Granular Hyperkeratosis

Epidemiology
  • Middle aged women
  • Infants and children linked to diaper exposure to benzalchonium chloride in laundry rinse aids
 
Pathogenesis
  • Acquired keratotic dermatosis linked to
    • Maceration
    • Use of various personal hygiene products (eg. deodorants, antiperspirans)
    • Occlusion from chemical irritation from benzalkonium chloride
  • → leads to a basic defect in the processing of profilaggrin to filaggrin
  • → leads to retention of keratohyalin granules within the stratum corneum
  • Reactive pattern rather than specific entity
 
Clinical presentation
  • Keratotic brownish-red papules that can have a conical shape
  • May coalesce in larger well demarcated plaques
  • Axilla >> inguinal and inframammary folds >> genital
 
Pathology
  • Unusual parakeratosis
    • Unusual because visible retention of basophilic keratohyalin granules within those areas of parakeratosis
  • Hyperkeratotic flexural erythema if histology is not typical
 
DDx
  • Intertrigo
    • Seborrheic dermatitis
    • Candidiasis
    • Inverse psoriasis
    • Erythrasma
  • Hailey-hailey
  • Darier disease
  • Pemphigus vegetans
  • Irritant/allergic contact dermatitis
 
Treatment
  • Corticosteroids
  • Vitamin D analogues
  • Retinoids
  • Ammonium lactate
  • Antifungals
  • Cryotherapy
  • Laser therapy
  • Oral isotretinoin
  • Antibiotics
 
Prognosis
  • Spontaneous resolution or relapses