II. Epidemiology

  1. Prevalence: 0.1% (U.S. 2017, increasing)
  2. More common in women by a factor of 4:1
  3. Onset age 18 to 40 years

III. Pathophysiology

  1. Inflammation of the Apocrine Sweat Glands
  2. Effects intertriginous folds with Sweat Glands and Terminal Hairs (e.g. axillary, inguinal or inframammary folds)
    1. Regions of excessive moisture and where skin rubs together
  3. Inflammatory Cytokines and Chemokines promote hyperkeratosis, follicular Occlusion and cyst formation
    1. Pilosebaceous Unit ruptures with further inflammation and secondary abscess and sinus tract formation
    2. Results in regional scarring, contractures and persistent sinus tracts

IV. Risk Factors

  1. Obesity
  2. Female Gender
  3. Black race (3 fold higher than caucasian)
  4. Tobacco Abuse (two fold increased risk of hidradenitis)
  5. Genetic predisposition to Acne Vulgaris
  6. Family History of Hidradenitis Suppurativa
  7. Apocrine duct obstruction
  8. Secondary Bacterial Infection
  9. Symptomatic flares often occur during Menses

V. Symptoms

  1. Pain, itching, burning and erythema in area involved

VI. Signs

  1. Characteristic
    1. Early
      1. Mild inflammatory Nodules (0.5 to 2 cm) or abscess
        1. Deep, painful and may persist for months
    2. Later
      1. Multiple abscess (sterile in most cases) with foul-smelling drainage
      2. Multi-headed comedones (double tombstones)
      3. Sinus tract formation
      4. Fibrosis
      5. Bridge scarring
      6. Hypertrophic Scar or Keloid
      7. Contractures
  2. Distribution (typically bilateral)
    1. Axilla (most common overall, and more common in women)
    2. Anogenital area (more common in men)
      1. Gluteal folds, perianal area and perineum
      2. Foreskin and Scrotum in men
      3. Pubis and labia in women
    3. Breasts (areola and inframmary regions)
    4. Extension onto back and buttocks

VII. Labs

  1. Not typically indicated for hidradenitis diagnosis
    1. Bacterial cultures are rarely indicated
    2. Skin biopsy may be indicated to differentiate from other conditions in region (e.g. perianal Crohn Disease)
  2. Consider additional lab testing for those with findings suspicious for underlying condition
    1. Diabetes Mellitus
    2. Thyroiditis
    3. Polycystic Ovary Syndrome

VIII. Differential Diagnosis

  1. Early
    1. Furuncle or Carbuncle (Bacterial abscess)
    2. Lymphadenitis
    3. Ruptured Trichilemmal Cyst
    4. Cat Scratch Disease
    5. Tularemia
    6. Acne Conglobata (severe nodular acne in men on back, chest, face)
    7. Pilonidal Cyst (gluteal fold)
    8. Foreign body (esp. prior surgery mesh, e.g. midurethral mesh sling for Stress Incontinence)
    9. Pyoderma Gangrenosum
      1. Painful leg Pustules that ulcerate associated with inflammatory, rheumatic and hematologic disorders
  2. Late
    1. Lymphogranuloma venereum
    2. Granuloma Inguinale (Donovanosis)
    3. Tuberculosis (Scrofuloderma)
    4. Actinomycosis
    5. Inflammatory Bowel Disease enterocutaneous fistula (Crohn's Disease, Ulcerative Colitis)

IX. Grading: Hurley System

  1. Stage 1
    1. Single or multiple abscesses
    2. NO sinus tracts or scarring
  2. Stage 2
    1. Abscess recurrence
    2. Sinus tracts and scarring
    3. Lesions are widely separated
  3. Stage 3
    1. Diffuse skin involvement
    2. Multiple sinus tracts
    3. Widespread abscess formation

XI. Precautions

  1. Hidradenitis is clinical diagnosis based on simple observation, but its diagnosis is typically delayed by 7 years
  2. Delayed diagnosis results in increased scarring, sinus tracts and more refractory course
  3. Hidradenitis results in pain, foul odor and scars
    1. Associated with decreased self esteem, Mood Disorders (including Suicidality), and decreased quality of life

XII. Management: General Measures

  1. Avoid exposure to heat and humidity
  2. Avoid shaving if it causes irritation
  3. Avoid synthetic tight fitting clothes
    1. Wear loose fitting clothing to prevent skin friction
  4. Antibacterial soaps or Chlorhexidine (Hibiclens) washes
    1. Evidence is lacking, but reasonable to try
  5. Weight loss
    1. Weight loss of 15% if Overweight
  6. Tobacco Cessation
    1. Tobacco use is associated with a 2 fold increased risk of hidradenitis, and more treatment refractory course
  7. Apply warm compresses to affected area

