Hidradenitis Suppurativa (HS) is a chronic, inflammatory skin disease characterized by painful nodules and abscesses which form most commonly in sensitive areas: under arms and breasts, along buttocks and groin, though HS may appear anywhere there is hair.

When symptoms first appear, they appear as painful, recurrent pimples or cysts in telltale areas. Because of its appearance and location, HS is often misdiagnosed as ingrown hairs, folliculitis, staph infection, cellulitis, or an STD. But unlike those conditions, HS cannot be cured and the lesions left behind will often refill, have difficulty healing, and leave behind scars.

Women are diagnosed with HS 3x more often than men and their symptoms tend to start around puberty or other times of hormonal changes like pregnancy, postpartum, or changes in hormonal birth control.


Hidradenitis Suppurativa (HS) is a clinical diagnosis, which means that a doctor cannot run a test to determine if you have HS.   A doctor will look for these signs and symptoms to determine if it is HS or a different, similar-presenting condition.

  • Have you had painful, swollen bumps that may look like boils or large pimples on your chest, underarms, groin, buttocks, or thighs?
  • Did those bumps reappear in those areas 3 or more times?
  • Did these bumps leave behind scars?
  • Do the bumps appear symmetrically – for example under both arms, or on both thighs?
  • In the same area where you get these bumps, do you also get comedones (blackheads)?

While diagnosing HS, doctors may also swab the affected area to rule out bacterial infection.  As a specialist in skin conditions, a dermatologist would be most familiar with the signs and symptoms of HS.


HS typically goes undiagnosed for years because patients are ashamed to speak with anyone. When they do see a doctor, the disease is frequently misdiagnosed.  It is reported that patients 15 doctors visit over 7 years before achieving the correct diagnosis.

Historically, HS has been considered a rare disorder, because it is difficult to accurately estimate the number of people living with HS; they conceal their condition, even from friends and close relatives. However, when all stages of the disease are considered, it is estimated that 1-4% of the population – potentially up to 13 million Americans alone – have Hidradenitis Suppurativa.


Hidradenitis Suppurativa typically develops slowly over time.  Development differs, however, from individual to individual.  Most patients with HS (an estimated 2/3rds) will never develop past a mild stage.  With others, it may escalate and become a debilitating disease.   It is not known why.

The severity of an individual’s HS is commonly measured by Hurley Stages:

Stage I (“Mild”): Solitary or multiple isolated abscess formation without sinus tracts

Stage II (“Moderate”): Recurrent abscesses, single or multiple widely separated lesions, with beginning sinus tract formation (“tunneling”)

Stage III (“Severe”): Diffuse or broad involvement across a regional area with multiple interconnected sinus tracts, significant scarring and persistent abscesses

The Hurley staging system was developed by Dr. H J Hurley, a dermatologist and surgeon looking to classify which patients would benefit from excision surgery in the management of their HS.  Unfortunately, while this staging system is still widely in use today, it does not accurately measure activity (for example, once you have one sinus tract, you cannot go back down to Stage I without surgical excision).  HS experts around the world, with direction and involvement from patients, are currently working together to develop a more accurate, reliable way to measure HS severity and activity.


First and foremost, Hidradenitis Suppurativa (HS) is NOT contagious, nor is it caused by poor hygiene.

Doctors are still unsure of the causes of HS, but a malfunctioning immune system, genetics, hormones, unique anatomy of hair follicles, skin microbiome, and environmental triggers are all considered factors for HS.


Hidradenitis Suppurativa is NOT contagious.  The lesions and spots may resemble conditions which people associate with being contagious, but HS is not contagious.

Hidradenitis Suppurativa is NOT acne.  When the symptoms of HS first appear, some people may think that they have a form of severe below-the-belt acne.  Compounding this confusion is that in some parts of the world, HS is referred to as “acne inversa.”  Some treatments for HS are used in acne, but that is where the similarities end.

Hidradenitis Suppurativa is NOT caused by poor hygeine.  HS may resemble conditions like furuncles or boils to the untrained eye, but bathing routines do not cause nor cure HS.  Individuals living with HS grapple with the fear of stigmatization every day, and the misconception that HS is associated with poor hygiene is among the biggest myths.

Hidradenitis Suppurativa is NOT an STD.  Because HS can often appear in the groin area, people are often concerned that their partners may think they have a sexually transmitted disease.  And while the causes of HS are not yet fully understood, it is very clearly NOT an STD nor is it contagious.

Hidradenitis Suppurativa is NOT caused by smoking and overweight.  No one disputes that smoking or excess weight is bad for long-term health.  But HS doesn’t begin with weight and smoking, nor is it cured by ending smoking or losing weight.  Patients are diagnosed at every stage in every body type.  Many patients have no history of smoking.  Studies show a correlation between smoking and obesity with HS, but they have not shown a causative link, nor have they demonstrated that weight loss or smoking cessation will improve one’s HS.  Patients report daily that smoking cessation or weight loss makes their condition worse, but this poor advice continues to be offered to patients as a fix for all of their HS symptoms.

Pain from HS affects a patient’s mobility and energy levels, making it harder to be active.  Doctors must first help treat the HS before a patient can undertake exercise or lifestyle changes.


