If you keep developing painful lumps under your arms, you may think they are spots, boils or shaving irritation. You should know that recurring deep, painful lumps in your armpits can be a common pattern of hidradenitis suppurativa (HS), especially when they keep returning.
You may find that underarm HS causes tenderness, swelling, drainage and, over time, scars or tunnels beneath your skin. You should also know that shaving, exercise, friction, moisture or tight clothing can make your symptoms feel worse, so you and your doctor can look at the overall pattern when deciding whether you need specialist advice.
Why Does HS Commonly Affect the Armpits?
Your armpits are a common area for HS because they contain many hair follicles and are areas where skin can rub together. You should know that HS is linked to inflammation around hair follicles and is not caused by sweat or poor hygiene, although warmth and moisture can make symptoms feel more uncomfortable.
You may notice that HS starts deeper beneath your skin when a hair follicle becomes blocked and inflamed. You and your doctor can also consider how movement and friction affect your symptoms, as underarm HS may make everyday activities more uncomfortable during a flare.
What Does Underarm HS Usually Look Like?
Underarm HS often starts as a deep, painful lump beneath your skin. You may notice redness, swelling, tenderness or a bruised feeling, and the lump can feel firm rather than like a small surface spot.
You should know that one lump that heals and never returns is different from repeated painful lumps in the same armpit. You and your doctor can look at whether your nodules keep returning, joining together, draining or leaving scars.
How Does Underarm HS Feel?
Pain is common with underarm HS because the inflammation develops deeper beneath your skin. You may notice aching, throbbing or pressure, and the pain can become worse when you move your arm or when the skin rubs together.
You should tell your doctor if you repeatedly have pain in the same underarm, especially with lumps or drainage. You may find that the pain feels stronger than the lump looks, so you and your healthcare professional can consider the full pattern rather than the appearance alone.
How Are HS Lumps Different From Ordinary Underarm Boils?
Underarm boils and HS can look similar, so you may mistake repeated HS flares for infections. A boil is usually linked to a bacterial infection, while HS is a recurring inflammatory condition that can cause painful lumps, drainage, scarring and tunnels.
You should ask why your lumps keep returning rather than focusing only on how one lump looks. If you repeatedly develop painful lumps in the same underarm, especially with drainage or scars, you and your doctor can consider whether HS may be involved.
Evidence Note
Hidradenitis suppurativa is diagnosed by recognising a pattern of recurring lesions in typical areas such as the armpits, groin or skin folds. A single episode that looks like a boil does not always indicate HS; doctors consider recurrence, lesion type, location and long term changes such as tunnels or scarring.
Underarm HS vs Boils vs Folliculitis: Key Differences
| Feature | Hidradenitis Suppurativa | Boil | Folliculitis |
| Main problem | Chronic inflammation around hair follicles | Deeper bacterial infection | Inflammation around individual hair follicles |
| Typical appearance | Deep painful lumps, abscesses, drainage, tunnels | Single painful pus filled lump | Small bumps or pustules around hairs |
| Common pattern | Repeated flares in the same areas | Often one off infection | May occur after shaving, irritation or friction |
| Common sites | Armpits, groin, breast folds, buttocks | Can occur anywhere | Any hair bearing area |
| Scarring | Can cause permanent scars | May scar after deeper infection | Usually minimal in superficial cases |
| Tunnels | Can develop | Not typical | Not typical |
Why Can Sweating Make Underarm HS Feel Worse?
Sweating does not cause HS, but you may find that heat and moisture make your underarms more uncomfortable during a flare. Your skin can become softer and rub more against clothing or surrounding skin, which may worsen irritation.
You should not feel that you need to avoid normal activities because of sweating. You can keep your underarms comfortable by changing out of damp clothes and choosing breathable fabrics, and you and your dermatologist can discuss any pattern you notice.
How Does Friction Affect HS Under the Arms?
Friction can make your underarm HS more painful and irritated, especially when your skin is already inflamed. You may notice more discomfort with tight clothing, rough fabrics or activities that involve repeated arm movement.
You can reduce irritation by choosing loose, breathable clothing and avoiding shaving or harsh products over painful or broken skin. You should tell your dermatologist if friction regularly makes your symptoms worse, as this can help them understand how your HS affects you.
Clinical Tip
Take photographs of your underarm during active flares and note possible triggers such as friction, shaving, sweating or clothing changes. This can help your dermatologist understand the pattern, especially if the skin looks calmer during your appointment.
Can Shaving Trigger Underarm HS Flares?
Shaving does not cause HS, but you may find that it irritates skin that is already prone to inflammation. You may notice more discomfort after shaving because repeated hair removal can cause small areas of skin trauma, although a new lump could also be folliculitis or an ingrown hair.
You should focus on the overall pattern rather than timing alone, especially if you keep getting deep underarm lumps, drainage or scars. You can avoid shaving directly over painful lesions, use a clean razor and avoid pressing too firmly, while you and your dermatologist can discuss other hair removal options if shaving regularly worsens your symptoms.