XIII. Management: Pregnancy

  1. Hidradenitis Suppurativa may worsen (20%) or improve (24%) with pregnancy
  2. Hidradenitis Suppurativa worsens for 60% in the Postpartum Period
  3. First Line Topical Agents safe in pregnancy
    1. Topical Benzoyl Peroxide
    2. Clindamycin Topical 1% (Cleocin-T)
  4. First Line Oral Agents safe in pregnancy
    1. Oral Cephalexin
    2. Oral Amoxicillin-clavulanate
  5. Severe, refractory cases
    1. Intralesional Corticosteroids
    2. Laser therapy
    3. Surgical excision
  6. References
    1. Erlandson (2023) Am Fam Physician 107(2): 152-8 [PubMed]

XIV. Management: Mild (Single Nodules with minimal pain) - Hurley Stage 1

  1. General measures as above
  2. First-line Options
    1. Clindamycin Topically (Cleocin-T)
    2. May also consider Topical Resorcinol 15%
  3. Second-line Options for refractory lesions
    1. Consider Intralesional triamcinolone
    2. Consider small Nodule punch Debridement or abscess drainage

XV. Management: Moderate (Recurrent Nodules, pain, abscesses) - Hurley Stage 2

  1. General measures as above
  2. Continue topical Clindamycin
  3. Initial antibiotic course is typically for 12 weeks
  4. First-Line: Tetracyclines (not in children <8 years or pregnancy)
    1. Tetracycline 500 mg twice daily OR
    2. Doxycycline 100 mg orally twice daily
  5. Second-Line
    1. Dermatology Referral
    2. Adalimumab (Humira) weekly
  6. Third-Line
    1. Clindamycin 300 mg twice daily AND Rifampin 300 mg twice daily OR
    2. Acitretin (Soriatane) OR
    3. Consider surgical Consultation for larger lesion and sinus tract excision
  7. Other measures
    1. Antiandrogens in women with cyclical flares
      1. Spironolactone 25-75 mg daily

XVI. Management: Late (abscesses, sinuses, scarring) - Hurley Stage 3

  1. General measures as above
  2. Continue topical Clindamycin
  3. Referral to Dermatology
  4. First-Line
    1. Adalimumab (Humira)
  5. Third-Line
    1. Infliximab (Remicade) OR
    2. Anakinra (Kineret) SC daily OR
    3. Clindamycin 300 mg twice daily AND Rifampin 300 mg twice daily OR
    4. Consider referral for wide, extensive surgical excision of lesions and scarring

XVII. Management: Surgical Measures

  1. Mini-Unroofing (Punch Debridement)
    1. Indicated for small, inflamed Nodules and abscesses
    2. Use a 5-6 mm Punch Biopsy at center of lesion
      1. Follow with manual expression of contents
      2. Allow to heal by secondary intention
  2. Unroofing
    1. Indicated in chronic abscesses, Nodules and sinus tracts
    2. Surface of lesions is removed with scissors, cautery, carbon dioxide laser
      1. Underlying lesion contents are curetted
      2. Allow to heal by secondary intention
  3. Nd:YAG Laser
    1. Indicated in chronic abscesses, Nodules and sinus tracts
    2. Superficial Hair Follicles are destroyed
  4. Electrosurgical Peeling
    1. Indicated in chronic abscesses, Nodules and sinus tracts
    2. Involved skin is removed in consecutive layers, preserving normal skin
      1. Allow to heal by secondary intention
  5. Wide Excision
    1. Indicated in extensive disease with scarring
    2. Wide excision of involved tissue including Nodules, abscesses, scar, sinus tracts

XVIII. Management: Other options that have been used historically in Hidradenitis

  1. Oral Contraceptives (high Estrogen, low androgen)
    1. See Androgenic Activity
  2. Accutane 0.5 to 1 mg/kg PO daily
    1. Used before surgery
  3. Corticosteroids (variable efficacy)
    1. Prednisone 70 mg tapered over 14 days
    2. Intralesional triamcinolone
  4. Cryotherapy
  5. Augmentin has previously been used for anogenital hidradenitis

XIX. Complications

  1. Rectal or Urethral fistulas
  2. Secondary infection
  3. Lymphedema
  4. Squamous Cell Carcinoma

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