Hidradenitis suppurativa or acne inversa
Do you have painful lumps or abscesses under your armpits or in the groin?
Photo: © vladimirfloyd / stock.adobe.com
Author: Dr. Johannes Bisschoff · Last updated: 11 October 2026
If so, you may have hidradenitis suppurativa, also called acne inversa. It affects quality of life more than many other skin conditions.
What causes acne inversa and how is it treated? You will find answers here:
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Why do creams and tablets for normal acne not also help with this condition?
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What are the new treatment options for hidradenitis suppurativa?
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What is acne inversa?
Acne inversa (hidradenitis suppurativa) causes chronic inflammation and pus-filled abscesses in the armpits, groin, genitals or buttocks. They are persistent, do not heal on their own and are very painful. In advanced stages, scars also limit movement, on top of the pain.
If you notice these signs in yourself or a family member, please see a dermatologist soon. Changes like this should always be checked by a doctor.
Studies show that acne inversa is one of the skin conditions with the greatest impact on quality of life. The pain is intense and affects very sensitive parts of the body. Because these areas are taboo, many patients feel ashamed, which affects both their social life and their sex life.
Few people have heard of acne inversa, but it is not rare. An estimated up to 2% of the population have it. Studies show that it takes an average of seven years from the first symptoms to a diagnosis.
Many people only see a doctor when an area is acutely inflamed and painful. Often only the acute flare is treated, and the underlying condition is not recognised or treated properly.
Instead, patients are often diagnosed with acne, folliculitis (inflammation of the hair roots) or a single acute abscess, and the chronic abscess disease is missed. Treatment then often does not work, and patients are left frustrated and discouraged. Many suffer in silence, believing nothing can be done. The condition varies a lot from person to person. Researchers are working on classifying different types, but there are no reliable models yet. What we do know: more women than men are affected, it occurs in all skin types, and it seems to run in families, since blood relatives are often affected too.
What causes acne inversa?
Acne inversa (hidradenitis suppurativa) is a chronic inflammatory skin disease whose exact causes are not yet fully understood. At its core are changes in the hair follicles and an excessive inflammatory response of the immune system.
It is considered likely that a keratinisation disorder of the hair follicle leads to a blockage of the follicular duct. Over time, the hair follicle ruptures beneath the skin surface, causing painful inflammation.
Acne inversa is not classified as a classic autoimmune disease. Rather, it is an immune-mediated inflammatory disease in which various inflammatory messenger substances play an important role.
This understanding has led to targeted treatments. In moderate to severe acne inversa, biologics can be used under certain conditions. In the EU, the active substances adalimumab, secukinumab and bimekizumab, among others, are approved for this.
Acne inversa is neither contagious nor a result of poor hygiene.
Acne inversa differs from "normal" acne (acne vulgaris) in where it appears: acne vulgaris shows up on the face, chest or back. Acne vulgaris also involves increased sebum production. What both have in common is that the hair follicle becomes blocked with keratin.
Acne inversa, on the other hand, affects skin folds, usually in the groin, armpits or genital area. The face is very rarely involved. Blood relatives often have the condition too, to varying degrees. It starts with red, painful, inflamed nodules that later turn into abscesses. It comes in intense flare-ups, and permanent scarring is possible. The impact on everyday life is an extra burden. The chronic inflammation also puts stress on the whole body, and over time other symptoms may appear that point to additional conditions.
Which factors influence acne inversa?
Several factors play a part in how acne inversa develops and progresses. Doctors distinguish between a person's predisposition and influences that can make it worse.
Genetic predisposition: Acne inversa occurs more frequently in some families. A family predisposition can increase the risk of developing acne inversa. However, it does not automatically mean that the disease will occur, and it is not a direct trigger of individual flare-ups.
Smoking and excess weight: Both are linked to acne inversa and sometimes to more severe disease. Quitting smoking and losing weight if you are overweight can therefore be an important part of treatment.
Mechanical friction and sweating: Friction, pressure and moisture in sensitive skin areas can aggravate existing symptoms. Loose, breathable clothing can help avoid additional skin irritation.
Stress and hormonal influences: Some patients report that their symptoms worsen during stressful periods or in connection with hormonal changes. These relationships vary from person to person and are not yet fully understood scientifically.
Important: Acne inversa is not caused by a single factor. People who do not smoke, are of normal weight and live a healthy lifestyle can also develop acne inversa.
How is acne inversa diagnosed?
Acne inversa (hidradenitis suppurativa) is diagnosed primarily through a dermatological examination. Experienced dermatologists usually recognise the condition by its characteristic skin changes, typical locations and recurring course.