What Are HS Tunnels Under the Armpits?
Tunnels beneath your skin can be a sign of more established HS. You may notice a small opening that keeps draining, a cord like feeling under your skin or several nearby lumps that seem connected.
You should tell your dermatologist if the same underarm area keeps draining or feels connected beneath the skin. You and your doctor can check whether these changes are caused by HS or another condition and decide whether further assessment is needed.
Does Underarm HS Cause Scarring?
Yes, repeated HS flares can cause lasting changes to your skin. You may notice raised, indented, darker or lighter scars, as well as thicker bands of scar tissue where your underarm lumps have repeatedly healed.
You should know that scarring is more than a cosmetic change, as extensive scar tissue can make your armpit feel tight or affect movement. You and your dermatologist should consider HS if you keep developing new scars after repeated painful lumps or “boils”.
How Can Underarm HS Affect Daily Life?
Underarm HS can affect more than your skin because your arms move constantly throughout the day. You may find clothing, exercise, work or hobbies uncomfortable during painful flares, while drainage, odour or visible scars can also affect how you feel.
You should tell your dermatologist how HS affects your everyday life, not just how your skin looks. You and your doctor can consider pain, movement, scarring and the emotional impact when discussing your care.
Research Insight
HS can have a significant effect on quality of life because symptoms such as pain, drainage, odour and scarring may affect physical activity, work and emotional wellbeing. Measuring this impact helps clinicians understand the overall burden of the condition.
Can Underarm HS Spread or Affect Both Armpits?
HS can affect one or both of your armpits, and you may also develop recurring lumps in other areas such as your groin, inner thighs, buttocks or beneath your breasts. You should know that having underarm HS does not mean your condition will definitely spread to other areas.
You and your dermatologist can look at the full pattern of your symptoms, including any recurring lumps elsewhere. You should mention every affected area, even when your underarms are the main problem.
How Is Underarm HS Diagnosed?
You should know that there is no single blood test that confirms HS. Your dermatologist will usually look at the pattern of your symptoms, including where your lumps occur, whether they repeatedly return, and whether they drain or leave scars and tunnels.
You can help by telling your doctor when your lumps started, how often they return and whether you have previously been treated for repeated boils. You may also find it useful to take clear photos during a flare, especially if your skin looks calmer when you attend your appointment.
UK Guidance Note
UK dermatology guidance recommends that HS diagnosis is usually based on the clinical pattern of lesions, their typical locations and recurrence over time. There is no single blood test that confirms HS, although investigations may sometimes be used when another diagnosis or infection needs to be considered.
What Can You Do to Reduce Underarm Irritation?
You can reduce irritation from underarm HS by making small changes that protect your skin and reduce friction. You and your healthcare team can also identify personal triggers that may make your flares feel worse.
- Choose gentle skin care: Use mild cleansing products and avoid harsh scrubbing or strongly fragranced products that may irritate your skin.
- Reduce friction: Wear loose, breathable clothing and avoid tight fabrics that rub against your underarms.
- Manage moisture: Change out of damp clothes after sweating and try to keep the area comfortable during hot weather.
- Avoid irritating active lesions: Do not squeeze or try to drain deep lumps yourself, as this can increase inflammation and skin damage.
You should tell your dermatologist if painful or draining lesions keep returning despite these measures. You and your healthcare team can review your symptoms and discuss treatments that may help control HS.
What Treatments Might Your Dermatologist Discuss?
Treatment depends on how severe your HS is and how it affects you. Your dermatologist may discuss options such as lifestyle adjustments, topical treatments, medicines to reduce inflammation, procedures for persistent tunnels or specialist treatments for more extensive disease.
If your HS is more extensive, your dermatologist may discuss procedures for persistent tunnels or specialist treatments. The approach will depend on your symptoms, the areas affected and how HS is affecting your daily life.
Why Early Assessment Matters for Underarm HS?
Early recognition can help you understand HS before repeated inflammation leads to more tunnels or scarring. You may initially mistake painful underarm lumps for ordinary boils, but repeated flares deserve attention.
You should speak to your doctor if your lumps keep returning, drain repeatedly, leave scars or affect your daily activities. You and your dermatologist can review the pattern and determine whether HS or another skin condition may be responsible.
When Should You See a Dermatologist About Underarm HS?
You should consider specialist advice if you keep developing painful underarm lumps or frequent “boils”. You may need an assessment if you notice deep lumps, repeated drainage, scars or symptoms that affect your exercise, work or clothing.
You and your dermatologist can review how often your flares happen and whether they keep returning in the same areas. You should also take photos during active flares, as your skin may look clearer on the day of your appointment.
What Should You Remember About HS Under the Arms?
Underarm HS is more than painful spots, especially when your lumps keep returning. You may notice deep painful lumps, repeated drainage, tunnels or scarring in the same area, which can help distinguish HS from ordinary boils or folliculitis.
You should know that HS is not caused by poor hygiene, so changing soaps or cleansing routines will not necessarily stop your flares. You and your dermatologist can look at the overall pattern to understand why your symptoms keep returning and what support may help.
