Hidradenitis suppurativa (HS) is the condition most commonly behind recurrent, painful, boil-like lumps that keep coming back in the same body areas. It affects skin folds like the armpits, groin, and under the breasts, and while it looks a lot like a regular boil or abscess, it is driven by a misfiring immune system rather than a straightforward bacterial infection. HS sits in a gray zone between autoimmune and autoinflammatory disease, and several other immune-mediated conditions can also produce boil-like skin lesions, making the path to a correct diagnosis surprisingly long for many people.
How HS Produces Boil-Like Lesions
The process starts not with bacteria but with the hair follicle itself. The primary defect is follicular occlusion: the opening of a hair follicle becomes plugged with keratin, the same protein that makes up the outer layer of skin. Once blocked, the follicle swells, eventually ruptures beneath the surface, and spills its contents into the surrounding tissue. The immune system treats this rupture like an invasion, flooding the area with inflammatory cells and creating the painful, red, swollen nodules that look and feel exactly like boils.1PubMed Central. Hidradenitis suppurativa: from pathogenesis to diagnosis and treatment
In early stages, these nodules can be mistaken for garden-variety boils or infected cysts. But unlike a one-off boil caused by a staph infection, HS lesions recur in the same locations. Over time the inflammation can become chronic, producing tunnels beneath the skin (called sinus tracts), draining wounds, and permanent scarring.2PubMed Central. Hidradenitis Suppurativa: Causes, Features, and Current Treatments The disease tends to appear in intertriginous regions, the places where skin rubs against skin, which is why the armpits, inner thighs, groin folds, and under the breasts are classic locations.
Is HS Actually an Autoimmune Disease?
This question has been debated for years, and the honest answer is that HS doesn’t fit neatly into a single immunological category. In classic autoimmune diseases like lupus or rheumatoid arthritis, the immune system produces antibodies that attack specific tissues. HS doesn’t work that way. Instead, the immune overreaction appears to be driven by innate inflammatory pathways, the older, less targeted arm of the immune system. That profile looks more like an autoinflammatory condition, where the body’s danger-sensing mechanisms fire too aggressively without specific antibody targeting.
Research has suggested that HS could be classified as an autoinflammatory keratinization disease, a group of conditions where both abnormal skin-cell behavior and runaway inflammation feed each other. However, whether the inflammation triggers the abnormal keratinization or vice versa remains unresolved.3Frontiers in Immunology. Hidradenitis Suppurativa as a Potential Subtype of Autoinflammatory Keratinization Disease To complicate things further, people with HS have higher rates of classic autoimmune diseases and autoantibodies compared to the general population, raising the possibility that HS itself has an autoimmune component on top of the autoinflammatory one.4PubMed Central. Association of hidradenitis suppurativa with autoimmune disease and autoantibodies
For the person living with HS, the practical takeaway is this: even though dermatologists sometimes hedge on the label, HS is immune-mediated. The treatments that work target the immune system, and the disease behaves like other chronic inflammatory conditions in terms of flares, remissions, and systemic effects on the body.
Other Immune-Mediated Conditions That Cause Boil-Like Lesions
HS is the most common culprit, but it is not the only one. Several other conditions can produce painful skin nodules, abscesses, or draining lesions that get confused with boils.
Crohn’s Disease
Most people think of Crohn’s as a bowel disease, but it can affect skin, particularly around the anus and groin. Perianal Crohn’s disease produces abscesses, fistulas, and draining tracts that look very similar to HS, to the point that clinicians sometimes use the term “Crohn’s-associated hidradenitis suppurativa.”5PubMed Central. Perianal Crohn’s Disease In some patients, the skin involvement shows up before the gut symptoms do, which means that recurrent boil-like lesions near the buttocks or groin sometimes turn out to be an early sign of inflammatory bowel disease. HS and Crohn’s also co-occur at higher-than-expected rates, likely because they share overlapping inflammatory pathways.
Behçet’s Disease
Behçet’s is a systemic vasculitis, an autoimmune condition affecting blood vessels throughout the body. Its hallmark features are painful oral and genital ulcers, but it also produces papulopustular skin lesions that can look a lot like acne or folliculitis, particularly on the legs.6PubMed Central. Mucocutaneous lesions of Behcet’s disease These inflamed bumps can be deep enough to resemble boils. Interestingly, histological examination of these lesions often cannot distinguish them from ordinary acne, which makes the clinical history and other symptoms critical for getting the right diagnosis.7PubMed. Histopathological and clinical evaluation of papulopustular lesions in Behçet’s disease
Pyoderma Gangrenosum
Pyoderma gangrenosum (PG) is a rare inflammatory skin condition that starts as a painful bump or blister and rapidly breaks down into a deep, undermined ulcer with purplish borders. Early PG can look like a boil or abscess, which is dangerous because the instinct to surgically drain it can actually make it worse, a phenomenon called pathergy where trauma to the skin triggers new or worsening lesions.8PubMed Central. Chronic non-healing ulcer reveals pyoderma gangrenosum: A case report PG is associated with inflammatory bowel disease, rheumatoid arthritis, and blood disorders, and it sometimes appears alongside HS in overlap syndromes.
