miliaria rubra (prickly heat)

Etiology

• caused occlusion of sweat glands in the mid to lower layers of the epidermis
• NaCl from dried sweat & thermal injury have been implicated in the pathogenesis
• greasy topical agents & clothing may also block sweat glands

Epidemiology

• very common in hot, humid areas & may also occur in hot, dry areas if pores are blocked by clothing

Clinical manifestations

• erythematous papulovesicular rash
• stinging, pruritic lesions, pinhead size
• distribution:
  • face
  • neck
  • upper trunk
  • clothed areas
  • sparing palms & soles
• symptoms worse with onset of sweating

Laboratory

not useful in diagnosis of miliaria

Differential diagnosis

• folliculitis: miliaria rubra is distinguished by its non-follicular distribution
• papular urticaria: more erythematous than miliaria rubra
• erythema toxicum: more erythematous than miliaria rubra

Management

• common to all forms of miliaria
  • moving to cooler environment
  • application of cool compresses
  • wearing light, loose-fitting clothing
  • avoidance of greasy topical agents
  • natural desquamation
  • ensure adequate hydration
• The stinging of miliria rubra may be relieved by anhydrous lanolin or calamine lotion

More general terms

• miliaria (heat rash, sweat rash)