If you keep getting painful lumps, spots or pus-filled bumps, you may wonder whether they are boils, folliculitis or hidradenitis suppurativa (HS). You should know that early HS can look similar to a boil, so the overall pattern can be more helpful than the appearance of one lump.
HS may repeatedly affect your armpits, groin, inner thighs, buttocks or skin beneath the breasts, sometimes leaving scars or tunnels. If your lumps keep returning, you should tell your doctor so the overall pattern can be assessed.
Why Are HS, Boils and Folliculitis So Easy to Confuse?
All three conditions can cause red or darker bumps, tenderness and pus, so you may not be able to tell them apart from one spot alone. You should know that your overall pattern matters because early HS can resemble a pimple, cyst or boil, while folliculitis usually causes smaller follicle-centred spots.
You and your doctor can look at whether the lumps are deep, superficial, isolated or recurring. If you keep developing deeper lumps in the same areas, tell your clinician because this pattern may help distinguish HS from boils or folliculitis.
What Does Folliculitis Usually Look Like?
Folliculitis usually causes smaller, more superficial bumps around your hair follicles rather than the deeper lumps seen with established HS. You may notice red, pink, brown or darker bumps on your skin, sometimes with a small white or yellow spot in the centre that feels itchy or mildly sore.
You can develop folliculitis anywhere you have hair follicles, including the scalp, beard area, chest, back, buttocks, arms or legs. If your bumps appear after shaving, waxing or plucking, irritation or ingrown hairs may be more likely, although a deeper follicle infection can sometimes develop into a boil.
What Does an Ordinary Boil Look and Feel Like?
A boil is usually deeper and more painful than superficial folliculitis. You may notice a tender or itchy spot on your skin that becomes a firm, painful lump as pus collects, and you may eventually see the centre soften or drain.
A large or deep boil can leave a scar, so you should notice what happens as your lump heals. You and your doctor can also look at how often the lumps return, because repeated painful boils in the same areas may suggest HS.
Where the Lumps Appear Can Be an Important Clue
Location can give you useful clues when HS is being considered. You may notice repeated lumps where your skin rubs together, such as the armpits, groin, inner thighs, buttocks, genital or perineal area and beneath the breasts.
A lump in one of these areas does not automatically mean you have HS. You and your doctor can look at where the lumps appear and how often they return, because repeated deep lumps in characteristic sites may make HS more likely.
Recurrence Is One of the Biggest Differences
You should ask whether your painful lumps keep coming back. You may have a one-off boil that heals completely, although you can also develop recurrent boils that need medical assessment.
You should know that HS usually follows a recurrent or persistent pattern in typical areas. Two or more episodes of typical lesions within six months is a commonly used diagnostic criterion, although your doctor will also consider the type and location of your lesions. Keeping a simple record or photographs of your flare-ups can help show what happens over time.
Clinical Tip
If your lumps come and go before your appointment, take occasional photographs and note the date and location of each flare. A record showing repeated lesions in the same armpit, groin, breast fold or buttock area can be more informative than examining the skin only on a relatively quiet day.
How Deep Are the Lumps?
Depth can give you another useful clue. You may notice that folliculitis causes small, itchy or tender spots on the skin’s surface, while a boil or HS usually feels like a deeper, more painful lump beneath your skin.
Tell your doctor if the lumps consistently feel deep rather than like small surface spots. You and your dermatologist can then consider whether the pattern fits HS, especially if you keep getting deep lumps or scars.
Do Tunnels Under the Skin Suggest HS?
Tunnels are an important clue when your dermatologist is considering established HS. You may feel cord-like areas beneath your skin where repeated lumps have connected, and you may notice pain, pus or scarring in these areas.
Tell your doctor if you notice tunnels around the armpits, groin or other typical HS areas. You and your dermatologist can consider the overall pattern, because drainage alone does not prove HS.
What Does the Scarring Tell You?
Scarring can show you what has happened even after your painful lumps have settled. You may have one scar after a deep boil, while superficial folliculitis usually heals without scarring.
