Hidradenitis suppurativa

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Contents

Introduction
Epidemiology and Aetiology
Pathology
Diagnosis
Investigations
Complications
Management
References
Related Articles

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
- Pyoderma Gangrenosum
- Crohn’s disease
- Spondyloarthropathy
- Down’s Syndrome

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.

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