Hidradenitis Suppurativa

Introduction | Aetiology and Risk Factors | Clinical Presentation | Diagnosis | Management and Treatment | Prevention | When to Refer | References

Introduction

Hidradenitis Suppurativa (HS), also known as acne inversa, is a chronic inflammatory skin condition characterised by recurrent, painful nodules, abscesses, and sinus tracts primarily affecting areas of the body where skin folds, such as the armpits, groin, buttocks, and under the breasts. Over time, it can lead to scarring and significant psychosocial impact. The condition often begins after puberty and can persist for many years, with periods of flare-ups and remission.

Aetiology and Risk Factors

The exact cause of Hidradenitis Suppurativa is not fully understood, but it is believed to result from a combination of genetic, environmental, and immune factors:

• Genetic Predisposition: HS often runs in families, indicating a genetic component. Specific genes associated with HS are being studied.
• Follicular Occlusion: The disease is thought to start with occlusion of the hair follicles, leading to inflammation, rupture, and subsequent formation of abscesses and sinus tracts.
• Immune System Dysregulation: There is an abnormal immune response in HS, with increased levels of inflammatory cytokines contributing to the chronicity of the disease.
• Hormonal Factors: HS typically begins after puberty and can be influenced by hormonal changes. It may flare up during the menstrual cycle in women.
• Obesity: Obesity is a significant risk factor, as increased body weight exacerbates friction and occlusion in skin folds, contributing to the development and severity of HS.
• Smoking: Smoking is strongly associated with HS and can worsen the severity of the condition. It is thought to contribute to follicular occlusion and inflammation.
• Mechanical Stress: Friction and sweating in areas where skin rubs together can contribute to the development of HS lesions.

Clinical Presentation

Hidradenitis Suppurativa presents with a range of symptoms, varying in severity:

• Painful Nodules: The primary lesions are deep-seated, inflamed nodules, often painful and tender to touch.
• Abscesses: These nodules can evolve into larger abscesses, which may rupture, releasing pus. The abscesses are recurrent and can coalesce to form extensive areas of inflammation.
• Sinus Tracts: Over time, chronic inflammation can lead to the formation of sinus tracts (tunnels under the skin) that connect the abscesses. These tracts can become persistent and lead to scarring.
• Scarring: The healing of these lesions often results in thick, rope-like scars and fibrosis, leading to disfigurement and restricted movement in severe cases.
• Location: Lesions most commonly occur in the axillae (armpits), groin, perineal area, buttocks, and under the breasts. They can also occur in other intertriginous areas.
• Systemic Symptoms: In severe cases, HS can be associated with systemic symptoms such as fever, malaise, and joint pain.

Diagnosis

The diagnosis of Hidradenitis Suppurativa is primarily clinical, based on the characteristic appearance and distribution of the lesions:

• History: Take a detailed history, including the onset, duration, and pattern of lesions, any associated pain or discharge, and a family history of HS or related conditions.
• Physical Examination: Examine the affected areas for the presence of nodules, abscesses, sinus tracts, and scarring. Note the distribution and severity of lesions.
• Hurley Staging System: HS is often classified using the Hurley staging system:
  • Stage I: Single or multiple abscesses without sinus tracts or scarring.
  • Stage II: Recurrent abscesses with sinus tract formation and scarring. The lesions are widely separated.
  • Stage III: Diffuse or near-diffuse involvement with multiple interconnected sinus tracts and abscesses across an entire area.
• Differential Diagnosis: Consider other conditions that may present similarly, such as folliculitis, carbuncles, pilonidal disease, or acne conglobata. The presence of recurrent lesions in typical areas with sinus tract formation supports the diagnosis of HS.
• Imaging: In cases where deep tissue involvement is suspected, ultrasound or MRI can be used to assess the extent of the disease, particularly in advanced stages.

