Hidradenitis suppurativa is a long-term inflammatory skin condition that causes painful lumps, abscesses, and tunnels in areas where skin rubs together, such as the armpits and groin. It is not caused by poor hygiene and it is not contagious. Although it can be uncomfortable and persistent, it is manageable, and today there are more treatments than ever before. In this guide you will learn what hidradenitis suppurativa is, how to recognize its symptoms and stages, what causes it, how doctors diagnose it, and which blood and inflammatory markers can appear on your lab report. You will also find the latest research and clear next steps to discuss with your dermatologist, explained in plain, reassuring language.
What is hidradenitis suppurativa?
Hidradenitis suppurativa, also called acne inversa, is a chronic disease of the hair follicles. Despite the older name, it is not the same as ordinary acne. In this condition, hair follicles in certain areas become blocked and inflamed, then rupture under the skin. This sets off a repeating cycle of painful nodules, pus-filled abscesses, and, over time, scarring and tunnel-like tracts called sinus tracts.
The condition usually begins after puberty, most often between the late teens and the age of 40. Estimates of how common it is vary widely, from well under 1% to around 1 to 2% of people, partly because it is often under-recognized. Women are affected roughly three times as often as men, and it can run in families.
Doctors describe hidradenitis suppurativa as an autoinflammatory condition, meaning the body’s own immune system drives the inflammation rather than an outside infection. That distinction matters: the pus in these lesions does not mean the condition is contagious or a sign of being unclean.
How it differs from acne or boils
Because early disease can look like stubborn pimples or recurrent boils, many people live with it for years before receiving a diagnosis. The clue is the pattern: lumps that keep returning in the same skin folds, often on both sides of the body, that are painful and slow to heal. A dermatologist is trained to tell hidradenitis suppurativa apart from an ordinary boil or an acne cyst.
Symptoms and what hidradenitis suppurativa looks like
The symptoms of hidradenitis suppurativa range from mild to severe and tend to come and go in flares. Common signs include:
- Painful, pea-sized lumps, called nodules, deep under the skin that can last for weeks
- Abscesses that swell, break open, and drain pus, sometimes with an odor
- Blackhead-like pitted spots, which often appear in pairs
- Tunnels, or sinus tracts, that connect lumps under the skin and drain fluid
- Rope-like scars that form as lesions slowly heal
These lesions typically appear where skin touches skin and sweat glands are plentiful: the armpits, groin, inner thighs, buttocks, and under the breasts. Flares may be triggered by friction, heat, sweating, stress, or hormonal changes, and some women notice them in the days before their period. The course is highly variable, and many people have only mild disease.
The stages of hidradenitis suppurativa
Clinicians often describe hidradenitis suppurativa using the Hurley staging system, which sorts the condition into three broad stages based on how much scarring and tunneling is present. Staging helps guide treatment, although it is a snapshot rather than a fixed label.
| Stage | What it looks like | General approach |
|---|---|---|
| Hurley stage I | One or a few isolated lumps or abscesses, with no tunnels or scarring | Skin care plus topical or short medical treatment |
| Hurley stage II | Recurring lumps in more than one area, with some tunnels and scarring | Combined medical treatment, sometimes with minor procedures |
| Hurley stage III | Widespread lumps, interconnected tunnels, and extensive scarring | Systemic medicines such as biologics, often combined with surgery |
Many people stay in the earlier stages, especially with early treatment. Newer scoring tools, such as the IHS4, help doctors measure how active the disease is over time by counting nodules, abscesses, and draining tunnels.
What causes hidradenitis suppurativa?
The exact cause of hidradenitis suppurativa is not fully understood, but researchers agree it starts when hair follicles become blocked and then rupture, triggering an exaggerated immune response. Genetics, hormones, and immune signaling all appear to play a part, which is why the condition can cluster in families and often begins around puberty.
Risk factors and related conditions
Several factors raise the risk of developing hidradenitis suppurativa or of having more severe disease:
- A family history of the condition
- Smoking, which is strongly linked to the disease
- Excess weight, which is associated with more severe symptoms
- Hormonal changes, including those after puberty and around the menstrual cycle
Hidradenitis suppurativa also travels with other health conditions more often than chance would predict, including acne, arthritis, diabetes, metabolic syndrome, and inflammatory bowel disease. This is one reason doctors sometimes order blood tests: not to diagnose the skin disease itself, but to gauge overall inflammation and screen for related problems.
How hidradenitis suppurativa is diagnosed and the blood markers involved
There is no single blood test that confirms hidradenitis suppurativa. A dermatologist usually diagnoses it from your history and a physical examination, looking for the tell-tale pattern of recurring lumps, abscesses, and tunnels in typical locations. Even so, blood work often accompanies the assessment, and understanding those numbers can make your results feel less intimidating.
Because this is an inflammatory condition, several routine markers can rise when the disease is active. To make sense of these numbers, you can consult our guide to C-reactive protein blood test results. You can also review our guide to the erythrocyte sedimentation rate, since these two markers often move together when inflammation is present anywhere in the body.
