Condition

Hidradenitis Suppurativa

Hidradenitis suppurativa is a long-term inflammatory condition that causes painful lumps, abscesses and tunnels in the armpits, groin and under the breasts. It is not an infection and it is not caused by poor hygiene, and treating it early is what prevents the scarring.
Dr. Schwarz, MD · Board-certified dermatologistLast reviewed September 8, 2026
16:9 hero for Hidradenitis Suppurativa. Never cropped: the tone strip and the corner logo depend on the full frame.

Start here

Most people who reach me with hidradenitis suppurativa have been told for years that they get boils — cut and drained, course after course of antibiotics, and more than one question about how they wash. This has nothing to do with hygiene. The delay is the real problem, because it commonly takes years to get the name and those are the years the tunnels and scars that are hardest to treat are forming, so if a painful lump has come back in the same fold more than twice, get a proper appointment. It is treatable — not curable, but treatable — and the options run well past antibiotics to hormonal treatment, biologic injections and small procedures that permanently remove a tunnel.

— Dr. Schwarz, Board Certified Dermatologist

Key Facts

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How commonAround one in a hundred people, though it is heavily under-diagnosed and often goes years without a name
Who gets itUsually starts after puberty, most often between the late teens and the thirties. More common in women, and in people with a family history
Curable or managedManaged. Early disease can be controlled well with medication; established tunnels and scars need a procedure to remove
Prescription neededYes, for anything beyond an antiseptic wash
Time to improveWeeks to a few months for most medications. A single flare settles over days

What It Is

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Hidradenitis suppurativa is an inflammatory condition of the hair follicle, not the sweat glands, despite the name. It affects skin that folds and rubs — the armpits, groin, buttocks, inner thighs, and under the breasts. It is sometimes called acne inversa, because it behaves like severe acne in the wrong places.

It takes a few forms, usually in the same person over time. Deep painful lumps that feel like a marble under the skin and last days to weeks. Abscesses that swell, burst and drain fluid with a strong smell. Blackheads appearing in pairs, side by side, which is specific to this condition. And, over years, sinus tracts — tunnels running under the skin between lumps, draining on and off and never closing.

Doctors stage it with Hurley stages. Stage one is lumps and abscesses with no tunnels. Stage two is tunnels and scarring in separate patches with normal skin between. Stage three is widespread tunnels across a whole area. Staging sets the treatment — stages one and two are largely medical, stage three usually needs surgery as well.

What it is not matters as much. Not contagious, not a sexually transmitted infection, not a hygiene problem, and not primarily bacterial — swabs are often negative or grow ordinary skin bacteria. The pus is the immune system responding to a follicle that burst under the skin, not proof of an infection antibiotics will cure.

Symptoms

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Painful lumps that come and go

Early Nodules

Deep, tender lumps in the armpits, groin, under the breasts or between the buttocks, that swell for days and then settle. They are often mistaken for boils or ingrown hairs for years. Repeat lumps in the same folds are the pattern that matters.
Lumps that burst and leak

Abscesses and Draining

Lumps that enlarge, open and drain pus or blood, sometimes with a strong smell, then refill weeks later. Cutting them open gives short-lived relief without changing the course. This stage is a reason to be seen by a dermatologist.
Ropes and tracts under the skin

Tunnels and Scarring

Long-standing disease joins lumps with tunnels under the skin and leaves rope-like scarring across the area. Movement can become painful and clothing rubs. Treatment at this stage usually combines medication with surgery.

How It Looks by Skin Tone

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An inflamed lump in the armpit on fair skin. The skin over it is swollen, shiny and red, with a pair of small blackhead-like openings in the skin beside it.An inflamed lump in the armpit on medium olive skin. The skin over it is swollen and shiny and reads dull pink-brown, with a pair of small blackhead-like openings beside it.An inflamed lump in the armpit on brown skin. The skin over it is swollen and shiny and reads brown and violet rather than red, with a pair of small blackhead-like openings beside it.An inflamed lump in the armpit on deep brown skin. The skin over it is swollen and shiny and reads dark brown and violet, with flat dark marks and one thick raised scar from older lumps beside it.
LightMediumBrownDeep

Hidradenitis suppurativa is more common in Black patients in the data we have, and it is diagnosed later in that same group.