Myth vs Fact
| Myth | Fact |
| HS is caused by poor hygiene | HS is not caused by poor hygiene |
| Sweating causes HS | Sweat can worsen discomfort but does not cause HS |
| Shaving causes HS | Shaving may irritate skin but does not cause HS |
| HS is just repeated boils | HS is a chronic inflammatory condition with a different pattern |
| Pus means it is always an infection | HS can drain even though it is not simply an infection |
| Only overweight people develop HS | HS can affect people of different body sizes |
Key Takeaways
- Underarm HS often causes recurring deep painful lumps rather than simple surface spots.
- HS is not caused by poor hygiene, sweating or shaving, although these may worsen discomfort.
- Repeated lumps in the same area, drainage, tunnels or scarring can be important clues.
- Boils and folliculitis can look similar, but the pattern of recurrence helps distinguish HS.
- Early assessment can help your dermatologist understand symptoms and discuss suitable management options.
Frequently Asked Questions
1. What does hidradenitis suppurativa under the arms usually look like?
Underarm HS often causes deep, painful lumps beneath your skin, with redness, swelling, tenderness or drainage. You may notice that the same lumps keep returning and eventually leave scars or tunnels.
2. Why can HS be mistaken for repeated boils?
A boil is usually linked to a bacterial infection, while HS is a recurring inflammatory condition that can cause repeated painful lumps, drainage, scarring and tunnels. You and your doctor can look at whether your lumps keep returning in the same area to help distinguish between them.
3. Can shaving make your underarm HS worse?
Shaving does not cause HS, but it may irritate skin that is already prone to inflammation. You may find it more comfortable to avoid shaving directly over painful lesions and discuss alternative hair removal options with your dermatologist if shaving regularly worsens your symptoms.
4. Can sweating and friction trigger underarm HS flares?
Sweating does not cause HS, but heat and moisture can make your underarms more uncomfortable and increase irritation. You can reduce friction by wearing loose, breathable clothing and changing out of damp clothes when needed.
5. What are HS tunnels under the armpits?
HS tunnels are connected areas beneath your skin that can develop after repeated inflammation. You may notice a small opening that keeps draining, a cord like area under your skin or several nearby lumps that seem connected.
6. Can underarm HS cause permanent scarring?
Yes, repeated HS flares can cause lasting scars, including raised, indented, darker or lighter areas and thicker bands of scar tissue. You should tell your dermatologist if painful lumps repeatedly heal with scars or if scar tissue affects movement.
7. Can HS affect both of your armpits?
Yes, HS can affect one or both armpits, and you may also develop recurring lumps in areas such as the groin, inner thighs, buttocks or beneath the breasts. You and your dermatologist can assess the full pattern rather than focusing only on your underarms.
8. What information helps your dermatologist diagnose HS?
There is no single blood test that confirms HS. You and your dermatologist can assess where your lumps occur, how often they return, whether they drain and whether they leave scars or tunnels.
9. What can you do to reduce irritation from underarm HS?
You can reduce irritation by gently cleansing your skin, avoiding harsh scrubbing and strongly fragranced products, and wearing loose clothing. You should avoid squeezing or trying to drain deep lumps yourself, as this can increase inflammation and damage your skin.
10. Which HS symptoms mean you should seek specialist advice?
You should consider specialist advice if you repeatedly develop painful underarm lumps or ‘boils’, particularly when they drain, scar or affect your daily activities. You and your dermatologist can review how often the flares occur and whether they keep returning in the same areas.
Final Thoughts: Hidradenitis Suppurativa Under the Arms
Hidradenitis suppurativa under the arms can cause recurring painful lumps, drainage, tunnels and scarring that may be mistaken for ordinary boils or shaving irritation. By paying attention to how often your lumps return, where they appear and how they affect your daily life, you and your doctor can recognise when further assessment may be needed.
If you’re looking for a dermatologist in London, you can contact London Dermatology Centre for specialist assessment and advice.
References:
- 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
- Zouboulis, C.C. et al. (2015) ‘European S1 guideline for the treatment of hidradenitis suppurativa/acne inversa’, Journal of the European Academy of Dermatology and Venereology, 29(4), pp. 619–644. Available at: https://pubmed.ncbi.nlm.nih.gov/25640693/
- Saunte, D.M.L. and Jemec, G.B.E. (2017) ‘Hidradenitis suppurativa: advances in diagnosis and treatment’, JAMA, 318(20), pp. 2019–2032. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6239161/
- Alikhan, A. et al. (2009) ‘Hidradenitis suppurativa: a review’, Journal of the American Academy of Dermatology, 60(4), pp. 539–561. Available at: https://www.sciencedirect.com/science/article/pii/S0190962208022010
- Garg, A. et al. (2017) ‘Hidradenitis suppurativa is associated with a higher risk of cardiovascular disease’, Journal of the American Academy of Dermatology, 76(6), pp. 1043–1048. Available at: https://pubmed.ncbi.nlm.nih.gov/28465236/