What are the symptoms of HS?

HS presents as painful deep-seated nodules or abscesses in skin folds like armpits, groin, perianal region and under the breasts. Lesions rupture and drain, heal with scarring and recur. Chronic disease produces sinus tracts connecting multiple abscesses beneath the skin.

Why does HS cause painful armpit sores?

HS preferentially affects the axillae because of high follicle density, apocrine gland concentration and skin-on-skin friction. Follicular occlusion here triggers an exaggerated inflammatory cascade. The warm moist microenvironment facilitates secondary bacterial colonisation and worsens the cycle.

Is hidradenitis suppurativa contagious?

HS is not contagious and not caused by poor hygiene or skin contact. It arises from abnormal immune activation around hair follicles. Secondary colonisation by Staphylococcus aureus and anaerobes occurs within lesions but is a consequence, not the primary cause.

HS is diagnosed clinically based on lesion morphology, intertriginous distribution and recurrence over at least 6 months. No laboratory test is definitive. Diagnosis is typically delayed 7 to 10 years. Biopsy, culture and imaging assess severity or rule out differential diagnoses.

What are the treatment options for hidradenitis suppurativa?

Treatment depends on severity and is topical clindamycin, oral antibiotics (tetracyclines, rifampicin-clindamycin combination), hormonal therapies and biologics. Surgical options include deroofing, wide local excision and laser hair removal.

Can hidradenitis suppurativa be cured?

HS cannot currently be cured but long-term remission is achievable. Biologics and combination therapies have substantially improved outcomes. Early treatment reduces scarring and sinus tract formation. Disease severity fluctuates, with periods of relative quiescence alternating with flares.

What triggers HS flare-ups?

Common HS flare triggers include friction from tight clothing, shaving affected areas, heat and sweating, hormonal changes, stress, smoking and obesity. High glycaemic index diets and dairy consumption are reported triggers, though the evidence base for dietary factors is limited.

When should you see a doctor about HS symptoms?

Consult a dermatologist if recurrent painful nodules in skin folds do not resolve within weeks, recur at the same site or leave scarring. Early diagnosis is critical as delayed assessment is associated with sinus tract formation and reduced treatment response.

Hidradenitis Suppurativa (HS): Causes, Symptoms & Treatment

Medically Reviewed By Dr. Tania Yadav, MD Dermatology - Geetanjali University Udaipur, MBBS - Pt. Bhagwat Dayal Sharma University of Health Sciences Rohtak., Associate Consultant - Dermatology

Updated on: Oct 15, 2026
Published on: Oct 15, 2026

Hidradenitis Suppurativa (HS): Causes, Symptoms & Treatment

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Hidradenitis suppurativa is one of the most underdiagnosed inflammatory skin conditions in dermatology. Patients routinely wait 7 to 10 years between their first lesion and an accurate diagnosis, treated in the interim for recurrent furunculosis, folliculitis or infected sebaceous cysts. It is a disorder of follicular occlusion and immune dysregulation neither an infection nor a hygiene problem that produces a clinically distinctive lesion pattern.

What Is Hidradenitis Suppurativa (HS)

Hidradenitis suppurativa (HS) is a chronic, recurrent inflammatory skin disease arising from the hair follicle unit, not from the apocrine sweat gland as the name implies. It preferentially affects intertriginous skin including the axillae, inguinal folds, perianal and perineal region, inframammary folds and inner thighs. Lesions progress through nodules, abscesses, ruptured sinuses and fibrotic scarring in a recurring cycle.

HS is more prevalent in women. Onset peaks in the second and third decades. HS is substantially underdiagnosed and patients often present to general surgeons with apparent recurrent boils that delay specialist referral.

What Causes Hidradenitis Suppurativa

HS originates from follicular occlusion, the plugging of the hair follicle with keratinous debris. Occlusion leads to dilatation and eventual rupture, releasing follicular contents into the dermis. The immune response (recruiting neutrophils, macrophages and T-lymphocytes) rather than primary bacterial infection drives nodule and abscess formation. Risk factors are:

Genetic susceptibility is well established, with gamma-secretase complex gene mutations (NCSTN, PSENEN, PSEN1) identified in familial HS.
Smoking is the most consistently identified environmental risk factor, acting through follicular occlusion and upregulation of inflammatory pathways.
Obesity amplifies disease through mechanical friction and pro-inflammatory cytokine release.
Perimenstrual flares in women implicate hormonal factors in disease activity.