Part of the delay is what inflammation looks like. The angry red of a flare reads as brown, purple or simply darker on deeper skin tones, so a genuinely inflamed lump gets judged mild and sent away with a wash. Pain, swelling and recurrence in the same fold are the reliable signals and should outweigh color. What is left behind differs too. On deeper skin tones healed lesions leave flat dark marks that take many months to fade, and the raised scars this condition produces are more likely to turn thick or keloid. Both argue for treating sooner and choosing procedures carefully — deroofing a tunnel, which removes its roof rather than cutting out a wide block of skin, generally leaves a better result. Laser hair removal can reduce flares by taking the follicle out of the picture, but the wrong laser on deeper skin tones causes burns and pigment change. The long-pulsed Nd:YAG laser is usually the choice. Ask which device will be used and what experience the clinic has with your skin tone.

Where It Shows Up

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Front view of a whole body with red marks in both armpits, under both breasts, across the groin and on both inner thighs.
Armpits, groin and under the breasts
It affects skin that folds and rubs, where hair follicles sit close together. The armpits and the groin are the most common places, then the inner thighs and under the breasts. It is often on both sides of the body at once.
Back view of a whole body with red marks on both buttocks and in the crease between them. The rest of the body is clear.
Buttocks and the crease between them
The buttocks and the crease between them are the other common site, and the hardest to talk about, which is part of why this condition is diagnosed late. It rarely appears on the face, the back or the lower legs, which is one clue that it is something else.

What Happens in the Skin

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This is what is going wrong under the skin, in the order it happens. Click a step to see it.

How Hidradenitis Suppurativa happens
Skin basics
BARRIEREPIDERMISDERMISPOREOILGLAND0A NORMAL FOLLICLE IN A FOLD1THE FOLLICLE PLUGS2IT BURSTS UNDER THE SKIN3THE IMMUNE SYSTEM REACTS4TUNNELS AND SCARS FORM

In the armpits, groin and under the breasts, hair follicles sit in warm skin that folds and rubs. When one is working normally, the keratin its lining sheds travels up and out through the open pore, and the oil and skin bacteria go with it. Everything ends up above the surface.

A hair follicle in a fold fills with keratin, the protein that makes up the outer layer of skin, and the opening blocks. This is why friction, shaving and heat set flares off, and why the condition sits in folds rather than anywhere else.

The blocked follicle keeps filling from below, swells, and gives way sideways into the deeper tissue instead of opening at the surface. That is the moment a lump becomes painful, and it is why squeezing it makes things worse rather than better.

Keratin, oil and ordinary skin bacteria are now deep in tissue where they do not belong, and the immune system reacts hard. That reaction is the pain, the swelling and the pus, and it is why anti-inflammatory treatment works better here than antibiotics used to kill an infection.

When the same area goes through this cycle again and again, the body walls it off with tunnels lined by skin cells, and thick rope-like scars form around them. Tunnels do not close on their own and medication cannot shut them. Almost everything on the lists below is pushing on this step.

The outer film of dead cells and oil. It holds water in and keeps irritants out, and it is thinner than a sheet of paper. Almost every dry, itchy, stinging skin problem starts here.

The outer layer, and the only one anything in a jar reaches. It renews itself constantly: a cell made at the bottom takes about a month to reach the surface and flake off. Most of what a skincare product does, it does here.

The living layer underneath, holding the blood vessels, the nerves and the collagen. It is where lasting change happens and it is hard to reach: most of what is sold for the skin never gets this far.

The lumps form in four steps.

A hair follicle in a fold plugs with keratin, the protein in the outer layer of skin. It keeps filling from below, swells, and bursts sideways under the skin instead of out through the surface. The immune system meets that spilled material — keratin, oil, bacteria that normally live harmlessly on skin — deep in tissue where it does not belong, and reacts hard. That reaction is the pain, the swelling and the pus. When the same area cycles through this over and over, the body walls it off with tunnels lined by skin cells, and those tunnels do not close.

Why it happens to some people is only partly understood. Genetics matter, and a substantial share of patients have a relative with it. So do hormones, since it starts after puberty, often flares before periods, and frequently settles after menopause. Smoking and excess weight make it considerably worse, though plenty of people with the condition have neither. The underlying problem is an overactive immune response in the skin, which is why medicines that damp that response down work better than antibiotics used as antibiotics.