Notice whether your skin has several thick, indented or rope-like scars where lumps keep returning. You and your dermatologist can assess whether these scars, recurring deep lumps and typical locations fit HS better than isolated boils.
HS vs Boils vs Folliculitis: Key Differences
| Feature | Hidradenitis Suppurativa | Boil / Furuncle | Folliculitis |
| Typical lesion | Deep nodules or abscesses | Deep painful infected lump | Small follicle-centred papules or pustules |
| Common locations | Armpits, groin, breast folds, buttocks, genital/perineal areas | Can occur widely, including face, neck, back, thighs and buttocks | Any hair-bearing area |
| Recurrence | Characteristically recurrent or persistent | Often isolated, although recurrent boils can occur | May recur if the trigger persists |
| Tunnels | Can develop | Not typical of an ordinary isolated boil | Not typical of superficial folliculitis |
| Scarring | Can become extensive or rope-like | A deep boil may leave a scar | Superficial disease usually heals without scarring |
| Infection | HS itself is inflammatory, not primarily infectious | Usually bacterial | May be bacterial or non-infectious |
| Blackhead-like lesions | Paired/open comedones can occur | Not typical | Not usually a defining feature |
| Main diagnostic clue | Combination of lesion type, typical site and recurrence | Isolated/deep infection pattern | Follicle-centred superficial pattern |
Does Drainage or Smell Help Distinguish the Conditions?
You may notice pus with both ordinary boils and HS, so drainage alone cannot tell you which condition is present. Look at what happens afterwards, including whether your lumps keep returning, continue draining or leave scars and tunnels.
Tell your doctor if you repeatedly notice pus, bloodstained fluid or a strong odour from the same area. You and your dermatologist can assess the overall pattern, because HS is not caused by poor hygiene even though secondary infection can occur.
UK Guidance Note
British Association of Dermatologists information describes HS as a chronic, recurrent inflammatory condition and makes clear that poor hygiene does not cause it. Bacteria may sometimes contribute to inflammation or secondary infection, but repeated boil-like lesions, tunnels and scarring should prompt assessment for HS rather than being treated repeatedly as isolated infections.
Are Blackheads a Clue to Hidradenitis Suppurativa?
You may notice blackhead-like spots with HS, particularly in areas where your lumps and scars keep returning. You should know that blackheads alone do not mean you have HS, as acne and other follicular conditions can also cause them.
You and your dermatologist can look for paired blackheads alongside recurring deep lumps, tunnels and scarring in the armpits or groin. If you mainly have small spots around your hair follicles without these deeper changes, folliculitis may be more likely.
Does Shaving Suggest Folliculitis Rather Than HS?
Bumps that appear soon after shaving, waxing or plucking may come from irritated hair follicles rather than HS. You can note when the bumps appear and whether your symptoms settle when you stop hair removal, which can help your dermatologist judge the pattern.
- Timing after hair removal: Small bumps that appear soon after shaving or waxing may suggest follicular irritation.
- Type of bumps: Folliculitis usually causes smaller, more superficial spots around hair follicles.
- Improvement after stopping: If the bumps settle when you stop hair removal, irritation may be more likely.
- Deeper recurring lumps: Lumps that continue to return independently of shaving may need assessment for HS.
You should avoid shaving over actively inflamed skin because this can increase irritation. If your painful or deeper lumps keep returning independently of hair removal, your dermatologist can assess the wider pattern.
Does Bacterial Infection Mean It Cannot Be HS?
HS is not primarily caused by infection, unlike many boils and cases of bacterial folliculitis. You may still develop a secondary infection in HS-affected skin, so if your swab is positive, you should know that HS is not automatically excluded.
Tell your doctor if the lumps you call boils keep returning or do not behave like occasional infections. You and your dermatologist can then look at the wider pattern to see whether HS may be involved.
Evidence Note
HS is primarily an inflammatory disorder of the hair follicle rather than a recurring bacterial infection. Bacteria may be present when damaged skin becomes secondarily infected, which is why swab results need to be interpreted alongside the long-term pattern of lesions rather than in isolation.
Can Recurrent Boils Occur Without Hidradenitis Suppurativa?
