Hidradenitis suppurativa (HS) can get worse over time, but it doesn’t always. A community-based study published in JAMA Dermatology found that about 17% of patients with mild or moderate disease progressed to more severe stages, while 71% actually experienced improvement, with nearly 64% reaching full remission. The trajectory varies widely from person to person, and several factors within your control influence which direction things go.
How HS Progresses
HS starts when hair follicles become blocked. That blockage causes the follicle to swell and eventually rupture beneath the skin, spilling cellular debris into the surrounding tissue. Your immune system responds aggressively, flooding the area with inflammatory signals that recruit waves of immune cells. The result is the painful nodules and abscesses that define early HS.
When this cycle repeats in the same area, the damage accumulates. Repeated inflammation triggers scarring and fibrosis, the body’s attempt to wall off the damage. Over time, these areas can develop sinus tracts (tunnels under the skin connecting separate lumps) that drain blood and pus and heal very slowly, if at all. Once sinus tracts and significant scarring form, they’re permanent structural changes that don’t resolve on their own. This is why catching HS early matters so much: the inflammatory flares are treatable, but the scarring they leave behind is not easily reversed.
What the Stages Look Like
Doctors classify HS severity using the Hurley staging system, which has three levels. Stage I involves single or multiple abscesses without any sinus tracts or scarring. This is the most common starting point, and many people stay here. Stage II means recurrent abscesses have begun forming sinus tracts or scars, with affected areas still separated from each other. Stage III is the most severe: widespread involvement with multiple interconnected tunnels and abscesses across an entire region.
In the JAMA Dermatology study, patients who started with mild disease had the best outlook, with 73.7% achieving full remission. For those with moderate disease at baseline, 60% reached remission. Even among patients who already had severe disease, 46.7% experienced full remission during follow-up. These numbers suggest that while progression is real, it’s not the most common outcome.
Factors That Push HS Toward Worsening
Three modifiable risk factors consistently show up in the research as drivers of more severe HS: smoking, obesity, and delayed diagnosis.
Smoking has the strongest statistical association with HS severity. A large meta-analysis found that smokers were roughly three times more likely to have HS than nonsmokers. Nicotine promotes the kind of follicular plugging that starts the HS cycle, alters the skin’s bacterial environment, and stimulates the release of the same inflammatory molecules that drive HS flares. Smokers consistently have more severe disease than nonsmokers.
Obesity (a BMI of 30 or above) carries about 2.5 times the risk of HS compared to a healthy weight. Higher BMI correlates with more clinically severe disease, likely because fat tissue itself produces inflammatory signals that fuel the cycle. Skin folds also create warm, moist environments where friction and occlusion worsen breakouts. That said, thin people who don’t smoke can still develop severe HS.
Delayed diagnosis is perhaps the most frustrating factor. The average time from first symptoms to an HS diagnosis is about 10 years. During that decade, people often cycle through misdiagnoses (boils, ingrown hairs, skin infections) while the disease quietly progresses. Studies show that the longer the diagnostic delay, the higher the Hurley stage at the time of diagnosis. Every year without appropriate treatment is a year the disease has to cause irreversible damage.
Hormonal Influences on Flares
Hormonal shifts play a clear role in HS activity, particularly for women. Between 43% and 77% of female patients report their HS worsens around their period. About 60% of patients experience worsening after giving birth. These patterns point to the influence of sex hormones on the inflammatory pathways involved in HS. Research has found that HS lesions show increased activity of androgen receptors, and androgen-related genes are upregulated in women with the follicular type of HS.
Thyroid disease also appears connected to severity. One study found that having a thyroid condition was independently associated with more severe HS, with an odds ratio similar to that of active smoking. Insulin resistance, even in people without diabetes, has been linked to disease severity as well.
Whether Early Treatment Changes the Trajectory
Data from the UNITE registry, which tracked 574 HS patients over four years, found that the majority experienced lesion spread, new scarring, or stage progression during that period. Progression was most common in patients who already had severe, long-standing disease. This reinforces a key point: earlier intervention offers more opportunity to change the course.
Biologic therapies, which target the specific inflammatory pathways driving HS, appear to reduce the need for emergency procedures like incision and drainage when used consistently. Registry data suggests that sustained biologic treatment addresses the underlying disease process rather than just managing symptoms, potentially slowing or preventing progression when started at moderate stages. Early initiation of these treatments may improve the overall disease trajectory for people with moderate to severe HS.
Signs Your HS May Be Worsening
The shift from Stage I to Stage II is the critical transition to watch for. Key warning signs include flares that keep returning in the same location, lumps that start appearing in new body areas, and any sign of tunneling beneath the skin (you may feel a cord-like structure connecting two bumps, or notice drainage from an opening that isn’t directly over a nodule). Scarring that leaves thickened, rope-like skin between flares is another sign that the disease is doing cumulative damage even when it feels quiet on the surface.
Long-Term Risks of Uncontrolled Disease
Chronic, long-standing HS carries a small but serious risk of squamous cell carcinoma developing within areas of persistent inflammation and scarring. This complication occurs in roughly 4.6% of chronic HS cases. While uncommon, it tends to be aggressive when it does appear, with a higher potential for early spread than squamous cell carcinomas that arise in other contexts. The risk is tied to the duration and chronicity of the disease, which is one more reason sustained management matters. Any changes in the appearance of long-standing HS lesions, particularly a new growth, rapid enlargement, or bleeding from a previously stable scar, warrant prompt evaluation.