Risk Factors

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None of these cause hidradenitis suppurativa on their own, and having all of them does not mean you will get it. They raise the odds or worsen an existing case.

Inherited
Family history
Roughly a third have a close relative affected. The strongest single factor, and nothing you can influence.
Inherited
Down syndrome
Linked to earlier onset and more severe disease.
Smoking & friction
Smoking
The most consistent modifiable factor. Smokers have more severe disease and respond less well, and stopping changes the course, not just the flare.
Smoking & friction
Friction
Tight clothing, waistbands, seams and skin rubbing on skin irritate the follicles and commonly set off a flare.
Hormones
Hormones
It starts after puberty, commonly flares the week before a period, and often improves after menopause.
Hormones
Polycystic ovary syndrome
Turns up alongside it more often than chance, usually with irregular periods or unwanted hair growth.
Other health conditions
Excess weight
More folds mean more friction and more affected sites, and body fat adds to inflammation. Weight loss reduces severity.
Other health conditions
Metabolic syndrome
High blood pressure, high blood sugar and abnormal cholesterol are more common here, so have them checked.
Other health conditions
Inflammatory bowel disease
Crohn's disease in particular shares features and treatments with it. Mention new bowel symptoms.

Course

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It runs in flares and quiet periods, and follows a longer arc over years. Not everyone progresses. The toll is real — pain, drainage, dressings, clothes chosen around it, embarrassment about the smell — and rates of depression and anxiety are high, worth raising at an appointment.

First lumpLate teens or twenties
It is usually called a boil

A single painful lump appears in one armpit or the groin. It is drained or given antibiotics, and settles.

ArmpitGroin
It comes backMonths later
The same fold, over and over

The lump returns in the same place. That repeat is the condition announcing itself, and where it should be named. In practice it takes years and several doctors.

Flares and quiet periodsThe ongoing rhythm
A flare settles over one to two weeks

A flare builds over a few days and hurts most just before it bursts or is drained. Frequency varies enormously, and for many they cluster before periods.

Untreated over yearsIf it is left alone
It tends to progress

More sites get involved, single lumps join into tunnels, and tunnels heal into thick rope-like scars that can restrict how an arm or leg moves. This is why you treat early rather than ride out each flare.

Later lifeMidlife and beyond
Many women find it settles after menopause

Stopping smoking, losing weight where that applies, and proper medical treatment all reduce severity. Tunnels removed surgically do not come back, which makes surgery worth considering rather than a last resort.

What Makes It Better & Worse

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It is not one problem, it is four — a follicle plugs, it bursts under the skin, the immune system reacts to what spilled, and repeated cycles leave tunnels and scars. What acts on step four causes permanent change, so address it first even when a flare feels more urgent.

What is driving yours?

FATPOREOILGLANDBARRIEREPIDERMISDERMIS

A hair follicle in a fold fills with keratin, the protein that makes up the outer layer of skin, and the opening blocks. This is why friction, shaving and heat set flares off, and why the condition sits in folds rather than anywhere else.

The blocked follicle keeps filling from below, swells, and gives way sideways into the deeper tissue instead of opening at the surface. That is the moment a lump becomes painful, and it is why squeezing it makes things worse rather than better.

Keratin, oil and ordinary skin bacteria are now deep in tissue where they do not belong, and the immune system reacts hard. That reaction is the pain, the swelling and the pus, and it is why anti-inflammatory treatment works better here than antibiotics used to kill an infection.

When the same area goes through this cycle again and again, the body walls it off with tunnels lined by skin cells, and thick rope-like scars form around them. Tunnels do not close on their own and medication cannot shut them. Almost everything on the lists below is pushing on this step.

What helps

  • Stopping smoking The highest-value change available.
  • An antiseptic wash Benzoyl peroxide or chlorhexidine a few times a week.
  • Hormonal treatment Spironolactone or a combined pill, where flares track the cycle.
  • Metformin Added where there is insulin resistance or polycystic ovary syndrome.
  • Loose breathable clothing Cotton, no waistband over a fold, damp clothes changed promptly.
  • Laser hair removal Removing the hair removes the follicle that plugs.
  • Weight loss where it applies Less friction, less background inflammation.

