Introduction

Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition, which manifests in the intertriginous areas (part of the skin where two opposing surface touch – e.g. armpits, groin, under breasts, perineum, buttocks and under any abdominal ‘apron’) of the body. It causes abscesses, fistulas and other nodules and inflammatory skin changes in these areas, which result in chronic scarring.

It is associated with obesity, smoking, androgen dysfunction and metabolic syndrome.

The clinical course and severity are variable. Effective treatment exists, but the most important factors are life-style based.

Epidemiology and Aetiology

  • Affects approximately 1% of the population
  • 30% of cases have a strong FHx
  • F > M – 3:1
  • Not present before puberty – hormonal factors thought to be involved
  • Mean age of onset is 21
  • Rare in Asians, common in Caucasians and Afro-Caribbean populations
  • Associated factors
    • Obesity – 60%
    • Acne – 50%
    • Hyperlipidaemia – 45%
    • Depression – 40%
    • Insulin resistance – 40%
    • Pilonidal Sinus – 25%
    • PCOS – 15%
    • T2DM – 15%
    • Hypertension – 14%
  • Associated conditions

 

Pathology

Follicular occlusion occurs (for reasons unknown) and is following by a strong inflammatory reaction. The strength of this reaction is influenced by the associated conditions outlined above, particularly by smoking, obesity and disorders of glucose metabolism.

There are likely to be microbiome factors involved in this pathogenesis.

If untreated, the disease is usually progressive.

Hidradenitis suppurativa in the axilla

Hidradenitis suppurativa in the axilla

Diagnosis

Diagnosis is made clinically, when there is the presence of all three of the following:

  • Deep, painful skin nodules
  • In typical distribution – intertriginous areas
  • Lesions are chronic and recurring

The severity of the disease can be classified according to the Hurley Staging System

  • Hurley Stage 1 – Abscess formation only (single or multiple). No fistulas or scarring
  • Hurley Stage 2 – Recurrent abscesses with sinus tracts and scarring. Can be single location, but often multiple locations
  • Hurley Stage 3 – Diffuse lesions with multiple tracts and abscesses

Definitions

  • Nodules – hard and painful lumps in the skin. Initially singular, later develop into multiple lesions. Last several weeks or months. Can later develop into pustules and abscesses which then rupture.
  • Abscess – a pus filled cavity
  • Sinus – a tract that opens on the skin surface. Occur as a result of recurrent nodules and abscesses, and often become chronic – constantly discharging blood and foul smelling discharge.
  • Fistula – a tract between two cavities

 

Investigations

Usually one are required for diagnosis, but some may be performed

  • Blood glucose – can help identify any associated diabetes or insulin resistance
  • Swab MC+S – usually negative

 

Complications

  • Scarring
    • Chronic scarring increases the irsk of SCC formation
  • Lymphoedema – can occur as the result of destruction of lymphatic drainage structures, secondary to inflammation
  • Fistula formation to other organs (rare) e.g. to urethra, bladder, rectum
  • Psychological
    • The appearance, pain, and smelly discharge caused by the lesions can have a negative psychological impact
    • Can lead to sexual dysfunction and social isolation
    • High association with depression
    • Can be managed with referral to HS support groups, as well as regular treatments for depression and anxiety
  • Arthropathy

 

Management

For many of the treatment options, the evidence base is not well established, and more research is needed.

Lifestyle Factors

  • Smoking cessation
  • Weight loss
  • Wear loose fitting clothing
  • Use anti-septic wash (e.g. chlorhexidine)
  • Assess and treat psychological factors

Managing comorbidities

  • Monitor for insulin resistance and diabetes
  • Check females for PCOS
    • Treat androgen dysfunction as appropriate – e.g. combined oral contraceptive pill, metformin, spironolactone, finasteride
  • Check lipid profile

Medical Therapy

  • Hurley 1
    • Topical agents
      • Antiseptic wash – such as chlorhexidine wash
      • Clindamycin 2% cream
    • Doxycycline 100mg OD, or Minocyclin 50mg BD for 3-4 months
  • Hurley 2
    • Oral clindamycin 300mg BD, plus Rifampicin 600mg OD
    • For 10 weeks
  • Hurley 3
    • Biologic therapy – e.g. Adalimumab SC injection weekly
    • Oral steroids – particularly useful for managing pain and flares of abscesses

Antibiotics are thought to be effective due to their immunomodulating and anti-inflammatory effects and not as a direct result of their antimicrobial action.

Adalimumab is an anti-TNF drug which should only be used under specialist supervision and requires close monitoring.

  • Anti-TNF drugs are immunosuppressant and increase the risk of infection
  • Be wary of TB in patients on these medications long term
  • Do NOT administer live vaccines to any immunosuppressed patient

Consider dermatology referral for any patients with recurrent exacerbations not responding to treatment, or Hurley stage 2 and above.

Surgical Management

  • Acute – e.g. local incision and drainage of abscess, de-roofing of lesions. I+D of focal lesions is not very effective with a recurrence rate of about 50%
  • Long-term – wide local excision of affected areas – often requiring skin grafts. Should be reserved for the worst cases that have not responded to medical management
    • Some studies suggest better outcomes with wider excision margins and grafting, as opposed to other skin closure methods
  • Surgery is the only treatment that can remove scarring and chronic sinuses and fistulae

Laser Therapy

  • Theoretically destroying the pilosebacious glands should prevent spread of the disease
  • Studies have variable results, and is not routinely recommended. More studies required to establish efficacy.

Pain Management

  • NSAIDs
  • Paracetamol
  • Consider escalating to pain management specialist if opioids or other treatment are required
  • Steroids (oral) can also help with pain caused by inflammation

References

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