What Is Hidradenitis Suppurativa?
Hidradenitis suppurativa (pronounced hid-rad-en-EYE-tis sup-yoo-ruh-TIE-vuh), also known as HS or acne inversa, is a chronic inflammatory skin disease that causes painful lumps, abscesses, and tunnels to form deep in the skin. It primarily affects areas where skin rubs against skin, the armpits, groin, inner thighs, buttocks, and under the breasts.
HS is not contagious, not caused by poor hygiene, and not simply "bad acne." It is a systemic inflammatory condition driven by immune system dysfunction, with the skin as the primary site of visible disease. The condition was first described in medical literature in the 1800s, yet it remains significantly underdiagnosed and undertreated today.
Key Facts About HS
This guide is for educational purposes. Always consult a board-certified dermatologist for diagnosis and personalized treatment.
Causes and Risk Factors
HS develops from a complex interplay of genetic predisposition, immune system dysfunction, and environmental triggers. Understanding the causes helps explain why HS behaves the way it does, and why certain treatments work.
The Biological Mechanism
The disease begins with follicular occlusion, the hair follicle becomes blocked, trapping keratin and bacteria. This triggers an intense inflammatory response that ruptures the follicle, spreading inflammation into the surrounding tissue. The immune system then mounts an exaggerated response, involving cytokines like TNF-alpha, IL-1, IL-17, and IL-23, which drive the chronic inflammation characteristic of HS.
Risk Factors
| Risk Factor | Impact | Notes |
|---|---|---|
| Family history | High | ~40% of patients have an affected relative; several gene mutations identified |
| Female sex | High | 3x more common in women; hormonal factors play a significant role |
| Smoking | High | Smokers have more severe disease; nicotine affects follicular keratinocytes |
| Obesity/overweight | High | Mechanical friction + metabolic inflammation; weight loss can improve symptoms |
| African descent | Moderate–High | Higher prevalence and often more severe presentation |
| Metabolic syndrome | Moderate | Insulin resistance, diabetes, and PCOS are associated with HS |
Symptoms and Diagnosis
HS produces a characteristic set of symptoms that, when recognized together, distinguish it from other skin conditions. The hallmarks are recurrence in the same locations, formation of sinus tracts, and progressive scarring.
Diagnosis is clinical, based on history and physical examination. There is no blood test or biopsy that definitively diagnoses HS. The diagnostic criteria require: (1) typical lesions (nodules, abscesses, sinus tracts, scars), (2) typical locations (axillae, groin, perineum, inframammary), and (3) recurrence (at least 2 episodes in 6 months).
For a detailed breakdown of every HS symptom, see our HS Symptoms Guide. For visual descriptions of what HS looks like, see What Does HS Look Like?
HS Stages (Hurley Classification)
HS severity is classified using the Hurley Staging System into three stages. Your stage guides treatment decisions and helps track disease progression.
Isolated abscesses, no sinus tracts, minimal scarring. Responds to topical and oral treatments.
Recurrent abscesses with sinus tracts and scarring. Requires systemic treatment, often biologics.
For the complete stages guide with treatment recommendations, see Hidradenitis Suppurativa Stages.
Treatment Options
HS treatment has advanced dramatically in recent years. The current approach is multimodal, combining medical therapy, lifestyle modification, and in some cases surgery. Treatment is always individualized based on disease stage, severity, and patient response.
For a complete treatment guide including flare management protocols, see HS Flare Treatment and our How to Manage HS Flares guide.
Lifestyle Management
Lifestyle modifications are a critical complement to medical treatment. While they cannot replace medication, they can meaningfully reduce flare frequency and severity.
Diet
Reduce dairy and high-glycemic foods; emphasize anti-inflammatory eating
Smoking Cessation
Smoking is one of the strongest modifiable HS risk factors; cessation often improves disease activity
Weight Management
Even modest weight loss can reduce friction, improve metabolic factors, and decrease flare frequency
Stress Management
Psychological stress is a documented HS trigger; mindfulness and therapy can help
Clothing Choices
Loose, breathable fabrics reduce friction and sweating, key HS triggers
Wound Care
Proper daily wound care prevents secondary infection and reduces odor
Mental Health and HS
The psychological burden of HS is profound and often underestimated. Studies consistently show that HS has a greater impact on quality of life than many other chronic skin conditions, including psoriasis. Depression affects up to 40% of HS patients, and anxiety is similarly prevalent.
Mental health support should be considered an essential component of HS care, not an optional add-on. Cognitive behavioral therapy (CBT), mindfulness-based stress reduction, and peer support groups have all shown benefit for chronic illness patients.
If you are struggling
You are not alone. The HS community is large, supportive, and understands what you are going through in a way that people without HS simply cannot.
Surgery for HS
Surgery is an important tool in the HS treatment arsenal, particularly for patients with established sinus tracts and scarring that do not respond adequately to medical therapy. The goal of surgery is to remove affected tissue, eliminate tunnels, and provide long-term relief.
The main surgical options range from simple deroofing (removing the roof of a sinus tract) to wide local excision (removing all affected tissue in a region). Surgery is most effective when combined with ongoing biologic therapy to prevent recurrence in new areas.
For a complete guide to HS surgery and recovery, see our HS Surgery Patient Guide and HS Surgery Recovery page.
Research and Future Treatments
HS research has accelerated dramatically in the past decade. The approval of adalimumab in 2015 opened the door to a new era of biologic treatments, and several additional biologics have since been approved or are in late-stage clinical trials.
Current areas of active research include: new biologic targets (IL-36, JAK inhibitors), combination therapy approaches, biomarkers for treatment response prediction, and the role of the skin microbiome in HS. The pipeline for new HS treatments has never been more robust.
For the latest research updates, visit our Research page and the HS Research Updates blog.
Frequently Asked Questions
What is hidradenitis suppurativa?
How common is hidradenitis suppurativa?
Is hidradenitis suppurativa curable?
What causes hidradenitis suppurativa?
When should I see a doctor for HS?
Stay Updated on HS
New research, treatment updates, and community support, in your inbox monthly.
No spam, ever. Unsubscribe anytime.