Three key criteria are decisive for the diagnosis:
1. Typical skin changes
Acne inversa often presents as painful, deep-seated nodules and recurring abscesses. Over time, inflammatory tunnels under the skin (fistulas), scars and so-called double comedones (blackheads occurring in pairs) can develop.
2. Typical body regions
Areas where skin touches skin are most frequently affected, including:
- Armpits
- Groin and genital area
- Buttocks and gluteal cleft
- Area beneath the breasts
- Perineal and anal region
However, the condition can also occur in other parts of the body.
3. Recurring or chronic course
A characteristic feature is that symptoms recur repeatedly or persist over a longer period. New inflammation often develops in the same or neighbouring areas of skin.
Important: Not every recurring abscess automatically means acne inversa. Other skin conditions may need to be ruled out. An early dermatological assessment is therefore particularly important.
How is the severity of acne inversa determined?
Acne inversa does not progress the same way in everyone. Some patients only occasionally develop inflamed nodules, while others experience recurring abscesses, tunnels or pronounced scarring.
To assess the condition as accurately as possible and choose the right treatment, two scoring systems are commonly used: the Hurley classification and the IHS4 score.
Hurley classification: how much has the skin already changed?
The Hurley classification mainly describes permanent tissue changes and distinguishes three stages:
- Hurley stage I: Single or multiple abscesses without detectable tunnels or scarring.
- Hurley stage II: Recurring abscesses with tunnels and scarring. The affected areas are separated by healthy skin.
- Hurley stage III: Extensive or almost diffuse involvement of a body region with interconnected tunnels and abscesses.
This classification is particularly helpful when deciding whether surgery may be useful in addition to medical treatment.
IHS4 score: how active is the inflammation right now?
The International Hidradenitis Suppurativa Severity Score System (IHS4) assesses current inflammatory activity based on the number of inflammatory lesions. Three types of lesions are weighted differently:
- Inflammatory nodules: 1 point
- Abscesses: 2 points
- Draining tunnels: 4 points
The total score indicates the current disease activity:
- 0–3 points: mild disease activity
- 4–10 points: moderate disease activity
- 11 points or more: severe disease activity
The IHS4 score can be repeated over time to assess changes in inflammatory activity and the response to treatment.
Why are both assessments important?
The Hurley classification and the IHS4 score complement each other. While the Hurley classification mainly shows how much the skin has already been structurally changed by the disease, the IHS4 score captures how active the inflammation is at the time of the examination.
For example, a patient may already have pronounced scars and tunnels even though only a few inflamed nodules are currently present.
Treatment of acne inversa is therefore tailored to each individual. In addition to the Hurley stage and the IHS4 score, we take into account factors such as pain, affected body regions, quality of life and previous treatments.
Why is early treatment of acne inversa so important?
The earlier acne inversa is recognised and treated, the better the chances usually are of controlling inflammation and avoiding permanent skin damage.
Acne inversa can progress in different ways. While some patients develop only individual inflamed nodules over a long period, others develop recurring abscesses, tunnels and scars. How the disease will develop cannot always be predicted.
So don't wait too long when you notice the first signs. Before pronounced tunnels or scars have formed, there are often more options for less invasive treatment. Once the skin structure has changed, surgery may be needed as well.
An early diagnosis and the right treatment can reduce inflammation, relieve symptoms and lower the risk of the disease progressing.
Recurring painful nodules or abscesses should therefore be checked by a dermatologist as early as possible, even if they go away in between.
We help you recognise acne inversa early and work out a treatment plan that fits your condition.
Why don't creams and tablets for normal acne also help with acne inversa?
They are two different conditions with different causes. In acne vulgaris, the extra sebum production is often hormonal, and it does not usually last for decades. Acne inversa, by contrast, often only appears after puberty. Treatments for acne vulgaris, such as high-dose vitamin A or fruit acid peels, do not work for acne inversa.
What treatment is available?
Acne inversa (hidradenitis suppurativa) is a chronic disease. With the right treatment, though, inflammation can be reduced and longer periods with few symptoms are possible. Depending on where and how badly the skin is affected, medication offers a good chance of relief:
- Localized antibiotic treatment for flare ups
- Ointments applied to the acute areas
- Zinc supplements in high dosages (in combination with other treatment methods)
- Oral antibiotic treatment over a longer period (weeks, months), and in the case of severe diagnoses (double antibiosis)
- Androgen blockers (pill) in women
- Hormone treatment, only if prescribed by a specialist and with medical supervision
- Immunosuppressive therapy using antibodies / biologicals in therapy-resistant cases
Surgery can also make sense for limited, recurring lesions, for example as deroofing or local excision, and not only in severe cases. In extensive disease, fistulas and deep nodules can be operated on in a clinic that specialises in acne inversa. All abscesses and nodules, including scar tissue, are removed from the affected areas. The wound then heals openly, which can take two to three months depending on the findings. In many cases this leads to lasting remission, because the new tissue no longer contains hair follicles. However, the disease can flare up again at the edges of the treated areas, or it may already be so advanced that permanent damage cannot be avoided. This can be very distressing, especially when the genital area is affected. Because it is a chronic disease, symptoms may also appear elsewhere after surgery.