What makes it worse

  • Smoking The clearest avoidable factor, and it acts on the disease itself.
  • Friction and tight clothing Waistbands, seams, tight jeans and underwire set flares off.
  • Shaving and waxing the area Both irritate the follicle and cause ingrowns.
  • Heat and trapped sweat Hot weather, and damp gym gear left on.
  • Excess weight More friction, more affected folds, more background inflammation.
  • Hormonal shifts Many people flare reliably the week before a period.
  • Deodorants and antiperspirants Fragrance or alcohol on inflamed skin irritates.

What makes it worse

  • Squeezing or lancing at home Pushes the contents sideways and helps a tunnel form.

What helps

  • Topical clindamycin An antibiotic lotion for mild disease, with benzoyl peroxide.
  • Oral tetracycline antibiotics Doxycycline or lymecycline, for the anti-inflammatory effect.
  • Clindamycin with rifampicin Two antibiotics together for moderate disease.
  • Biologic injections Adalimumab and secukinumab act on the driving immune signals.
  • A steroid injection into a lump Settles one painful flare within a day or two.
  • Warm compresses Ease pain and help a lump come to a head.

What makes it worse

  • Stress and poor sleep Both raise background inflammation.
  • Stopping treatment when it works Control is maintenance. Flares return within weeks to months.

What helps

  • Deroofing Removes a tunnel's roof. It does not come back.
  • Wide excision Removing a whole affected area, for advanced disease.
  • Absorbent dressings Not treatment, but the right dressing changes daily life.

What makes it worse

  • Waiting it out Every untreated year is more chance of tunnels.

How These Treatments Work

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Treatments for Hidradenitis Suppurativa do not all work in the same place. Tap one to see where it acts.

Pick a treatment
Skin basics
BARRIEREPIDERMISDERMISPOREOILGLANDLOWERS THE BACTERIAQUIETS THE IMMUNE SIGNALTURNS THE GLAND DOWNREMOVES THE TUNNELSREMOVES THE TRIGGER

Bacteria are not the cause, but they drive the flares and the smell.

Blocks the immune messages driving the lumps and tunnels, from the inside.

Works upstream, on the hormone signal feeding the follicle.

Once tunnels have formed under the skin, no drug closes them.

These do not cause it, but they decide how often it flares.

The outer film of dead cells and oil. It holds water in and keeps irritants out, and it is thinner than a sheet of paper. Almost every dry, itchy, stinging skin problem starts here.

The outer layer, and the only one anything in a jar reaches. It renews itself constantly: a cell made at the bottom takes about a month to reach the surface and flake off. Most of what a skincare product does, it does here.

The living layer underneath, holding the blood vessels, the nerves and the collagen. It is where lasting change happens and it is hard to reach: most of what is sold for the skin never gets this far.

Over-the-Counter Products

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Everything here you can buy without seeing anyone.

Three acne wash tubes on white: Differin Deep Cleanser, CeraVe Acne Foaming Cream Cleanser and PanOxyl
Benzoyl Peroxide wash
Limited evidence
An antiseptic wash used two or three times a week on the affected folds, lathered and rinsed rather than left on. It lowers the bacteria on the skin and is often paired with clindamycin lotion to stop resistance building. It will not stop lumps forming on its own, and it bleaches towels and dark clothing.
Ibuprofen and acetaminophen
Ibuprofen and acetaminophen
Limited evidence
For flare pain, which is at its worst in the day or two before a lump bursts or is drained. Taken regularly through a flare they work better than taken only at the peak. If they are not touching the pain, that is a reason to be seen rather than to take more, because a steroid injection settles a single lump far faster.
Absorbent dressings
Absorbent dressings
Limited evidence
Not a treatment, but the thing that changes daily life most for anyone with a draining lesion. A soft absorbent pad held with tubular netting or a stretchy vest handles the fluid without an adhesive that tears sore skin. A dermatology nurse can advise which dressing suits which site, and many are available on prescription.
Chlorhexidine wash
Chlorhexidine wash
Limited evidence
An alternative antiseptic wash for the folds if benzoyl peroxide is too drying or bleaches too much. Same use: lather, rinse, a few times a week. It reduces the odor some people find hardest to live with. It does nothing about the inflammation underneath, so it is a support rather than a treatment.
Zinc supplements
Zinc supplements
Weak evidence
Oral zinc is often suggested online for this condition. The studies behind it are small and uncontrolled, and it has not been shown to change flares in any reliable way. High doses upset the stomach and interfere with copper absorption over time. Worth mentioning to your doctor rather than starting alone.

