Miliaria, Miliaria rubra, Miliaria Alba, Miliaria Sudamina, Apocrine Miliaria, Miliaria Crystallina, Miliaria Profunda, Heat Rash, Sweat Rash, Lichen Tropicus, Prickly Heat, Fox-Fordyce Disease

  • Pathophysiology
  1. Sweat retention when Eccrine Glands (Sweat Glands) partially close or are obstructed by Stratum Corneum
  2. Provoked by excessive sweating
  3. Similar pathophysiology to Milia, but these two conditions are not the same
  • Epidemiology
  1. Occurs in all ages, but more common children (and 40% of newborns) whose Sweat Glands are under-developed
  • Types
  • Common
  1. Miliaria Crystallina (Miliaria Alba, Miliaria Sudamina)
    1. Sweat infiltrates below Stratum Corneum
    2. Vessicles 1-2 mm without surrounding erythema on head, neck and trunk
      1. Noninflammatory Vesicles resemble water droplets
      2. Each vessicle ruptures and then desquamates and resolves within days
  2. Miliaria rubra (Heat Rash, default type of Miliaria)
    1. Sweat infiltrates deeper, below Epidermis
      1. Inflammation associated with Sweat Gland obstruction
    2. Pruritic erythematous Papules and Vesicles on covered (over-heated) skin
  • Types
  • Other
  1. Apocrine Miliaria (Fox-Fordyce Disease)
  2. Miliaria Profunda
    1. Limited to hot, humid climates
    2. Follows severe Miliaria rubra
  • Symptoms
  1. Pruritic
  • Signs
  1. Erythematous Papules, Pustules or papulovesicular lesions
  2. Distribution
    1. Intertriginous areas and occluded areas
    2. Areas of friction (where clothes rubs against skin)
  • Differential Diagnosis
  • Management
  1. No treatment is needed
  2. Stay in cooler environment
  3. Change clothing to breathable, clean, dry, cotton
  4. Avoid lotions (occlusive and may obstruct Sweat Glands)
  5. In newborns, resolves spontaneously in first few months of life
  • Prevention
  1. Avoid Occlusion and excessive heat
  2. Avoid over-dressing
  3. Consider cool baths (avoid prolonged exposure due to Hypothermia)
  4. Stay in cool air conditioned environments
  • References
  1. Salinas and Ruttan (2017) Crit Dec Emerg Med 31(9): 3-10
  2. Feng (1995) Cutis 55:213-6 [PubMed]
  3. O'Connor (2008) Am Fam Physician 77:47-52 [PubMed]