Since 2017, LAight® therapy has been available in Europe as a CE-marked medical device for the treatment of acne inversa/hidradenitis suppurativa. This is a classification under medical device regulations, not a marketing authorisation as required for medicines. The therapy is mentioned in the current European S2k guidelines for hidradenitis suppurativa/acne inversa, particularly for mild to moderate disease.
What can I expect from the lAight therapy?
The therapy combines a special light spectrum with radiofrequency. The light reduces inflammation, kills germs and reduces keratin build-up in the hair follicle. The radiofrequency targets the walls of abscesses and fistulas, stimulates new tissue and regulates sebum production. The blocked areas open up and dry out, and existing blackheads (comedones) decline.
Dr. Bisschoff gained a lot of experience with LAight therapy during his specialist training in Hamburg and saw good results in many patients. Used regularly, it is a good option especially for mild to moderate disease and can be combined with medication or surgery when needed.
We have offered LAight therapy at our practice in Vienna since March 2021. Our team includes specially trained medical assistants with a lot of experience in acne inversa and LAight therapy.
What do the latest medical studies say?
Recent studies show that people with acne inversa have a different mix of microorganisms (microbiome) on the skin and in the gut. Based on an analysis of a person's microbiome, a proposal for changing it can be developed. The hope is that this will soon help us understand and treat many conditions that are hard to treat today.
What are the new treatment options for hidradenitis suppurativa?
New treatments keep becoming available. Three antibodies are now approved by the European Medicines Agency (EMA): adalimumab, secukinumab and bimekizumab. They are called biologics, are given by injection and act on the misdirected immune response. Regular check-ups with experienced doctors are important, and all of our doctors are experienced with this treatment.
More medicines are in development. Our practice regularly takes part in studies of new drugs, to help our patients and to support medical research.
Complementary and supportive treatments
Alongside medication and surgery, complementary measures also help in treating hidradenitis suppurativa (acne inversa).
Current guidelines recommend several supportive approaches that can relieve symptoms and have a positive effect on the course of the disease. These include:
- Injection treatment for hyperhidrosis (excessive sweating) to reduce sweat production and possible additional skin irritation.
- Laser hair removal to reduce inflammatory activity in affected skin areas.
- Weight reduction if overweight, which can have a positive effect on disease activity.
- Medication to support weight loss, for example GLP-1 receptor agonists. Early scientific findings suggest that these medicines may also have a positive effect on the course of hidradenitis suppurativa.
At your first consultation our doctors will go through the complementary treatments that could help you. Together we put together a treatment plan that covers both the disease itself and supportive measures.
Where can I get more information?
For more about the condition, you can contact the Mullewupp e.V. support group, which does very good educational work. You will find more information and a symptom check for a first assessment at www.akne-inversa.at.
We are happy to draw up a treatment plan with you at our practice.
What can I do myself to relieve the symptoms?
Besides medical treatment, changes to your lifestyle can also affect how severe the symptoms are:
Reducing stress
Avoid irritation of the skin (no tight-fitting clothes, no synthetic materials)
Germ reduction in the affected areas (e.g. disinfectant washing lotion)
Avoid wet shaving (due to the risk of micro lesions and their bacterial colonization)
Weight reduction for anyone overweight
Nicotine avoidance or reduction for smokers
We are happy to help you put together a plan to ease your symptoms.
Request a short-notice appointment here
Dr. Dariana Borlea focuses on the long-term care of chronic inflammatory skin diseases such as hidradenitis suppurativa, psoriasis and atopic dermatitis, and has experience in biologic therapy.
Dr. Lara Durakbaşa combines experience with biologics with extensive surgical expertise, including laser treatments (e.g. laser deroofing).
Dr. Johannes Bisschoff has been involved with hidradenitis suppurativa since his training. In addition to surgical procedures, he also uses biologics and has offered LAight therapy (radiofrequency and light) for many years, having been the first physician to introduce it in Austria.
All of our doctors advise you according to the latest standards and current guidelines.