Yes, having several boils does not automatically mean you have HS. You may develop recurrent bacterial boils that appear on different parts of your body, and certain health conditions can make you more prone to them.
Tell your doctor if the lumps repeatedly affect the groin or armpits or leave increasing scars. You and your dermatologist can then check whether your pattern fits recurrent boils or whether tunnels and repeated deep lumps suggest HS.
Do Pain, Itching or Fever Help Tell Them Apart?
You may notice itching or mild soreness with folliculitis, while a boil or HS lump can become much more painful. You should know that fever, chills or feeling generally unwell are more concerning for infection, so tell your doctor if these symptoms occur.
Tell your doctor about spreading redness, hot or swollen skin, fever or worsening pain. You and your dermatologist can then assess whether a bacterial infection needs treatment, whether or not HS is also present.
How Does a Dermatologist Tell the Difference?
HS is usually diagnosed clinically based on how your lesions look, where they appear and whether they keep returning. Your dermatologist may ask about your symptoms, drainage and how your skin has changed over time while checking for deep lumps, tunnels, scars and comedones.
You should know that no single blood test or swab confirms HS. If you take photographs of previous flare-ups, your dermatologist can use them to assess recurrence; a swab may be used for suspected infection and ultrasound may assess deeper tunnels.
Research Insight
Specialist ultrasound can reveal HS changes beneath the skin that are not obvious during surface examination. In a multicentre study of 143 people with HS, ultrasound changed the assessed severity in a substantial proportion of patients and detected deeper disease that altered treatment planning. Ultrasound is therefore a useful specialist adjunct in selected cases, although HS diagnosis remains primarily based on the clinical pattern.
When Should Recurrent ‘Boils’ Be Checked for HS?
One isolated boil does not usually mean you need an HS assessment. You should speak to your doctor if painful lumps keep returning in the armpits, groin, inner thighs, beneath the breasts or around the buttocks, especially if your skin develops scars or tunnels.
Seek urgent medical advice if your lump causes spreading redness, swelling, severe worsening pain, fever or chills. You and your dermatologist can review the full history to decide whether the pattern fits HS, recurrent boils or another condition, and you should avoid squeezing deep lumps yourself.
Myth vs Fact
| Myth | Fact |
| Every recurrent boil is HS | Recurrent bacterial boils can also occur |
| HS is caused by poor hygiene | HS is a chronic inflammatory condition and is not caused by being unclean |
| Pus proves that a lump is an infection | HS lesions can also drain pus without HS itself being primarily infectious |
| Every groin or armpit lump is HS | Location is only one clue; recurrence and lesion type also matter |
| Shaving-related bumps must be HS | Irritant folliculitis and ingrown hairs commonly follow hair removal |
| Blackheads prove you have HS | Comedones are only useful when considered with other characteristic HS features |
| A positive bacterial swab rules out HS | Secondary infection can occur in skin affected by HS |
| One blood test can diagnose HS | HS is primarily a clinical diagnosis |
Key Takeaways
- Folliculitis usually causes smaller follicle-centred spots, while boils and HS tend to cause deeper, more painful lumps.
- HS becomes more likely when deep lesions recur in typical skin-fold areas and are accompanied by tunnels, drainage or characteristic scarring.
- Two or more episodes of typical lesions within six months can support the recurrence criterion, but diagnosis depends on lesion type, location and history together.
- Pus, smell, a positive swab or shaving-related bumps cannot by themselves confirm or exclude HS; HS is inflammatory and secondary infection can occur.
- Fever, spreading redness, hot or swollen skin or rapidly worsening pain need prompt medical assessment; persistent recurrent lumps should be reviewed by a clinician.
Frequently Asked Questions
1. How can you tell the difference between hidradenitis suppurativa, boils and folliculitis?
These conditions can all cause red or darker bumps, tenderness and pus, so one lesion may not give you the answer. You and your doctor can compare the depth, location, recurrence and scarring to understand which pattern best fits your skin.