Lupus Panniculitis
A less common variant of lupus called lupus erythematosus profundus (lupus panniculitis) attacks the fatty tissue beneath the skin. It produces firm, painful nodules on the face, shoulders, arms, breasts, and buttocks that can be mistaken for boils or deep cysts. In some cases, these nodules develop draining sinuses, making them look even more like HS.9Clinical Dermatology Review. Lupus Panniculitis Presenting as Multiple Discharging Sinuses Lupus panniculitis can occur on its own or alongside systemic lupus erythematosus.
Overlap Syndromes Worth Knowing About
Some patients develop combinations of these conditions in recognized patterns. PAPA syndrome is a hereditary autoinflammatory condition involving pyogenic arthritis, severe acne, and pyoderma gangrenosum, caused by mutations in the PSTPIP1 gene.10PubMed. Pyoderma gangrenosum, acne, and suppurative hidradenitis (PASH)–a new autoinflammatory syndrome distinct from PAPA syndrome A related condition called PASH syndrome combines pyoderma gangrenosum, acne, and HS without the joint disease. PAPASH syndrome is yet another variant that includes all four: pyogenic arthritis, pyoderma gangrenosum, acne, and HS.11PubMed Central. Pyoderma gangrenosum, acne, and hidradenitis suppurativa (PASH) syndrome with recurrent vasculitis
These syndromes are rare, but they matter because they illustrate something important about HS: it doesn’t always travel alone. Autoimmune conditions like rheumatoid arthritis, ankylosing spondylitis, multiple sclerosis, inflammatory bowel disease, and psoriasis all appear at higher rates in people who have HS.12PubMed Central. Characterization of comorbidity heterogeneity among 13,667 patients with hidradenitis suppurativa If you have HS and develop new symptoms in your joints, gut, or elsewhere, that pattern is worth flagging to your doctor.
Why Getting the Right Diagnosis Takes So Long
One of the most frustrating aspects of HS is how long it takes to get diagnosed. Patients typically see more than three different doctors and receive more than three incorrect diagnoses before someone recognizes it as HS.13PubMed Central. Delayed Diagnosis of Hidradenitis Suppurativa and Its Effect on Patients and Healthcare System The most common misdiagnoses are ordinary boils, folliculitis, infected cysts, and acne. Emergency rooms and urgent care clinics tend to treat each episode in isolation, lancing and draining one abscess at a time without recognizing the recurring pattern.
The diagnostic criteria are actually straightforward: recurrent painful nodules or abscesses in typical locations (armpits, groin, under the breasts, buttocks) with two or more episodes in six months. No lab test or biopsy is needed. The problem is awareness. Many general practitioners and even some surgeons aren’t trained to connect the dots between repeated “boils” in the same areas and an underlying chronic disease. Delays matter because HS tends to progress. Early-stage disease can sometimes be controlled with medications, but advanced disease with tunnels and scarring often requires surgery.
The Role of Skin Bacteria
Because HS lesions look infected and sometimes drain foul-smelling fluid, it is natural to assume bacteria are the root cause. They aren’t, but they play a significant supporting role. The skin microbiome in people with HS is different from that of healthy skin. HS lesions, particularly the tunnels that develop in more advanced disease, harbor a distinct community of bacteria dominated by anaerobes like Porphyromonas, Prevotella, and Fusobacterium, while beneficial skin bacteria like Cutibacterium acnes and Staphylococcus epidermidis are depleted.14PubMed Central. The Microbiome in Hidradenitis Suppurativa Tunnels: A Systematic Review15PubMed Central. Microbiome in Hidradenitis Suppurativa-What We Know and Where We Are Heading
This dysbiosis, or imbalance in the microbial community, contributes to the immune dysfunction seen in HS and may help explain why flares keep happening even when patients are on systemic treatment.16PubMed Central. Hidradenitis Suppurativa: Consequences of Microbiome Dysbiosis on Immune Dysregulation and Disease Severity The disease stage matters too: more advanced HS tunnels contain larger biofilms with more pathogenic bacteria, creating a self-reinforcing cycle in which the microbiome worsens as the disease progresses.14PubMed Central. The Microbiome in Hidradenitis Suppurativa Tunnels: A Systematic Review This is one reason antibiotics provide temporary relief but rarely produce lasting remission on their own: the underlying immune and structural problem keeps recreating conditions that favor the wrong bacteria.
