Painful Lumps in the Armpits or Groin (Hidradenitis Suppurativa)

There's a specific and common story behind this condition: someone gets a painful lump in their armpit or groin. It's treated as a boil, drained, and clears. Months later, another one. Then another, in the same place. Antibiotics, repeatedly. Years of assuming it's bad luck, bad hygiene, or stubborn acne.

That pattern has a name — hidradenitis suppurativa (HS) — and it takes an average of seven years to get diagnosed (StatPearls). If it sounds like you, this is a conversation to have with a dermatologist soon rather than eventually.

What HS is

HS is a chronic inflammatory skin condition that produces painful, deep-seated nodules, abscesses, tunnels under the skin (sinus tracts), and fibrotic scarring. It concentrates in intertriginous areas — where skin touches skin: the armpits, groin, perianal and perineal area, buttocks, inner thighs, and under the breasts (StatPearls).

The AAD describes the first sign as often looking like a deep pimple, an acne cyst, or a boil, typically in an armpit or the groin (AAD). That resemblance is exactly why it gets missed.

It affects roughly 1% to 4% of people, probably more given how often it's misdiagnosed. Women are affected about three times as often as men, and onset is usually between puberty and 40, most commonly in the twenties (StatPearls).

What it is not

Let's be direct, because the misinformation here does real harm:

• It is not caused by poor hygiene, and it is not contagious (StatPearls).
• It is not primarily a bacterial infection. Lesions can become secondarily infected, which is why antibiotics sometimes help temporarily — but treating it as a series of unrelated infections misses the disease.
• It is not ordinary body acne, though the two can look similar early on.
• It is not your fault. Between 33% and 40% of people with HS have a first-degree relative with it.

What raises the risk

Three factors stand out (StatPearls):

• Smoking — strongly associated with both developing HS and with worse disease. Quitting is one of the highest-impact things a person with HS can do.
• Excess weight — through increased skin-on-skin friction and hormonal effects.
• Family history — a genetic predisposition in a large minority of cases.

Note the framing carefully: these influence severity and flares. They don't mean someone caused their own condition, and plenty of people with HS smoke nothing and carry no excess weight.

How doctors stage it

The Hurley staging system guides treatment (StatPearls):

• Stage I — abscesses, single or multiple, without tunnels or scarring
• Stage II — recurrent abscesses with tunnels and scarring, lesions widely separated
• Stage III — diffuse involvement with interconnected tunnels and abscesses across an area

Stage matters because early disease has far more treatment options and less permanent damage. Tunnels and scars, once formed, don't reverse with medication.

Treatment: what's actually available

Diagnosis is clinical — there's no blood test — which is another reason getting in front of a dermatologist matters. Treatment is real and it's layered (StatPearls, AAD):

• Topical and oral antibiotics — used as much for their anti-inflammatory effect as anti-bacterial
• Anti-inflammatory and hormonal medications
• Biologics — adalimumab is the preferred biologic for moderate-to-severe HS, and the treatment landscape here has expanded considerably
• Procedures — laser therapy, deroofing, and surgical excision with grafting for refractory areas
• Lifestyle measures — smoking cessation and weight management, which reduce flare frequency for many people

Self-care that genuinely helps

From the AAD's HS self-care guidance (AAD):

• Wash with an antimicrobial cleanser — benzoyl peroxide or zinc pyrithione washes are commonly recommended.
• Do not scrub. Aggressive scrubbing adds inflammation and worsens HS. Gentle is not weakness here.
• Wear loose clothing. Tight fabric increases the friction that drives flares — the same principle behind chafing.
• Warm compresses for about 10 minutes, several times a day, ease the pain of an active lump.
• Be careful with hair removal. Use antibacterial soap and a protective gel if shaving; avoid waxing. Laser hair removal is an option worth discussing with a dermatologist.
• Stay cool. Heat and sweating drive flares — relevant if you also deal with excessive sweating.
• Choose mild deodorant without alcohol, baking soda, dyes, or fragrance.

The part that isn't about skin

HS carries a heavy load beyond the lesions themselves: pain, drainage, odour, and scarring, with well-documented psychosocial impact. It's associated with depression and anxiety, alongside metabolic syndrome, inflammatory bowel disease, and cardiovascular disease (StatPearls).

If HS is affecting your mood, your relationships, or your willingness to leave the house, that's a legitimate part of the condition and a legitimate thing to raise with your doctor — not an aside.

What else it might be

• Ordinary body acne — comedones and pustules, spread across the back and shoulders rather than concentrated in skin folds
• Folliculitis — shallower, more superficial follicle inflammation
• Ingrown hairs — single bumps tied to shaving, usually resolving on their own
• Boils/furuncles — genuine bacterial infections, which resolve and don't recur in the same spot indefinitely
• Epidermoid cysts — long-standing, often with a central punctum, not cyclically inflamed

The tell for HS is recurrence in the same skin-fold locations, over months to years, with tunnels or scarring developing.

When to see a doctor

Make an appointment — and specifically ask about hidradenitis suppurativa — if:

• You get painful lumps that keep coming back in the armpits, groin, buttocks, inner thighs, or under the breasts
• You've had repeated "boils" drained or repeated antibiotic courses in the same area
• Lumps are draining, tunnelling, or leaving rope-like scars
• Pain is limiting your movement, work, or sleep

Go urgently if you have spreading redness with fever, a rapidly enlarging painful area, or you feel systemically unwell — that can be a serious infection needing immediate care.

HS needs a clinician, not an app — it's diagnosed by examination, it's often deep under the skin, and it's treated with prescription medication. Our skin assessment is informational and fully automated, and it can't diagnose this or any other condition. If the pattern above sounds familiar, the most useful thing you can do today is book a dermatology appointment; catching HS early genuinely changes how it goes.