A standard blood count adds more context. To see how the cells in your blood fit together, explore our overview of the complete blood count. Because neutrophils are the immune cells most involved in these skin lesions, it also helps to read our guide to neutrophil blood results, and for the wider white-cell picture you can see our explainer on white blood cell results.
Doctors also watch patterns that combine these numbers, such as the neutrophil-to-lymphocyte ratio, a simple calculation from your blood count that tends to rise with inflammation. Some of this inflammation stays low and steady rather than flaring; to recognize that pattern, review our explainer on hidden signs of chronic low-grade inflammation. Ferritin, an iron-storage protein, can also climb during inflammation, so a high value does not always mean high iron; for that reason it helps to check our guide to ferritin blood levels.
If joint pain accompanies your skin symptoms, your doctor may add autoimmune tests, and you can preview one by reading our overview of rheumatoid factor lab results. None of these markers is specific to hidradenitis suppurativa on its own; they are pieces of a bigger picture that your clinician reads together with your symptoms. To turn those numbers into plain language before your appointment, try our AI-powered blood test interpretation service.
How hidradenitis suppurativa is treated
There is no cure for hidradenitis suppurativa yet, but a growing range of treatments can control symptoms, reduce flares, and prevent scarring. The right plan depends on the stage and severity, and it often combines several approaches. Early treatment matters, because it can slow the disease before permanent tunnels and scars form.
| Approach | Examples | Typically used for |
|---|---|---|
| Skin care and lifestyle | Antiseptic washes, loose clothing, quitting smoking, weight management | All stages, as a foundation |
| Topical and injected medicines | Topical antibiotics, steroid injections into lumps | Mild, localized disease |
| Oral medicines | Antibiotic courses, hormonal therapy, metformin | Mild to moderate disease |
| Biologic therapy | Adalimumab, secukinumab, and other immune-targeted drugs | Moderate to severe disease |
| Procedures and surgery | Drainage, deroofing, laser, wide local excision | Severe or persistent lesions |
Antibiotics in hidradenitis suppurativa are used mainly to calm inflammation rather than to treat an infection. Biologic therapy, which uses laboratory-made antibodies that block specific immune signals, has changed care for moderate-to-severe disease, and more options are arriving, as the research section below explains. Pain relief, careful wound care, and mental-health support are also important parts of a complete plan.
When to see a doctor about hidradenitis suppurativa
Early diagnosis is the single most useful step, so it is worth seeing a dermatologist sooner rather than later. Consider booking an appointment if you notice:
- Painful lumps that keep coming back in the same area
- Sores that drain pus or have an odor
- Lesions in more than one location, or on both sides of the body
- Bumps that do not settle within a couple of weeks
- Scarring, or lumps that limit how you move
Seek prompt care if a lump becomes very red, hot, and painful along with a fever, which can signal a secondary infection. Because hidradenitis suppurativa is linked with conditions such as diabetes and heart disease, your doctor may also check related health markers over time. The condition is rarely dangerous, but the earlier it is managed, the better the long-term outlook.
Latest scientific advances in hidradenitis suppurativa
Research into hidradenitis suppurativa has accelerated, especially around biologic drugs and the blood markers that track inflammation. Here are a few recent findings, translated into plain language. None of them replaces your dermatologist’s advice, and results always need to be read in context.
Blood inflammation markers mirror disease activity
According to a 2025 systematic review and meta-analysis indexed in PubMed, markers such as C-reactive protein, the erythrocyte sedimentation rate, and the neutrophil-to-lymphocyte ratio are, on average, higher in people with hidradenitis suppurativa than in those without it, and several rise further as the disease becomes more severe (DOI).
What this means for you: if your inflammation markers are raised, they may reflect the activity of the condition rather than a separate illness, though they cannot diagnose it on their own.
In plain terms: the neutrophil-to-lymphocyte ratio is simply your neutrophil count divided by your lymphocyte count, two numbers already printed on a standard blood count.
A newer biologic joins the treatment options
Two large, identical clinical trials called SUNSHINE and SUNRISE, published in The Lancet in 2023, tested a biologic named secukinumab. Around 42 to 45 in every 100 people with moderate-to-severe hidradenitis suppurativa reached a meaningful improvement at 16 weeks, and the benefit lasted up to a year (DOI).
What this means for you: there is now more than one approved biologic, so if one does not help, another may be worth discussing.
In plain terms: a biologic is a laboratory-made antibody that blocks a specific inflammatory signal, in this case a messenger called interleukin-17.
More treatments are on the way
A 2025 review in the Annual Review of Medicine summarized that the two currently approved biologics help roughly half of the people who take them, and that several new drugs aimed at other immune targets are moving through clinical trials (DOI).
What this means for you: the range of options is widening, which is encouraging if current treatments have not fully worked.
Treatment can lower the numbers on your labs
A 2025 study in the European Journal of Dermatology followed people taking the biologic adalimumab and found that, after 16 weeks, blood inflammation markers including C-reactive protein and the neutrophil-to-lymphocyte ratio fell alongside clinical improvement (DOI).
What this means for you: tracking these markers over time may help show whether a treatment is working, a use that researchers are still refining.