Prescriptions

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These need a prescription.

A white metal tube lying at an angle on a white background, white ribbed cap to the left, labeled Clindamycin in black lettering with a teal swoosh curving beneath the word.Diagram: how Clindamycin works in the skin
Strong evidence
A twice-daily antibiotic lotion for mild disease, the one topical here with real trial evidence behind it. It reduces the number of lumps and abscesses, and in early disease works about as well as tetracycline tablets. It is nearly always paired with a benzoyl peroxide wash, because clindamycin used alone breeds resistant bacteria.
A white cream tube lying on its side on a white background, with a plain white label reading Resorcinol and a blue swoosh beneath it.
Resorcinol 15% cream
Limited evidence
A peeling cream dabbed on a building lump to help it open and settle faster, made up by a compounding pharmacy. Some people find it shortens a flare noticeably. It stings, it can leave a temporary dark stain on deeper skin tones, and it only goes on the lump itself, not across the whole fold.
An amber prescription bottle lying on its side on a white background with a plain white label reading Doxycycline, and six small round white tablets spilled out in front of it.Diagram: how Doxycycline works in the skin
Moderate evidence
A tetracycline antibiotic taken for two to three months, used here for its anti-inflammatory effect rather than to kill an infection. That is why the course is months rather than a week. It reduces flares for many people with mild to moderate disease, and it generally stops working once it is stopped. Take it with water and stay upright afterwards, and expect to burn more easily in the sun.
An amber prescription bottle lying on its side on a white background with a plain white label reading Antibiotics, and six small round white tablets spilled out in front of it.
Clindamycin with rifampicin
Moderate evidence
Two antibiotics taken together for a set ten to twelve week course in moderate disease, usually when tetracyclines have not held. The combination works better than either alone. Rifampicin turns urine and tears orange, stains soft contact lenses, and interferes with several medicines including the contraceptive pill, so the doctor needs your full medicine list.
An amber prescription bottle lying on its side on a white background with a plain white label reading Spironolactone, and six small round white tablets spilled out in front of it.Diagram: how Spironolactone works in the skin
Limited evidence
A hormonal tablet that suits people whose flares track the menstrual cycle. The evidence is from clinics rather than large trials, but the response in the right person can be very good. It takes three to six months to judge, it raises potassium so blood tests are needed, and it must not be used in pregnancy.
A silver blister pack photographed flat on a white background, holding twenty-eight tablets in four rows of seven. The top three rows are white and the bottom row is pale peach, which is the week of inactive pills.Diagram: how Birth Control Pills works in the skin
Limited evidence
A combined pill can reduce flares that cluster before periods, and it is often used alongside spironolactone rather than instead of it. Progesterone-only methods sometimes make the condition worse. Smoking matters here in two ways: it worsens the disease and it also rules out the combined pill for many people over 35.
An amber prescription bottle lying on its side on a white background with a plain white label reading Metformin, and six small round white tablets spilled out in front of it.
Metformin
Limited evidence
A diabetes tablet sometimes added where there is insulin resistance, polycystic ovary syndrome or metabolic syndrome alongside the skin disease. Small studies show fewer flares in that group. It is an add-on, not a main treatment, and it commonly upsets the stomach for the first few weeks.
16:9 hero for Prednisone. Never cropped: the tone strip and the corner logo depend on the full frame.Diagram: how Prednisone works in the skin
Limited evidence
A short course of steroid tablets to break a severe flare while a longer-term treatment is being arranged. It works quickly. It is not a way to manage this condition, because flares return as the dose comes down and repeated courses cause weight gain, bone loss and blood sugar problems.
A white blister pack photographed flat on a white background, holding eight white oblong capsules in two rows of four under clear domes. ACCUTANE is printed in blue capitals on the empty left half of the foil.Diagram: how Accutane works in the skin
Weak evidence
Isotretinoin transforms severe acne, so it is a fair question here. It works much less well for this condition, which starts in the follicle but is not driven by oil, and many people are no better on it. Acitretin, a related tablet, has slightly better results. Neither can be used in pregnancy.
A silver and dark pink autoinjector pen labeled Humira lying on a white background16:9 hero for Adalimumab (Humira). Never cropped: the tone strip and the corner logo depend on the full frame.
Strong evidence
The first biologic licensed for this condition, given as a self-injection under the skin every week or two. It blocks one of the immune signals driving the disease and reduces lumps and abscesses in moderate to severe cases. It does not close existing tunnels. You are screened for tuberculosis and hepatitis first, and infections need reporting while you are on it.
A white injector pen on a white background, with a plain white label reading Secukinumab and a blue swoosh beneath it.
Cosentyx
Strong evidence
A newer biologic injection that blocks a different immune signal, licensed for this condition after trials in moderate to severe disease. It is the usual next step when adalimumab has not worked or has stopped working. Like adalimumab, it treats the inflammation rather than the tunnels, so it is often combined with surgery.