Symptoms of HS

The earliest lesions in HS are solitary, painful, deeply situated nodules resembling boils. In mild disease they may resolve spontaneously within weeks, only to recur at the same or adjacent sites. In moderate to severe disease nodules coalesce into interconnected abscesses and sinus tracts tunnelling beneath the skin across several centimetres. Drainage of seropurulent material is common and frequently malodorous.

Pain is a defining feature and consistently the dominant complaint. Axillary lesions restrict shoulder movement whereas groin and perianal lesions impair walking and sitting. Chronic pain, interrupted sleep and daily wound dressing affect employment and social participation. Depression and anxiety occur at substantially higher rates than in the general population.

Stages of Hidradenitis Suppurativa

The Hurley staging system classifies HS into three stages based on structural involvement and remains the most widely used clinical tool:

Hurley Stage I: Isolated abscess formation without sinus tracts or scarring and lesions recur but do not interconnect
Hurley Stage II: Recurrent abscesses with sinus tract formation and scarring across one or more separated lesion areas (skin between sinuses is not involved)
Hurley Stage III: Diffuse involvement across one or more anatomical regions with interconnected sinus tracts, multiple draining orifices and extensive scarring (normal skin architecture is largely lost).

How HS Is Diagnosed

HS is a clinical diagnosis as no blood test, imaging, or biopsy is pathognomonic. The three diagnostic criteria are: characteristic lesion type (nodules, abscesses, sinus tracts or scarring), intertriginous distribution and recurrence of at least two episodes within 6 months. Meeting all three is sufficient for diagnosis.

Investigations assess severity or exclude differentials.

Swab culture identifies secondary colonisation and guides antibiotic selection.
Ultrasound including Doppler identifies subclinical sinus tracts and active inflammatory foci beneath apparently quiescent skin, guiding surgical deroofing extent.
MRI provides superior soft-tissue delineation for perianal or deep gluteal disease.

Conditions That Can Look Like Hidradenitis Suppurativa

Several conditions share features with HS and are common sources of diagnostic error in both primary care and secondary settings:

Furunculosis and carbuncles: Staphylococcal infections producing painful abscesses. Unlike HS they respond fully to antibiotics, do not form sinus tracts and lack the recurrent intertriginous distribution of HS.
Pilonidal disease: Natal cleft sinuses can overlap with perianal HS in distribution and both conditions may coexist.
Crohn disease: Perianal Crohn fistulae are the most important differential. Bowel symptoms, skin tags and rectal involvement help differentiate.
Epidermoid or sebaceous cysts: Solitary, mobile, non-recurrent and lacking the multifocal intertriginous pattern of HS.
Sexually transmitted infections including lymphogranuloma venereum: Relevant in the inguinal region (distinguished by serology and exposure history).

Treatment Options for Hidradenitis Suppurativa

HS management is stratified by Hurley stage and disease activity. Treatment options are:

Topical therapy: Clindamycin 1% lotion twice daily is first-line for Hurley Stage I disease, it reduces surface bacterial colonisation and mild inflammation but does not penetrate sinus tracts.
Systemic antibiotics: Doxycycline 100 mg twice daily for moderate disease (as anti-inflammatory and antibacterial treatment). Rifampicin 300 mg combined with clindamycin 300 mg twice daily for 10 to 12 weeks is used for refractory or more extensive disease.
Biologic therapy: Doctors prescribe biologics for moderate-to-severe HS.
Hormonal therapy: Combined oral contraceptives & spironolactone are used in women with documented perimenstrual flares and androgen-sensitive disease.
Surgical intervention: Deroofing of sinus tracts is highly effective with low recurrence rates compared with incision and drainage. Wide local excision is reserved for Hurley Stage III disease. CO2 laser ablation and Nd:YAG laser hair removal reduce follicular density and recurrence in treated areas.