Glossary of key terms
| Term | Definition |
|---|---|
| Hidradenitis suppurativa | A chronic inflammatory skin disease causing recurring lumps, abscesses, and tunnels in skin folds. |
| Acne inversa | Another name for hidradenitis suppurativa; despite the name, it is not ordinary acne. |
| Abscess | A painful, pus-filled pocket that can form under the skin. |
| Sinus tract | A tunnel under the skin that connects lesions and drains fluid. |
| Autoinflammatory | Driven by the body’s own immune system rather than an outside infection. |
| Hurley stage | A system that grades severity from I to III based on scarring and tunneling. |
| Biologic | A laboratory-made antibody that blocks a specific immune signal. |
| C-reactive protein | A protein made by the liver that rises with inflammation in the body. |
| Neutrophil-to-lymphocyte ratio | A value from a blood count used as a general marker of inflammation. |
| Erythrocyte sedimentation rate | A blood test that reflects general inflammation by how fast red cells settle. |
Frequently asked questions
How do you pronounce hidradenitis suppurativa?
It is pronounced hi-drad-uh-NIE-tis sup-yoo-ruh-TIE-vuh. The name comes from older medical terms, but you may also hear the condition called acne inversa or simply HS. However you say it, the most important thing is recognizing the pattern of recurring, painful lumps in skin folds, so you can get an accurate diagnosis from a dermatologist.
Can hidradenitis suppurativa go away on its own?
Hidradenitis suppurativa is a chronic condition, so it tends to come and go in flares rather than disappear completely. Some people have long quiet periods, and early, consistent treatment can greatly reduce flares and prevent scarring. There is no cure yet, but many people control the condition well, and for some, losing excess weight or quitting smoking can lessen how often symptoms return.
Can hidradenitis suppurativa appear on the face?
It is uncommon on the face. Hidradenitis suppurativa usually develops where skin rubs together and sweat glands are dense, such as the armpits, groin, inner thighs, buttocks, and under the breasts. Facial breakouts are far more often ordinary acne. If you are unsure what is causing lumps anywhere on your body, a dermatologist can tell these conditions apart and suggest the right treatment.
How do I know if I have hidradenitis suppurativa?
The strongest clue is a pattern: painful lumps or boils that keep returning in the same skin folds, often on both sides of the body, and that are slow to heal. Blackhead-like spots and draining tunnels are other signs. Only a clinician can confirm it, usually from your history and an examination, so it is worth seeing a dermatologist if these signs sound familiar.
Is hidradenitis suppurativa dangerous?
For most people, hidradenitis suppurativa is not life-threatening. It can be painful and affect daily life and mood, and rarely a lump can develop a secondary infection that needs prompt care. Over many years, severe untreated disease carries a small risk of other complications. The reassuring message is that early treatment and regular follow-up greatly improve the outlook.
Can hidradenitis suppurativa be prevented?
There is no guaranteed way to prevent hidradenitis suppurativa, especially because family history and genetics play a role. However, some steps may lower how often or how severely flares occur: not smoking, staying at a healthy weight, wearing loose clothing to reduce friction, and using gentle skin care. If you already have the condition, following your treatment plan is the best way to keep flares in check.
Sources
- Mayo Clinic — Hidradenitis suppurativa: Symptoms and causes, 2025 — mayoclinic.org
- Cleveland Clinic — Hidradenitis Suppurativa (Acne Inversa): Symptoms and Treatments, 2022 — my.clevelandclinic.org
- American Academy of Dermatology — Hidradenitis suppurativa: Overview, 2026 — aad.org
- Li Y-H, Chuang S-H, Yang H-J — Systematic review and meta-analysis of peripheral blood inflammatory markers in hidradenitis suppurativa — The Journal of Dermatology, 2025 — doi.org/10.1111/1346-8138.17661
- Kimball AB, Jemec GBE, Alavi A, et al. — Secukinumab in moderate-to-severe hidradenitis suppurativa (SUNSHINE and SUNRISE) — The Lancet, 2023 — doi.org/10.1016/S0140-6736(23)00022-3
- McCarthy S — Hidradenitis Suppurativa — Annual Review of Medicine, 2025 — doi.org/10.1146/annurev-med-051223-031234
- Arce C, Lobo I, Rodrigues A, et al. — Adalimumab for the treatment of hidradenitis suppurativa: clinical response and impact on inflammatory markers — European Journal of Dermatology, 2025 — doi.org/10.1684/ejd.2025.4903
Further reading
- Antinuclear antibody (ANA) test results
- Anti-CCP blood test results
- Procalcitonin test results
- Gut health and inflammatory skin conditions
- A patient guide to understanding lab results
Understand your lab results with BloodSense
Get your results interpreted in minutes
If you are living with hidradenitis suppurativa, your lab report can feel like a wall of numbers. BloodSense turns markers such as C-reactive protein, the erythrocyte sedimentation rate, and a complete blood count into clear, plain-language context about the inflammation behind your symptoms. It helps you understand your results and prepare sharper questions for your visit. It does not diagnose hidradenitis suppurativa or any condition, and it does not replace your doctor, who remains the only person qualified to interpret your health and decide on care.