Procedures

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These are done in the office, usually over several visits.

Deroofing
Moderate evidence
The roof of a tunnel is removed under local anesthetic and the floor is left to heal open. The tunnel does not come back in that spot. It is small, done in clinic, and leaves a flatter result than cutting a wide block of skin out, which matters more on deeper skin tones. It treats the tunnels you have, not the disease, so medication usually continues.
16:9 hero for Surgical Excision. Never cropped: the tone strip and the corner logo depend on the full frame.
Wide excision
Moderate evidence
A whole affected area is removed surgically, for advanced disease where tunnels run right across an armpit or groin. Disease does not return in the removed area, though it can appear at the edges or in another fold. It is done in an operating theatre, healing takes weeks, and the area may need a skin graft or flap.
16:9 hero for Laser Hair Removal. Never cropped: the tone strip and the corner logo depend on the full frame.Diagram: how Laser Hair Removal works in the skin
Moderate evidence
Removing the hair removes the follicle that plugs, and several courses of treatment reduce flares in early disease. It works best on Hurley stage one and two, before tunnels form. On deeper skin tones the device matters: the long-pulsed Nd:YAG is the usual choice, and the wrong laser causes burns and pigment change. Ask which one the clinic will use.
Incision and drainage
Limited evidence
Cutting a swollen abscess open relieves severe pressure and pain quickly, which is why it is done in emergency departments. It does not change the course of the condition and the lump usually refills in the same place within weeks. Repeated draining of the same spot encourages a tunnel to form, so it is a rescue measure rather than treatment.
A gloved clinician injecting a raised lump on a patient's shoulder with a small syringeA small clear glass vial with a metal crimped cap lying on a white background, with a clear plastic syringe and a fine sheathed needle resting against it.
Limited evidence
A small amount of steroid injected straight into a single painful lump, which usually settles it within a day or two. It is the fastest thing available for one bad flare and it avoids cutting. It treats that one lump only, and repeated injections in the same spot can thin the skin, so it is not a plan on its own.

When to See a Dermatologist

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Push for this far sooner than most people come in, because how early it is treated is the best predictor of how it turns out, and most people wait years for the name. Book if a painful lump has come back in the same armpit, groin, buttock or under-breast fold more than twice, if lumps drain or smell, if you can feel a firm cord or tunnel between two spots, if scars are forming, if repeated antibiotic courses give no lasting improvement, or if pain or dressings are affecting work, sleep or relationships. Ask for a dermatology referral and use the name, because it is diagnosed on the pattern rather than a test, and get urgent care if a flare comes with fever, spreading redness or feeling unwell, or if pain stops you moving the limb or sitting down. No blood test, scan or swab diagnoses this — it is the right lesions, in the right places, coming back two or more times in six months — and you should leave with a name, a stage and a plan that is not another course of antibiotics.

— Dr. Schwarz, Board Certified Dermatologist

Complications

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Scarring and restricted movement

Years of flares in the same fold leave thick, rope-like scars that pull the skin tight. In an armpit that can limit how far the arm lifts; in the groin it can make sitting or walking uncomfortable. Scars cannot be reversed with medication, so the way to avoid them is to get on proper treatment early. Surgery can release or remove a badly scarred area.

Depression and anxiety

Constant pain, drainage, dressings and the smell wear people down, and rates of depression and anxiety in this condition are high. It is a normal response to a hard illness, not a separate weakness. It is also rarely asked about, so it is worth raising yourself at an appointment. Getting the skin under control usually helps a great deal, and support for the mood side can be arranged at the same time.