Living With HS - Lifestyle Tips

Modifiable lifestyle factors contribute to disease control along with pharmacological management:

Smoking cessation: The single most impactful lifestyle intervention as cessation reduces flare frequency and improves systemic treatment response
Weight management: A 15% reduction in body weight is associated with meaningful improvement in HS severity scores and modest loss reduces friction, alters adipokine levels and improves inflammatory parameters
Clothing: Loose-fitting breathable fabrics reduce friction and heat accumulation. Tight waistbands and synthetic garments worsen axillary and inguinal disease.
Skin hygiene: Chlorhexidine 4% wash applied to affected areas reduces surface bacterial colonisation without the skin damage caused by aggressive scrubbing.
Hair removal: Shaving in affected areas propagates follicular trauma. Laser hair removal is the preferred option in affected axillary and inguinal skin.
Dietary modification: Low glycaemic index diets and dairy restriction are reported by patients as beneficial.

When to See a Doctor

Dermatologist referral is warranted when:

Painful nodules or boils recur in the axillae, groin, buttocks or perianal region more than twice in 6 months
Lesions leave scarring, pitting, or persistent skin induration after the acute episode resolves
A visible tract or tunnel forms between two lesion sites
Lesions do not respond to a 10 to 14 day antibiotic course or recur immediately after completing it.
The patient reports significant impact on daily activity, sleep or mental health from skin lesions in these areas.

Conclusion

Hidradenitis suppurativa is a chronic condition whose course is largely determined by how quickly it is diagnosed. The misconception that it is a hygiene problem or simple infection delays referral and allows sinus tracts to form. Recognising its intertriginous distribution and associations with Crohn disease and metabolic syndrome should prompt early dermatologic evaluation. Outcomes have improved markedly with biologics and targeted surgery when patients reach a specialist in time.

FAQs

What is hidradenitis suppurativa (HS)?
Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition that affects hair follicles in skin fold areas (like the armpits, groin, buttocks, under the breasts). It causes painful nodules, abscesses and skin tunnels that recur over months and years, leading to scarring.
What causes hidradenitis suppurativa?
HS develops from blocked and ruptured hair follicles not infected sweat glands. This rupture triggers a disproportionate immune response. Risk factors are genetic predisposition, obesity, smoking and hormonal fluctuations.
What are the symptoms of HS?
HS presents as painful deep-seated nodules or abscesses in skin folds like armpits, groin, perianal region and under the breasts. Lesions rupture and drain, heal with scarring and recur. Chronic disease produces sinus tracts connecting multiple abscesses beneath the skin.
Why does HS cause painful armpit sores?
HS preferentially affects the axillae because of high follicle density, apocrine gland concentration and skin-on-skin friction. Follicular occlusion here triggers an exaggerated inflammatory cascade. The warm moist microenvironment facilitates secondary bacterial colonisation and worsens the cycle.
Is hidradenitis suppurativa contagious?
HS is not contagious and not caused by poor hygiene or skin contact. It arises from abnormal immune activation around hair follicles. Secondary colonisation by Staphylococcus aureus and anaerobes occurs within lesions but is a consequence, not the primary cause.
How is HS diagnosed?
HS is diagnosed clinically based on lesion morphology, intertriginous distribution and recurrence over at least 6 months. No laboratory test is definitive. Diagnosis is typically delayed 7 to 10 years. Biopsy, culture and imaging assess severity or rule out differential diagnoses.
What are the treatment options for hidradenitis suppurativa?
Treatment depends on severity and is topical clindamycin, oral antibiotics (tetracyclines, rifampicin-clindamycin combination), hormonal therapies and biologics. Surgical options include deroofing, wide local excision and laser hair removal.
Can hidradenitis suppurativa be cured?
HS cannot currently be cured but long-term remission is achievable. Biologics and combination therapies have substantially improved outcomes. Early treatment reduces scarring and sinus tract formation. Disease severity fluctuates, with periods of relative quiescence alternating with flares.
What triggers HS flare-ups?
Common HS flare triggers include friction from tight clothing, shaving affected areas, heat and sweating, hormonal changes, stress, smoking and obesity. High glycaemic index diets and dairy consumption are reported triggers, though the evidence base for dietary factors is limited.
When should you see a doctor about HS symptoms?
Consult a dermatologist if recurrent painful nodules in skin folds do not resolve within weeks, recur at the same site or leave scarring. Early diagnosis is critical as delayed assessment is associated with sinus tract formation and reduced treatment response.