2. What does folliculitis usually look like on your skin?
Folliculitis usually causes smaller, superficial bumps around your hair follicles that may be itchy or mildly sore. You may notice these spots on areas such as your scalp, beard area, chest, back, buttocks, arms or legs.
3. How can you recognise a typical boil?
A boil is usually a deeper, painful lump that develops as pus collects beneath your skin. You may notice your lump becoming firm and tender before the centre softens or drains, and you may be left with a scar.
4. Where does hidradenitis suppurativa usually affect your skin?
HS often affects areas where your skin rubs together, including the armpits, groin, inner thighs, buttocks, genital or perineal area and beneath the breasts. You should know that location alone cannot diagnose HS, so your doctor will also consider recurrence and lesion type.
5. Do recurring painful lumps suggest that you may have HS?
Repeated deep lumps in the same typical areas can be an important clue when your doctor is considering HS. You may also notice drainage, scars or tunnels, and you should mention these changes when your skin is assessed.
6. Do tunnels under your skin suggest hidradenitis suppurativa?
Tunnels can be an important sign of established HS, particularly when they occur alongside recurring deep lumps and scarring. You should tell your doctor if you notice cord-like areas, drainage or pain beneath your skin.
7. Can scarring help your doctor identify HS?
Scarring can provide clues about what has happened over time, particularly when several thick, indented or rope-like scars occur where lumps repeatedly return. You and your dermatologist can assess the scars alongside the location and recurrence of your lumps.
8. Can shaving, waxing or plucking cause bumps that look like HS?
Hair removal can irritate your hair follicles and cause small bumps, making folliculitis or ingrown hairs possible explanations. You should know that shaving does not completely rule out HS, so your dermatologist can consider whether deeper lumps continue independently of hair removal.
9. Does bacterial infection mean that your lumps cannot be HS?
No, HS is not primarily caused by an infection, although HS-affected skin can develop a secondary infection. You should tell your doctor if your supposed boils keep returning, as a positive swab does not automatically rule out HS.
10. When should you see a dermatologist about recurring boils or painful lumps?
You should consider a dermatology assessment if painful lumps repeatedly affect your armpits, groin, inner thighs, breast folds or buttocks, especially if they scar or form tunnels. Seek urgent medical advice if you develop spreading redness, severe worsening pain, fever or chills.
Final Thoughts: Hidradenitis Suppurativa vs Boils and Folliculitis
HS, boils and folliculitis can look similar, but the location, depth and recurrence of your lumps can provide useful clues. If you keep developing painful lumps, drainage, scars or tunnels, you should speak to your doctor so the pattern can be assessed.
If you’re looking for a dermatologist in London, you can contact London Dermatology Centre for specialist assessment.
References:
- Nowak-Liduk, A. et al. (2023) ‘Hidradenitis suppurativa: an interdisciplinary problem in dermatology, gynecology, and surgery—pathogenesis, comorbidities, and current treatments’, Life, 13(9), article 1895. Available at: https://www.mdpi.com/2075-1729/13/9/1895
- Martorell, A. et al. (2019) ‘Ultrasound as a diagnostic and management tool in hidradenitis suppurativa patients: a multicentre study’, Journal of the European Academy of Dermatology and Venereology, 33(11), pp. 2137–2142. Available at: https://pubmed.ncbi.nlm.nih.gov/31124183/
- Sayed, C.J., Hsiao, J.L. and Okun, M.M. (2021) ‘Clinical epidemiology and management of hidradenitis suppurativa’, Obstetrics & Gynecology, 137(4), pp. 731–746. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC7984767/
- Reddy, S. et al. (2024) ‘Differentiating hidradenitis suppurativa flare from infection in the emergency department and recommendations for transitioning care to the outpatient setting’, The American Journal of Emergency Medicine, 79, pp. 58–62. Available at: https://www.sciencedirect.com/science/article/pii/S0735675724000639
- Ingram, J.R. et al. (2019) ‘British Association of Dermatologists guidelines for the management of hidradenitis suppurativa (acne inversa) 2018’, British Journal of Dermatology, 180(5), pp. 1009–1017. Available at: https://academic.oup.com/bjd/article/180/5/1009/6732702