Blog
Ingrown hairs or hidradenitis suppurativa? How to tell recurring bumps apart
Ingrown hair or hidradenitis suppurativa? Compare depth, pain and lumps that keep returning side by side, and learn when a bump needs a dermatologist visit.
Key takeaways
Ingrown hairs and hidradenitis suppurativa (HS) can look similar, but they have different causes. Ingrown hairs typically appear as small bumps, often after shaving or waxing, while HS causes deeper, more painful lumps that may last for weeks.
Recurring lumps are one of the biggest clues that it could be HS. Unlike a typical ingrown hair, HS often causes lumps that repeatedly develop in the same areas, particularly the armpits, groin, inner thighs, and buttocks.
Shaving can irritate both conditions, but it doesn't cause HS. If bumps continue to return even when you're not removing hair, there may be an underlying skin condition.
See a dermatologist if bumps are persistent, painful, or keep coming back. Early diagnosis and treatment can help manage HS and prevent complications such as scarring and tunnels beneath the skin. Seek prompt care if you also develop fever or signs of a spreading infection.
Ingrown hairs and hidradenitis suppurativa (HS) can look remarkably similar, especially in their early stages. Both can cause painful bumps around hair follicles, often in areas like the armpits, groin, and inner thighs.
The main difference is how the bumps develop and behave over time. Ingrown hairs typically occur when hair grows back into the skin, often after shaving or waxing. HS is a chronic inflammatory condition that causes deeper, painful lumps that may drain, scar, and repeatedly return to the same areas.
Understanding these differences can help you recognize when a recurring bump may be more than an ingrown hair and when it's time to see a dermatologist.
This guide walks through how the two differ, where boils and shaving fit in, and when to see a specialist. For a fuller picture of the condition itself, you can read our HS condition guide.
Why early HS can look like an ingrown hair
Early HS symptoms can be difficult to distinguish from ordinary ingrown hairs. Both conditions involve hair follicles and may cause tender, inflamed bumps in areas commonly affected by shaving or friction.
According to the HS Foundation, early HS lumps are frequently mistaken for pimples or ingrown hairs. These lumps may gradually grow larger, persist for weeks or months, and return to the same locations.
The American Academy of Dermatology (AAD) also notes that early HS can resemble a deep pimple, acne cyst, or boil.
Where bumps appear can provide another clue. HS most commonly develops in areas where skin rubs together, including the armpits, groin, inner thighs, buttocks, and beneath the breasts.
In men, recurring lumps in the groin and buttocks may be particularly easy to mistake for ingrown hairs or boils. Learn more about HS symptoms in men and when they may indicate an underlying condition.
Hidradenitis suppurativa vs ingrown hair: how they compare
Although ingrown hairs and HS can look alike, several characteristics can help distinguish them.
An ingrown hair develops when a hair grows back into the skin rather than emerging normally. This often happens after shaving, tweezing, or waxing, particularly in people with tightly curled hair. According to Mayo Clinic, most ingrown hairs resolve without treatment.
HS, on the other hand, involves chronic inflammation around hair follicles. Its lumps tend to develop deeper beneath the skin, persist longer, and recur in the same areas.
Feature | Ingrown hair | HS |
|---|---|---|
Depth | Small bump where hair was removed, sometimes with a looped hair visible | Deep, painful lump under the skin |
Pain level | Itching, burning or stinging; may hurt | Often painful and tender to the touch |
How long it lasts | Most get better without treatment | Can last for weeks or months |
Whether it drains | May be filled with pus | Can open and drain pus or blood |
Whether it returns in the same spot | New bumps can appear where you keep removing hair | Often returns to the same area, sometimes the exact same spot |
Tunnels or scarring | Can leave darker spots or, in some people, raised scars | Repeated healing and reopening can form tunnels under the skin and scars |
Link to shaving | Follows shaving, tweezing or waxing | Exact cause unknown |
Where it appears | Anywhere you shave, tweeze or wax | Skin folds such as the armpits, groin, inner thighs, buttocks and under the breasts |
The most important distinction is often the overall pattern rather than the appearance of a single bump.
A bump that develops after shaving and gradually resolves may be an ingrown hair. Repeatedly developing deep, painful lumps in the same areas, particularly when accompanied by drainage or scarring, can suggest HS.
Skin color can also affect how these bumps appear. On darker skin, HS inflammation may look purple, brown, or gray rather than red. Learn more about recognizing HS on Black and brown skin.
Is it a boil or an ingrown hair?
A boil is a pus-filled infection around a hair follicle or oil gland, usually caused by staph bacteria. It usually forms as a red, painful lump as pus collects under the skin. An infected ingrown hair can look like a small boil, which adds to the confusion.
Boils usually follow a predictable course. The AAD guide to treating boils notes that most boils heal on their own within 1 to 3 weeks. It also says that if boil-like lumps occur often and repeatedly, you could have HS.
Avoid squeezing or piercing a boil. If a boil is large or deep, a doctor can drain it, as MedlinePlus on boils explains.
When boil-like lumps keep returning, the more useful next step is a dermatologist. Our guide to boils that keep coming back explains what that pattern can mean.
Why shaving can make armpit bumps worse
A razor cuts each hair to a sharp tip. That tip can curl back and pierce the skin, which creates an ingrown hair.
MedlinePlus, from the National Library of Medicine, explains how shaving inflames follicles. This condition, folliculitis, starts when follicles are damaged or blocked, for example by shaving or rubbing clothing. Most of the time, the damaged follicles become infected with staph bacteria.
