II. Pathophysiology

  1. Lichenified skin reaction to chronic scratching (may occur while asleep)
  2. Due to localized Atopic Dermatitis in 65-75% of cases

III. Causes

  1. Pruritic Conditions
    1. Atopic Dermatitis (most common)
    2. Candidiasis, Tinea Corporis or Tinea Cruris
    3. Psoriasis
    4. Scabies
    5. Skin Cancers
  2. Exacerbating factors
    1. Heat or excessive sweating
    2. Irritation from overlying clothing
    3. Topical cleansers, lotions or other products

IV. Symptoms

  1. Severe Pruritus that interferes with sleep, and results in significant scratching (cycle of worsening)

V. Signs

  1. Characterized
    1. Red Papules coalesce to form lichenified thick, scaly localized Plaque
    2. Hypopigmentation or Hyperpigmentation may occur
    3. Excoriations from scratching
  2. Distribution
    1. Lateral calf (most common)
    2. Vulva (see Vulvar Pruritus)
    3. Scrotum (Red Scrotum Syndrome)
    4. Perianal area
    5. Wrists and ankles
    6. Upper Eyelids
    7. Posterior Neck (Lichen Simplex Nuchae from stress induced scratching)
    8. Ear canal
    9. Extensor elbow
    10. Behind ear
    11. Scalp Nodules (least common, Scalp Picker's Nodules)

VI. Associated Conditions

  1. Allergic Conditions (atopy, allergy, Asthma, Eczema, Allergic Rhinitis)

VII. Differential Diagnosis

VIII. Complications

  1. Impetigo or Cellulitis
    1. Typically dry Plaques become moist with scale, crusts and Pustules when infected

IX. Management

  1. Treat underlying cause of Pruritus
    1. See Dry Skin Management (e.g. Eczema)
    2. Consider infections (e.g. Candidiasis)
    3. Consider other pruritic skin conditions
      1. See Pruritus Causes (as well as list above)
      2. Lichen Sclerosus
      3. Lichen Planus
  2. Treat superinfected areas (Impetigo or Cellulitis)
  3. Break the itch-scratch cycle
    1. See Pruritus Management
  4. Reduce lichenification
    1. Salicylic Acid
  5. Corticosteroids for specific locations
    1. Vulva
      1. Triamcinolone 0.1% ointment twice daily until active dermatitis resolves
      2. Advance to Clobetasol 0.05% daily if refractory after 2-3 weeks
      3. Consider oral Corticosteroids if still refractory after 2-3 weeks
    2. Intertriginous areas (perianal area or behind ear)
      1. Triamcinolone 0.1% ointment twice daily until active dermatitis resolves
    3. Scalp
      1. Fluocinonide gel applied twice daily until active lesions resolve
      2. Inject intralesional Corticosteroid (Kenalog 10 mg/ml) for scalp Nodules
      3. Consider Prednisone 20 mg twice daily for 2 weeks if severe inflammation

Images: Related links to external sites (from Bing)

Related Studies