Management and Treatment

The management of Hidradenitis Suppurativa is tailored to the severity of the disease and involves a combination of lifestyle modifications, medical treatments, and surgical interventions:

1. Lifestyle Modifications

• Smoking Cessation: Strongly encourage patients to stop smoking, as smoking is a major exacerbating factor in HS.
• Weight Management: Advise weight loss in overweight or obese patients to reduce skin friction and improve overall outcomes.
• Skin Care: Recommend gentle skin care, including the use of antiseptic washes (e.g., chlorhexidine) and avoiding tight clothing that may irritate the skin.

2. Medical Treatments

• Topical Treatments:
  • Clindamycin 1%: Topical clindamycin is often the first-line treatment for mild HS (Hurley Stage I). Apply twice daily to affected areas.
• Oral Antibiotics:
  • Tetracyclines: Doxycycline are commonly used for their anti-inflammatory properties in moderate HS (Hurley Stage II).
  • Combination Therapy* specialist treatment: For more severe cases, a combination of clindamycin and rifampicin may be used for a prolonged course (up to 10-12 weeks).
• Hormonal Therapy:
  • Anti-Androgens: In women, hormonal treatments such as oral contraceptives or spironolactone may be beneficial, particularly if HS is hormonally driven.
• Biologics:
  • Adalimumab: This TNF-alpha inhibitor is approved for use in moderate to severe HS (Hurley Stage II and III). It is administered as a subcutaneous injection and can reduce inflammation and lesion count.
• Immunosuppressants:
  • Ciclosporin or Methotrexate: These may be considered in severe, refractory cases under specialist supervision.
• Pain Management:
  • NSAIDs: Non-steroidal anti-inflammatory drugs can help manage pain and inflammation.
  • Analgesics: More potent analgesics may be required for severe pain; consider referral to a pain specialist if necessary.

3. Surgical Treatments

• Incision and Drainage: Useful for acute, painful abscesses, but offers only temporary relief and is not curative.
• Laser Therapy: Nd:YAG laser can be effective in reducing hair and treating active lesions. It may help in managing mild to moderate HS.
• Surgical Excision: Wide excision of affected areas may be required for chronic, severe HS (Hurley Stage III) to remove sinus tracts and prevent recurrence. Skin grafts may be necessary for large excisions.

4. Psychological Support

• Counselling: HS can significantly impact mental health due to pain, disfigurement, and the chronic nature of the disease. Referral for psychological support or counselling is often beneficial.
• Support Groups: Encourage participation in support groups, where patients can share experiences and coping strategies.

Prevention

Prevention strategies for Hidradenitis Suppurativa focus on reducing flare-ups and minimising disease progression:

• Smoking Cessation: Stopping smoking can significantly reduce the severity and frequency of HS flares.
• Weight Management: Maintaining a healthy weight reduces skin friction and inflammation.
• Skin Care: Regular cleansing with antiseptic washes and avoiding skin irritation can help prevent new lesions from forming.

When to Refer

Referral to a dermatologist or specialist HS clinic may be necessary in the following situations:

• Severe or Refractory HS: If the disease is not responding to standard treatments or is severe (Hurley Stage II or III).
• Complicated Cases: Cases with significant scarring, sinus tract formation, or systemic symptoms may require specialist intervention.
• Consideration of Biologics: If the patient is a candidate for biologic therapy such as adalimumab.
• Psychological Impact: Significant psychological distress or impact on quality of life may necessitate referral for psychological support or counselling.

References

1. British Association of Dermatologists (2024) Guidelines for the Management of Hidradenitis Suppurativa. Available at: https://www.bad.org.uk (Accessed: 26 August 2024).
2. National Institute for Health and Care Excellence (2024) Hidradenitis Suppurativa: Diagnosis and Management. Available at: https://www.nice.org.uk/guidance/ng190 (Accessed: 26 August 2024).
3. British National Formulary (2024) Topical and Systemic Treatments for Dermatological Conditions. Available at: https://bnf.nice.org.uk/ (Accessed: 26 August 2024).