Skin that already has HS reacts in its own way. Small nicks and friction can aggravate the inflammation, so armpit lumps may seem worse after you shave.
Researchers are still working out what causes HS. It begins in hair follicles that become clogged, and AAD on what causes HS lists family history, smoking, excess weight and hormones as possible factors. Shaving isn't among the causes experts name, but irritation can make existing HS worse.
The pattern after shaving offers a useful clue. If bumps settle once you give the area a break from the razor, irritation is the more likely cause. If lumps return to the same spots however you groom, see a dermatologist.
For people who have HS, hair removal calls for some care. The AAD self-care tips for HS say dermatologists advise taking care when shaving and, in general, never waxing. Our guide to gentler hair removal options covers trimming, laser hair removal and safer shaving.
Signs your bumps may be HS
These signs point toward HS rather than a routine shaving bump:
Lumps that feel deep and painful rather than small and itchy
Lumps that last weeks rather than days
Lumps that return to the same spot
Lumps that open and drain
Lumps that leave tunnels under the skin or scars that build up
Lumps in more than one skin fold, such as the armpits, groin, buttocks or under the breasts
Lumps that keep coming back after antibiotics or drainage
Lumps similar to ones a parent, sibling or other relative has had
One sign alone says little, but several together are a good reason to see a dermatologist. A health care professional, often a dermatologist, makes the diagnosis. This list is a way to describe what you notice.
When to see a dermatologist
See a dermatologist when bumps don't follow the expected course or keep returning in the same spot. You don't need to know whether it's HS before you book. Simply describe what you're experiencing.
Early recognition matters. A clinical review of HS from StatPearls reports that diagnosis is often delayed by an average of 7 years because HS resembles other conditions. Dermatologists have specialized training that gives them deep expertise in diagnosing and treating conditions of the skin, hair and nails.
What to track before your visit
Your history matters as much as the exam. A lump may be quiet on the day you're seen, so a record of past flares helps your dermatologist see the full pattern. Bring what you can:
Dated photos of each flare
A simple log of where and when bumps appear and clear
A list of every area affected
Your hair removal routine and whether bumps tend to follow it
Treatments you've tried, such as antibiotics or drainage, and how each worked
Any family history of similar lumps
You can open the visit in your own words. For example: "I keep getting painful lumps in my armpits. They show up in the same places, and they come back after antibiotics."
Dermatologists examine the armpits, groin and buttocks routinely, so you can show every affected area.
What a dermatologist looks for
There is no specific test for HS, as the MedlinePlus HS health topic notes. A dermatologist looks at where the lumps are, when they started and how they behave over time. Your photos and notes fill in the parts of that story the exam can't show.
When a lump is draining, a swab can show whether an infection is also present. HS itself is not an infection. You can read more about how HS differs from infection and how a dermatologist sorts the two out.
If it is HS, treatment is matched to how far it has progressed, and the AAD's guide to how dermatologists treat HS lists the options. These include medicines applied to the skin, antibiotic pills, biologics (injected medicines that target specific immune signals) and in-office procedures. Early diagnosis and treatment can reduce flare-ups and help keep HS from getting worse.
Seeing an HS specialist at Tono
Tono's HS specialty program covers diagnosis, biologic management, treatment escalation, long-term follow-up and coordination of procedural care. Every visit is led by a specialist. Visits can be by video or in person.
Some care needs to happen in person. Cultures, drainage, biopsies and procedures take place at Tono Brooklyn or are coordinated closer to home. Your dermatologist will explain which parts of your care fit each setting.
Tono's co-founder and Chief Medical Officer is Dr. Mondana Ghias, a board-certified dermatologist and recognized authority in HS who has authored more than two dozen peer-reviewed publications, including award-recognized research advancing the treatment of the disease. Tono has cared for more than 20,000 patients across a 33-state clinical footprint.
Getting started is straightforward. Appointments are often available within days, and most insurance is accepted. No referral is needed for most plans, though some HMO plans require one.
When to get care right away
Contact a doctor promptly if a lump comes with a fever or red streaks spreading from the sore. The same applies to other signs of infection, such as worsening pain or swelling. These signs need prompt attention whether or not the cause is HS.
Frequently asked questions
Do ingrown hairs go away on their own?
Yes, most ingrown hairs get better without treatment. If one doesn't clear up, a dermatologist can suggest options such as medicine or laser hair removal, as Mayo Clinic ingrown hair treatment describes.
Can an ingrown hair turn into HS?
Ingrown hairs and HS are separate conditions with different causes. An ingrown hair is a hair growing back into the skin, while HS is an inflammatory condition that starts in clogged hair follicles. Early HS lumps can look like ingrown hairs, which is why the pattern over time matters.
Is HS contagious?
No. HS is not contagious and cannot spread to other people.
Can HS be mistaken for herpes or an STI?
Yes. HS can look like other skin conditions, including boils or herpes, but it is not a sexually transmitted infection. A dermatologist can examine the area and order tests if needed.
What kind of doctor should I see for recurring bumps?
See a dermatologist, ideally one experienced in HS. A dermatologist can follow your lumps over time and adjust care as the pattern becomes clear.
One bump on its own says little. Bumps that return to the same spot form a pattern worth naming, and naming it opens the door to treatment designed for HS.
Schedule an in-person or virtual appointment with a Tono Health specialist.