Metabolic Conditions That Travel with HS
HS is more than a skin disease. People with HS face significantly increased risks of metabolic conditions including obesity, insulin resistance, high blood pressure, abnormal cholesterol, and type 2 diabetes.17PubMed Central. Management of Hidradenitis Suppurativa in Patients with Metabolic Comorbidities When researchers adjusted for age, sex, and smoking status, people with HS were roughly two to four times more likely to have metabolic syndrome compared to those without HS, with hospital-based HS patients showing even higher odds than those identified in population studies.18JAMA Dermatology. Association of Metabolic Syndrome and Hidradenitis Suppurativa
Whether obesity drives HS or HS-related inflammation drives metabolic changes (or both) is not fully sorted out. What is clear is that excess body weight worsens HS through mechanical friction in skin folds, which creates micro-injuries that activate the skin’s danger-signaling pathways and allow bacteria from the skin surface to penetrate more easily.19British Journal of Dermatology. Aetiology and pathogenesis of hidradenitis suppurativa This means weight management, while not a cure, can meaningfully reduce flare frequency and severity in many patients. Smoking is the other major modifiable risk factor; nicotine is thought to promote follicular plugging and worsen the inflammatory environment in the skin.2PubMed Central. Hidradenitis Suppurativa: Causes, Features, and Current Treatments
How HS Is Treated Now
The treatment of HS has changed substantially in the past decade thanks to biologic drugs that target specific immune molecules. Adalimumab, which blocks the inflammatory signaling molecule TNF-alpha, was approved for moderate-to-severe HS in 2015. Secukinumab, which targets a different immune pathway (IL-17A), gained approval for HS in 2023.20PubMed. Biology of Interleukin-17 and Novel Therapies for Hidradenitis Suppurativa Bimekizumab, which blocks both IL-17A and IL-17F, has also been approved in some markets, giving patients three biologic options.21PubMed Central. Biologic drugs in hidradenitis suppurativa: what does the GP have to know? A narrative review
The efficacy of existing biologics is moderate rather than dramatic. Many patients improve but few achieve complete clearance, and researchers are actively investigating drugs targeting other pathways, including JAK inhibitors, as next-generation options.22PubMed. Biologics for Hidradenitis suppurativa: evolution of the treatment paradigm For advanced disease where tunnels and scarring have already developed, surgery remains necessary. Options range from limited procedures like deroofing (opening up a tunnel and leaving it to heal from the bottom) to wide excision of entire affected areas. The stage at diagnosis heavily influences what combination of medical and surgical treatment is needed, which is another reason early recognition matters so much.23PubMed Central. Surgical Treatment in Hidradenitis Suppurativa
Diet, Inflammation, and HS
Dietary factors have attracted growing interest as a way to complement medical treatment for HS. The evidence is still emerging, but the direction is consistent. A cross-sectional study found that HS severity correlated positively with dietary glycemic index, intake of refined sugar, junk food, and bakery products, and negatively with adherence to a Mediterranean-style diet and intake of vitamin C and zinc.24PubMed Central. The Impact of Diet on Hidradenitis Suppurativa Severity: A Cross-Sectional Case–Control Study Dairy and high-glycemic foods have been flagged as potential triggers, possibly through mechanisms related to insulin resistance and chronic low-grade inflammation.25PubMed. Evaluating dietary considerations in hidradenitis suppurativa: a critical examination of existing knowledge
None of this means diet alone will control HS, and the evidence base is still largely observational rather than from controlled trials. But given the tight relationship between HS, metabolic syndrome, and systemic inflammation, it’s reasonable to think of dietary changes as one lever among several. Zinc supplementation is worth discussing with a doctor, as it has shown some promise as an adjunct therapy for HS, likely due to its antioxidant and anti-inflammatory properties.
The Psychological Weight of Recurrent Boil-Like Lesions
The toll of HS goes well beyond the physical. Quality-of-life scores in HS patients are on par with the most severe skin diseases studied, with the physical pain, chronic drainage, odor, and scarring driving high rates of depression, anxiety, negative body image, sexual dysfunction, and reduced ability to work.26Clinics in Dermatology. The psychosocial effects of hidradenitis suppurativa Patients with HS report feelings of loneliness and stigmatization, and the suicide risk among people with HS is significantly elevated.27British Journal of Dermatology. Profound consequences of hidradenitis suppurativa: a review
Part of what makes HS so psychologically punishing is the location of the lesions. Armpits, groin, buttocks, and under the breasts are areas people feel deeply private about. Many patients hide their disease from partners, friends, and even doctors out of embarrassment, which feeds diagnostic delay and isolation. If you are dealing with this, connecting with a dermatologist who specializes in HS, rather than cycling through emergency room visits for “boils,” can change the trajectory of both the disease and your mental health.
When It Starts in Childhood or Adolescence
HS is often thought of as an adult disease, but symptoms can begin during puberty or even before. Onset after adrenarche, the stage of development when adrenal hormones begin rising, is typical for pediatric cases, and the disease can progress to severe scarring and tunnel formation in young patients if not caught early.28PubMed. Hidradenitis Suppurativa in the Pediatric and Adolescent Population Clinical studies and treatment guidelines for pediatric HS are sparse, and diagnostic delays are at least as common in younger patients as in adults.29PubMed. Hidradenitis Suppurativa in Pediatric Patients
A teenager with recurrent painful lumps in the armpits or groin is likely to be told they have infected ingrown hairs or acne, and that they’ll grow out of it. That assumption can cost years of uncontrolled disease progression. Pediatricians and parents who notice a pattern of recurring boil-like lesions in skin-fold areas should push for a dermatology referral rather than accepting repeated courses of antibiotics for what keeps being called an infection.