Section: Skin and soft tissue Sub-section: Benign skin and soft tissue Curriculum: Curriculum, page 53

Definition

Chronic inflammatory condition caused by follicular occlusive disease involving the folliculo-pilo-sebaceous units
Predominately in the groin, axilla, perineum
- Occasionally perianal/inframammary regions
Inflammation/infection of the follicular units leading to recurrent abscess
Progressing to sinus tracts with associated fibrotic scarring

Incidence

Hurley Staging System
- Stage 1 (70%): Abscess without sinus or fibrosis
- Stage 2 (25%): Recurrent abscess with sinus & fibrosis but widely spaced apart
- Stage 3 (5%) Diffuse involvement of an area with multiple interconnected tracts

Burning and itching
Hyperhidrosis
Purplish areas with multiple fistulae / sinuses
Recurrent abscesses
Usually deep “nodules”, round, not pointed, no central necrosis
Healing leaves pitted scar to dense fibrotic band & thick indurated plaques
Scaring
Axillae > groins > inner thigh > perianal > perineal > mammary > inframammary > buttocks > pubic region > scrotum > vulva > chest > scalp > retroauricular
Women – Axilla, groin, inframammary
Men – Perineal, perianal
- At perianal region: arise distal to dentate line
Different to Crohn’s that can extend proximally

Follicular occlusion results from keratinocyte proliferation causing keratinotic plugging
- Follicular occlusion will block apocrine glands as apocrine glands drain into follicles
Lead to release of pro-inflammatory cytokines triggering innate immune system > Perifolliculitis
- At this point:
  - Become infected and cause local abscess
  - Continued increased pressure and rupture of follicle into adjacent tissues with continued folliculitis leading to sinus tract formation
  - Generate foreign body response and granulomatous reaction
  - Apocrine glands are large, modified sweat glands that are found at axillae, areolae, genital & perianal + periumbilical regions only
Perifolliculitis, abscess, sinus, fibrosis

Treatment goals:
- Reduce frequency of new lesions/minimize pain and infections
- Prevent progressive scaring/fibrosis
- Minimize existing scaring/fibrosis

First line
- Antibiotics
  - Tetracycline
    - Doxycline for Hurley stage 1 as first line
  - Clindamycin and rifampin options
- Can also add
  - Anti-androgens for females
    - Cyproterone, OCP, Spironolactone, Finasteride
      - Used in women with mixed results
  - Metformin
Refractory disease
- Immunosuppression – in more moderate/severe disease
  - TNF inhibitor (Adalimumab and Infliximab)
    - Significant improvement with both agents (Humira > Infliximab)
  - Prednisone 7 day course for acute ‘flare’
Zinc supplementation (anti-inflammatory and anti-androgen) (90mg/day)
- 30% complete response and 70% reduction in sx
Isotretinoin (Roaccutane)
- Retinoid related to vitamin A
- Limited benefit ~ 50% found some benefit but high non-compliance due to side-effects.

Should be used in conjunction with lifestyle change and medical therapy
Acute abscesses treated by drainage
- Lay open fistulae/ de-roofing with healing by secondary intention
Hurley III or Resistant II
- Wide excision of affected area
- Either primary close or ± skin graft or flap
Axillary excision oriented transversely
Groin longitudinally
Use of suction dressings prior to grafting to allow granulation tissue to form