Squamous Cell Carcinoma

A rare complication of very long-standing disease, usually after decades of tunnels and scarring on the buttocks or groin. A skin cancer can grow in the damaged skin. The warning sign is a lump, ulcer or growth that behaves differently from your usual flares and does not settle. Anything like that should be looked at and biopsied rather than treated as another flare.

Lookalikes

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Folliculitis

Both start in a hair follicle and both make tender red bumps in the armpit or groin, and a single early lump is very often called a boil. Ordinary folliculitis and boils clear up and do not come back in the same spot, sit anywhere on the body, and respond to a week of antibiotics. Hidradenitis returns to the same fold again and again, forms tunnels, and gets better with anti-inflammatory treatment rather than short antibiotic courses.

Epidermal Inclusion Cyst

A cyst is also a lump under the skin that can swell, hurt and drain smelly material, and cysts turn up in the same folds. A cyst is usually a single lump that has been there quietly for a long time, often with one dark opening on top, and it settles once it is removed. Hidradenitis brings repeated lumps in the same area, paired blackheads and tunnels between the lumps.

Ingrown Hairs

Shaved and waxed skin in the groin and armpit gets sore red bumps where a hair curls back into the skin, and these are often blamed for the first hidradenitis lumps. An ingrown hair is shallow, you can often see the trapped hair in it, and it settles within days once the hair is freed. Hidradenitis lumps sit deep, last a week or more, and come back in the same fold whether or not you shave.

Myths

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  • "It is caused by poor hygiene." No, and this belief does the most damage. It starts in the hair follicle and is driven by the immune system. Washing more does not prevent it; washing harder makes inflamed skin worse.
  • "They are just boils." A boil is a one-off infection of one follicle that clears and does not return. These recur in the same folds, form tunnels, and are driven by inflammation, not infection. That changes the whole treatment plan.
  • "It is a staph infection." Swabs frequently grow nothing, or ordinary skin bacteria. Antibiotics help mostly through their anti-inflammatory effect, which is why they run for months, not the week you would use for an infection.
  • "It is contagious." It cannot be passed to a partner, a family member or anyone sharing a towel or pool, and it is not a sexually transmitted infection.
  • "Antibiotics will cure it." They control it while you take them, and it returns when you stop. Nothing cures it, though tunnels removed surgically are gone for good.
  • "Just lose weight and it will clear." Weight loss reduces severity and is worth doing, but plenty with this condition are not overweight, and being told it is a weight problem is why many stop seeking care.
  • "Deodorant causes it." No good evidence. Fragranced products sting inflamed skin, so fragrance-free is more comfortable, but stopping deodorant does not stop the condition.
  • "Nothing can be done." That was closer to true twenty years ago. Between hormonal treatment, biologics and small procedures most people improve substantially. The gap between what is possible and what is offered is the real problem.

Questions Patients Ask

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Is this contagious?

No. It cannot be passed through skin contact, towels, swimming pools or sex. It starts in your own hair follicles and is driven by your own immune system.

Why do antibiotics stop working?

They were never killing an infection. Tetracyclines are given for months here because they calm inflammation, and the effect fades when they stop. If antibiotics are not holding, move up to hormonal treatment or a biologic.

Will I need surgery?

Only if tunnels have formed, and not everyone reaches that stage. Medication treats inflammation but cannot close a tunnel, so once one exists a small procedure called deroofing is often the cleanest answer. It is done under local anesthetic and the tunnel does not return.

Does losing weight fix it?

It helps, and it does not fix it. Losing weight reduces friction, reduces affected folds and lowers background inflammation, and many notice fewer flares. But people of every size get this, and treating it as a weight problem is one reason people are sent away without proper treatment.

Can I still shave or have laser hair removal?

Shaving and waxing tend to provoke flares, so clipping is better day to day. Laser hair removal often reduces flares by removing the follicle and is worth considering, particularly in early disease. On deeper skin tones the device matters — ask which laser will be used.

Will it affect having children?

The condition does not affect fertility, but several treatments are not suitable in pregnancy, including some antibiotics and hormonal treatments. Many find it flares in pregnancy and improves afterwards, or the reverse. Plan ahead with the doctor managing your pregnancy, and never start or stop a medicine on your own.

References

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