What is the role of apocrine glands?  For many years, HS was referred to as a disease of the aprocine glands.  Apocrine glands are a type of sweat gland that appears in some of the areas where one can find HS spots – like the underarm and groin – but also in areas where HS spots are nearly unheard of – like the ear canal, eyelids, and nostril.  Patients will also report having HS flare-ups in areas where there are no apocrine glands, like the abdomen, or thighs.

Science is not settled on this subject, but it is now thought that Hidradenitis Suppurativa is primarily a disease of the hair follicle and apocrine glands only become secondarily infected.  Sources calling HS a disease of the aprocine glands are out of date and not to be trusted.

Why do some treatments work for some, but not for others?  Hidradenitis Suppurativa is one of the most difficult diseases in dermatology, in no small part because what works for one patient may not work for another.  In fact, some treatments for HS are widely reported by some patients to make their condition worse!

Triggers also vary between individuals, also observing opposite reactions to some triggers.  For example, many women report going into remission during pregnancy and others report it being worse than ever!  Some report being “cured” of their HS with menopause, some women only begin to get symptoms with the onset of menopause.  This is not understood, but experts theorize that there are many factors that contribute to HS and each factor may play a bigger or smaller role, depending entirely on the individual.

Are there different “types” of Hidradenitis Suppurativa?  HS is currently not classified by type, but work is being done by HS experts to do just that.  It is theorized that different types of HS may respond differently to treatments, and a classification for each patient’s HS type may help guide better treatment and produce better data on the results of treatment trials.

Is Hidradenitis Suppurativa an autoimmune disease?  The term “autoimmune” seems to mean something different to different audiences.  In popular culture, “autoimmune” is used as short hand to mean any condition which is brought on or exacerbated by a hyperactive immune system. By technical definition, however, autoimmune has to meet the criteria of a malfunction in the adaptive or acquired immune system.

The adaptive or acquired immune system is the part of our immune system responsible for developing antibodies in response to a virus or other immunological threat.  In true autoimmune conditions, the body develops antibodies that attack healthy organs; for example, in MS, the body produces autoantibodies that attack parts of the nervous system while Type I diabetes produces autoantibodies that attack the pancreas.  Hidradenitis Suppurativa researchers have searched for, but never found, biomarkers of the adaptive immune system.  So in the stritctest terms, Hidradenitis Suppurativa is not an autoimmune disease.

Hidradenitis Suppurativa is, however, an inflammatory disease.  There are regularly elevated biomarkers of the innate immune system, like CRP, IL-17, and TNF.  This demonstrates that the immune system is involved, but does not meet the strictest requirements to be named an autoimmune disease.

But what difference does it truly make?  It may just be semantics, as autoimmune and autoinflammatory are considered terms on one continuum.  And in time, antibodies for HS could eventually be found.  But either way, patients deserve treatments and relief and a better understanding of HS will lead us there.



A complication is an undesired, sometimes dangerous, evolution or consequence of disease progression.  In HS, the most noteworthy complications are a result of living with chronic, open wounds.

Cellulitis Cellulitis is a bacterial infection of the skin.  Although HS is not caused primarily by bacteria, all humans carry normal skin bacteria on their skin and having open wounds (especially squeezing or touching these areas) introduces the opportunity for bacteria to enter the skin where it doesn’t belong, potentially causing cellulitis.

Symptoms of cellulitis are easy to confuse with the symptoms of an HS flare, which include swelling, redness, pain, and warmth of the affected area.  If you suspect that your HS has evolved to cellulitis, you can aid observation by tracing the area with a marker and observing if the redness spreads, as cellulitis will spread faster than an HS flare.  Additional symptoms that indicate medical treatment beyond HS treatment is necessary include a fever, nausea, and malaise if these symptoms do not usually accompany your HS flares.

The best way to prevent cellulitis is to never squeeze your HS nodules, do not self-lance, practice good wound care, and only tend to your wounds with thoroughly clean hands.

Sepsis –  Sepsis is a life-threatening condition that arises when the body’s response to infection causes injury to its own tissues and organs.  In addition to symptoms related to HS and cellulitis, sepsis is frequently associated with fever, rapid breathing and heart rate, confusion, swelling, and low body temperature.

If you suspect sepsis or cellulitis, proceed to an emergency department.  Cellulitis and Sepsis cannot be self-treated.

Squamous Cell Carcinoma (SCC) – is a common type of skin cancer, and is considered the most severe complication of HS.  Extensive scarring from HS is the biggest risk factor, but it is important to bear in mind that less than 3% of HS patients have gone on to develop SCC.  SCC lesions vary widely in appearance and any concerning lesions must be biopsied for diagnosis.  Regular skin checks, especially in areas with a lot of scarring, are the best way to prevent SCC.


Several diseases have been observed to accompany a diagnosis of Hidradenitis Suppurativa.  This is known as a comorbidity.  Although someone diagnosed with HS is more likely to have or develop one of the below listed conditions, it is important to note that no causal relationship has been established.  That means that it is not known if one condition causes the other, or if they have a common cause.  More research is needed.

Acne – One of the most obvious associations, but a distinct diagnosis.  HS shares similarities in appearance, and even some overlap in daily over the counter management, but not everyone with HS has had acne and HS is not a form of severe acne.

Pilonidal Cyst

Dissecting Cellulitis

Irritable Bowel Disease

Rheumatoid Arthritis

Poly Cystic Ovarian Syndrome (PCOS)

Metabolic Syndrome and Cardiovascular Disease

Cardiovascular Disease

Squamous Cell Carcinoma & Lymphoma