FAQ: Hidradenitis Suppurativa & Abscess Disorders
Here you will find answers to the most important questions about hidradenitis suppurativa, risk factors, self-management and modern treatment options.
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What is hidradenitis suppurativa?
Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease that causes painful nodules, abscesses, fistulas and scarring, mainly in the armpits, groin, buttocks and genital area.
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What causes hidradenitis suppurativa?
The exact cause is unknown. Factors include follicular occlusion, genetics, bacterial colonization, obesity, smoking and friction in skin folds.
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Why don’t regular acne creams work?
HS does not affect facial oil glands like "normal acne" but deep follicular structures in skin folds, so standard acne treatments are largely ineffective as the cause is different for both diseases.
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What treatment options are available?
Treatments include permanent hair-removal, topical and oral antibiotics, hormone therapy in women, biologics for severe cases, surgical removal of nodules and the LAight® therapy for mild to moderate HS.
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Which risk factors worsen HS?
Key risk factors include obesity, smoking, friction, family history and stress. These factors increase inflammation and flare-ups.
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Can hidradenitis suppurativa be cured?
A complete cure is currently not possible. Treatment focuses on long-term inflammation control, pain reduction and preventing scarring and relapses.
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What can I do myself to reduce symptoms?
Stopping smoking, losing weight, using antiseptic skincare, avoiding tight clothing and friction, avoiding wet shaving in affected areas and reducing stress can help.
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Where can I go for consultation and treatment if I suffer from hidradenitis suppurativa?
Hidradenitis suppurativa is a complex chronic condition that often requires several treatment approaches at the same time. For this reason, it is recommended to seek care at a specialized center with a clear focus on HS. Such centers provide comprehensive counselling, guideline-based diagnostics and individualized treatment plans. Since HS is a progressive disease, every day counts – early treatment greatly improves long-term outcomes.
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How does a dermatologist recognise hidradenitis suppurativa?
A dermatologist recognises acne inversa (hidradenitis suppurativa) primarily on the basis of the medical history and a thorough examination of the skin. Three typical criteria are decisive for the diagnosis:
- Typical skin changes: Recurring, painful, deep-seated nodules and abscesses, and possibly tunnels (fistulas) and scars.
- Typical body sites: The changes occur mainly in the armpits, the groin, the genital and anal area and beneath the breasts.
- Chronic or recurring course: The inflammatory skin changes recur, for example at least twice within six months.
If all three criteria are met, this points to acne inversa. Additional examinations such as ultrasound can help detect deeper inflammation and tunnels. A blood test alone cannot confirm acne inversa.
You can find more information in the section “How is acne inversa diagnosed?”.
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What are the stages of hidradenitis suppurativa?
The severity of acne inversa is often classified into three stages using the Hurley classification. The presence of tunnels (fistulas) and scars and the extent of the affected skin areas are particularly important.
- Hurley stage I: Single or multiple inflamed nodules and abscesses, but without tunnels or disease-typical scarring.
- Hurley stage II: Recurring abscesses with tunnels and scars. The affected areas of inflammation are separated from each other.
- Hurley stage III: Extensive skin changes with numerous interconnected tunnels and abscesses covering large parts of an affected body region.
The Hurley classification helps the dermatologist assess the extent of the disease and plan suitable treatment. As it mainly reflects tissue changes that have already developed, it does not necessarily describe current inflammatory activity.
You can find more about the classification in the section “How is acne inversa diagnosed?”.
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What does the IHS4 score mean in hidradenitis suppurativa?
The IHS4 score (International Hidradenitis Suppurativa Severity Score System) is a scoring system that dermatologists use to assess current inflammatory disease activity in acne inversa.
Three types of skin lesions are counted and weighted differently:
- Inflammatory nodules: number × 1
- Abscesses: number × 2
- Draining tunnels: number × 4
The sum gives the IHS4 value, which is classified as follows:
- 0–3 points: mild disease activity
- 4–10 points: moderate disease activity
- 11 points or more: severe disease activity
Unlike the Hurley classification, which mainly describes structural skin changes, the IHS4 score can reflect changes in current inflammatory activity over the course of the disease. It is therefore also used to assess the response to treatment.
You can find further details in the section “How is acne inversa diagnosed?”.
More Information:
1) Our article on LAight® Therapy is online - LAight® Therapy Improves Hidradenitis Suppurativa in Patients Declining Surgical Intervention: Two Case Reports
2) Guidelines: European S2k guidelines for hidradenitis suppurativa/acne inversa (Journal of the European Academy of Dermatology and Venereology)
3) ACNE INVERSA: INTERVIEW WITH DR. JOHANNES BISSCHOFF
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