in dermatology, and patients frequently report that the pain, the drainage through clothing, and the smell matter more to them than the appearance of the scars. The guidelines treat pain control as part of management, not an afterthought.

What medical treatment does: antibiotics, hormones, steroids, and biologics

The short answer: medical treatment for HS is layered by severity, starting with topical and oral antibiotics used mainly for their anti-inflammatory effect, adding hormonal options for some women and steroid injections for single painful nodules, and moving to biologic drugs, three of which are now FDA approved, for moderate to severe disease.

Topical and oral antibiotics. For mild disease, topical clindamycin is a common starting point, often alongside an antiseptic wash such as chlorhexidine or benzoyl peroxide. For more widespread or recurrent stage I and II disease, oral tetracyclines such as doxycycline are commonly prescribed for several months. For more active disease, the combination of clindamycin and rifampin taken together for around ten to twelve weeks is a well-studied option. These drugs help many patients, but the effect often fades after they stop, and long courses carry the usual concerns about resistance and side effects. The general principles of when antibiotics help and when they only add risk are covered in the piece on antibiotics after cosmetic surgery.

Hormonal and metabolic options. Many women notice flares around their periods, and HS often begins after puberty, which has led to the use of anti-androgen treatments such as spironolactone and certain combined oral contraceptives. Metformin, the diabetes drug, has some supporting evidence, particularly in patients with insulin resistance. The evidence for these is weaker than for biologics, but they are inexpensive, widely available, and reasonable adjuncts.

Steroid injections. A single acutely painful nodule can often be calmed within a day or two with an injection of a dilute corticosteroid, typically triamcinolone, directly into the lesion. It is a rescue measure for flares, not a long-term plan.

Biologics. This is where the treatment of HS changed. Adalimumab, which blocks tumor necrosis factor, was approved by the FDA for moderate to severe HS in 2015, based on the PIONEER trials, and later extended to adolescents. Secukinumab, which blocks interleukin-17A, was approved for HS in 2023, and bimekizumab, which blocks interleukin-17A and 17F, followed in 2024. In the pivotal trials, a substantially larger share of patients on the drug than on placebo reached a meaningful reduction in inflammatory lesions, though a sizable minority did not respond well to any single agent. Infliximab and several other drugs are used off-label by specialists. These are injected medications that suppress part of the immune system, require screening for tuberculosis and other infections before starting, and are expensive enough that insurance approval can take time.

Weight loss and smoking. Both matter. Observational studies link higher body weight and smoking with more severe disease, and many patients report improvement after substantial weight loss or quitting smoking. Neither is a cure, and both are hard, but they change the baseline the other treatments work against. GLP-1 drugs such as semaglutide are increasingly being studied in HS, partly for their weight effect and possibly for direct anti-inflammatory effects, but that research is early. The surgical considerations for patients on those drugs are covered in the piece on GLP-1 drugs before plastic surgery.

What medical treatment cannot do is erase established tunnels and thick scar. A biologic may reduce the number of flares and new abscesses dramatically while a chronic tunnel in the armpit keeps draining a little every day. That remaining structural disease is what surgery addresses.

Laser, deroofing, and excision: why lancing rarely ends the problem

The short answer: simple incision and drainage relieves pain from a tense abscess but leaves the diseased tunnel behind, so lesions usually return, while deroofing opens and clears the tunnel and wide excision removes the diseased skin entirely, with lower recurrence; laser hair reduction can help in early disease by targeting the follicle where HS begins.

Incision and drainage. Lancing an abscess releases pus and pressure, and in an acute, exquisitely painful lesion it can be the right call for comfort. The problem is that it treats the symptom. The tunnel and the inflamed follicles around it remain, and studies of patients treated with drainage alone report that the large majority experience recurrence. Repeated lancing of the same area is a sign that the plan needs to change, not that the next drainage will be the one that works.

Deroofing. For recurrent nodules and tunnels in stage I and II disease, deroofing has become a standard office procedure. Under local anesthesia, the surgeon or dermatologist probes the tunnel, removes its roof (the skin and tissue above it), and scrapes out the gelatinous material inside, leaving the floor of the tunnel open to heal from the bottom up over a few weeks. The wound looks larger than patients expect, but it heals with a flatter scar, and published series report that most treated lesions do not return in the same spot.

Wide local excision. For stage II disease with clustered tunnels and for stage III disease, surgeons remove all of the visibly involved skin in a region, with a margin of normal-appearing tissue. The resulting wound can be left to heal on its own (secondary intention), closed with a skin graft, or reconstructed with a local flap, such as a perforator flap from the side of the chest for an armpit. Each choice trades healing time against scar quality and arm mobility. Healing by secondary intention can take many weeks but often gives a surprisingly supple result in the armpit; grafts and flaps shorten healing but add donor sites and, with grafts, a risk of contraction. Recurrence after wide excision is lower than after limited or local excision in most reports, and generally lower in the armpit than in the groin and the area around the anus, where disease tends to be more extensive. Carbon dioxide laser excision and vaporization are used by some centers as alternatives.

Surgery and biologics together. A long-standing worry was that operating on patients taking a biologic would raise the risk of infection. A randomized trial published in JAMA Surgery in 2021 (the SHARPS study) gave adalimumab to patients undergoing HS surgery, continued it through the operation, and found no increase in postoperative infections or complications, with better disease control than placebo. Guidelines increasingly favor medical control first, surgery for the structural disease that remains, and continued medical treatment afterward to reduce new lesions elsewhere.

