Hidradenitis Suppurativa: Symptoms, Causes, and How It's Treated

You keep getting painful, swollen lumps in the same tender spots, your armpits, your groin, under your breasts, and you have started to wonder if it is just bad acne or stubborn ingrown hairs. They flare, drain, heal, then come right back. If this sounds familiar, you may be dealing with hidradenitis suppurativa, a chronic skin condition that is far more common, and far more treatable, than most people realize.

Hidradenitis suppurativa (HS) is often misunderstood and frequently diagnosed late. The good news: with the right plan, the painful flares can be calmed and the cycle slowed. Here is what HS actually is, why it happens, and what you can do about it.

What is hidradenitis suppurativa?

Hidradenitis suppurativa, sometimes called acne inversa, is a chronic inflammatory skin condition that causes painful lumps deep under the skin. These lumps form in areas where skin rubs against skin, most often the armpits, groin, inner thighs, buttocks, and under the breasts. Each lesion can look like a pimple, boil, or cyst. It may clear up, then return in the same spot weeks or months later.

HS happens when hair follicles become blocked and inflamed. Over time, the blocked follicles can rupture under the skin, leading to painful abscesses (pus pockets). As the condition progresses without treatment, these can connect under the surface to form tunnels, known as sinus tracts, and leave behind scarring. HS is a long-term condition that cannot be cured, but a dermatologist-guided plan can manage symptoms and reduce how often and how severely you flare.

What are the symptoms and stages?

Early HS can be easy to dismiss as acne, ingrown hairs, or recurrent boils, which is one reason diagnosis is often delayed. The hallmark is painful lumps that keep coming back in the same friction-prone areas.

Common signs of HS include:

• One or more tender, swollen lumps deep under the skin
• Lesions that fill with pus, drain, heal, and then return in the same area
• Most often in the armpits, groin, inner thighs, buttocks, and under the breasts
• Over time, tunnels (sinus tracts) that form under the skin and may leak fluid
• Thick, rope-like scarring in areas that flare repeatedly

What causes HS and who gets it?

HS is driven by blocked, inflamed hair follicles, not by poor hygiene, and it is not contagious. Several factors raise the risk. Obesity contributes through skin-fold friction and chronic systemic inflammation, and cigarette smoking is strongly linked, likely through follicular occlusion and delayed healing. Genetics matter too: about one-third of patients report an affected first-degree relative.

HS most often begins after puberty, in the second-to-third decades of life, most commonly between ages 18 and 29. It is more common than many people assume. A JAMA Dermatology systematic review and meta-regression estimated an overall global prevalence of roughly 1% (about 0.99%), and female sex at birth was the factor most associated with higher prevalence. A 2024 US population-based analysis from the All of Us research program (287,011 participants) found an overall prevalence of 0.58%, peaking at 0.89% among adults aged 18 to 39, with women affected far more than men (0.77% versus 0.28%). That same analysis found a steep socioeconomic gradient: people earning $10,000 or less per year had the highest prevalence at 0.92%, compared with 0.35% among those earning $50,000 or more.

Hidradenitis suppurativa vs. acne and boils

Because HS lesions can look like pimples or boils, it is often confused with both, but there are important differences. Ordinary acne tends to appear on the face, chest, and back, while HS targets skin-fold areas like the armpits and groin. A single boil is usually a one-time bacterial infection that resolves; HS is a chronic, recurring condition that comes back in the same places.

The biggest tell is the pattern. If painful lumps keep returning to the same friction-prone spots, sometimes forming tunnels or leaving scars, that recurring cycle points toward HS rather than isolated acne or a stray boil. This distinction matters, because HS is associated with a diagnostic delay of roughly 3 to 10 years from when symptoms first start, and that delay allows the disease to progress before treatment begins.

How is hidradenitis suppurativa treated?

HS cannot be cured, but it can be managed, and treatment works best when it starts early. A dermatologist creates a plan based on how severe your HS is and how often you flare. Mild cases may be controlled with topical and oral medications, while more advanced disease may need stronger therapies or procedures.

Common approaches a dermatologist may consider include:

• Oral antibiotics to reduce the inflammation and bacteria driving flares
• Topical treatments and antiseptic washes for milder, localized disease
• Biologic medications for moderate-to-severe HS; two are FDA-approved, adalimumab (Humira), a TNF-alpha inhibitor approved in 2015, and secukinumab (Cosentyx), an IL-17A inhibitor approved in 2023 and later expanded to adolescents aged 12 and older
• Procedures, such as draining or surgically removing recurrent lesions and tunnels
• Lifestyle steps that may help, including quitting smoking, reducing friction, and weight management where appropriate

When should you see a doctor?

See a dermatologist or other clinician if you have recurring painful lumps in skin-fold areas, especially if they drain, scar, or keep coming back. Because HS is so often mistaken for acne or boils and diagnosed years late, getting evaluated early can make a real difference in slowing progression and easing pain. You do not need to wait until it is severe.

Seek prompt medical care if a lesion becomes intensely painful, rapidly spreading, or is paired with fever or feeling unwell, which can signal a more serious infection. HS also takes a real emotional and physical toll, so do not hesitate to ask for help, both for your skin and for the day-to-day burden it can carry. A personalized, clinician-guided plan, whether through your dermatologist or a service like Nolla, is the most reliable path to getting flares under control.