Laser hair reduction. Because HS begins in the hair follicle, reducing hair in the affected areas is a logical target. Small randomized trials of the long-pulsed Nd:YAG laser have shown improvement in early disease, and the North American guidelines list it as an option for stage II and selected stage I patients. It is not a substitute for medical treatment in active, advanced disease, and it should be done by an experienced practice that knows it is treating HS rather than routine hair removal. The broader limits of the technology are covered in the piece on laser hair removal, and the question of who should be operating the machine in the piece on med spa supervision.

What does not have good evidence. Treatments aimed at sweat glands, such as microwave sweat-gland destruction, are designed for excessive sweating, not HS, and are not established HS treatments. Botulinum toxin, discussed in the piece on Botox for hyperhidrosis, has been studied in HS only in small trials and is not standard care. Antibacterial soaps and harsh scrubs do not prevent new lesions and can irritate skin that is already inflamed.

One more point on long-standing disease. In rare cases, chronic HS, particularly of the buttocks and perineum in men who smoke and have had the disease for decades, can develop squamous cell carcinoma within the scarred tissue. It is uncommon, but it is the reason any area that changes character (a new ulcer, a firm growth, bleeding that will not stop) should be biopsied rather than assumed to be another flare.

What HS means for cosmetic surgery in the armpit, chest, abdomen, and groin

The short answer: HS does not rule out cosmetic surgery, but it changes where incisions should go, when the operation should happen, and who should be involved, and in a few situations a body-contouring operation can remove diseased skin and help the condition rather than worsen it.

The first question is whether the incision will pass through, or near, skin that is affected or prone to flares. Several common operations put scars in exactly the territory HS favors:

• Breast augmentation through the armpit. The transaxillary approach, compared with the fold and areola incisions in the piece on augmentation incision choice, places a scar and a dissection tunnel in the armpit. In a patient with axillary HS, most surgeons will steer toward a different incision.
• Breast reduction and lift. The inframammary fold, where the horizontal scar of an anchor-pattern breast reduction sits, is a classic HS site. Small published series suggest that in some women with HS under the breasts, reduction surgery that removes heavy, overhanging tissue and part of the involved fold skin is followed by improvement, but this is not a guaranteed effect, and active disease in the fold raises the risk of wound separation along that scar.
• Tummy tuck, panniculectomy, and monsplasty. The lower abdominal fold and the pubic area are common HS sites, especially after major weight loss. An operation such as a panniculectomy or tummy tuck, or a monsplasty, can sometimes remove involved skin and eliminate the fold that keeps it moist and rubbing. That is a reconstructive goal as much as a cosmetic one, and it should be planned with that in mind.
• Thigh lift, arm lift, and body lift. The inner thigh and groin incisions of a thigh lift, the armpit end of an arm lift, and the circumferential scar of a lower body lift all run through HS territory. Patients should mention any history of lumps or drainage in those areas, even if it has been quiet for years.

The second question is timing. Most surgeons prefer to operate when the disease is quiet, after a period of medical control, rather than in the middle of a flare. The SHARPS trial suggests that adalimumab need not be stopped for HS surgery itself, and many surgeons apply similar reasoning to cosmetic surgery, but decisions about pausing any immune-suppressing drug around an elective operation should be made jointly by the surgeon and the prescribing dermatologist, not by the patient alone. The same logic, and the same conversations, are covered for other immune-modifying drugs in the piece on autoimmune disease linked above, and for corticosteroids in the piece on steroids for swelling.

The third question is the shared risk factors. HS travels with smoking, higher body weight, and insulin resistance, and each of those independently raises the risk of wound problems after any operation. The relevant pieces are on smoking cessation timelines, BMI limits for cosmetic surgery, and blood sugar before surgery. A patient with HS who still smokes is not just carrying the risk of the disease; they are stacking it on top of the single strongest modifiable predictor of wound healing trouble.

Finally, compression garments, surgical tape, and drains all sit against fold skin for weeks after body contouring. For someone with HS, friction and trapped moisture are known triggers, so garment fit, padding, and skin care deserve explicit attention in the recovery plan. Scars in HS-prone areas also tend to be watched more closely, and the general principles in the piece on scar care apply with extra emphasis on keeping the skin dry and unirritated. A consultation that does not ask about HS when the planned incision runs through the armpit or groin is a reasonable moment to seek a second consultation.

The honest summary

Hidradenitis suppurativa is a chronic inflammatory disease that starts in blocked hair follicles in fold skin and produces deep, painful lumps, draining tunnels, and scars in the armpits, groin, under the breasts, and around the buttocks. It is not caused by poor hygiene and it is not simply a run of boils, which is why the usual answers, an antibiotic for each lump, a stronger soap, another lancing, so often fail. Too many patients wait years for the correct name, and the disease is easier to control before tunnels form.

Treatment follows the stage. Mild disease is managed with topical treatment, antiseptic washes, and sometimes months of oral antibiotics used for their anti-inflammatory effect, with hormonal options and steroid injections as adjuncts. Moderate to severe disease now has three FDA-approved biologics, adalimumab, secukinumab, and bimekizumab, which reduce flares in many but not all patients. Laser hair reduction can help in early disease. Established tunnels and scarred skin do not dissolve on medication; deroofing removes individual tunnels with a low local recurrence rate, and wide excision removes involved regions, ideally with medical treatment continued around it.

For anyone planning cosmetic surgery, HS is a planning issue, not an automatic disqualification. It should steer incisions away from active disease, push the operation into a quiet period, bring the dermatologist into decisions about immune-suppressing drugs, and sharpen attention to smoking, weight, blood sugar, and friction under garments. In the right patient, a reduction, a panniculectomy, or a monsplasty can even remove involved skin and the fold that feeds it. The essential step is telling the surgeon about it, plainly and early, rather than hoping the armpit or groin stays quiet through recovery.