Miliaria, in all forms, is due to the occlusion or disruption of the eccrine sweat ducts at various levels of the skin due to excessive sweating in hot or humid environments.
Miliaria crystallina consists of nonfolliculocentric, asymptomatic, fragile, clear vesicles that rupture easily with prompt self-resolution.
Miliaria rubra consists of nonfolliculocentric, erythematous papulovesicles with associated pruritus.
Miliaria profunda consists of nonfolliculocentric, pruritic flesh-colored papules as a result of multiple bouts of miliaria rubra. This form of miliaria is often associated with anhidrosis of the affected skin and can result in heat exhaustion.
The main treatment of choice for all forms of miliaria is placement of the patient in a cool environment.
Miliaria is a generic term referring to a cutaneous eruption due to retention of sweat as a result of occlusion or disruption of eccrine sweat ducts. The three types of miliaria are miliaria crystallina, miliaria rubra, and miliaria profunda.
History and exam
Key diagnostic factors
- nonfollicular vesicles and papules (all types)
- asymptomatic eruption (crystallina)
- clear noninflammatory vesicles (crystallina)
- fragile vesicles (crystallina)
- paroxysmal pruritus and stinging (rubra)
- erythematous papulovesicles (rubra)
- anhidrosis (profunda)
- compensatory hyperhidrosis (profunda)
- flesh-colored papules (profunda)
Other diagnostic factors
- desquamative healing (crystallina)
- weakness and malaise (profunda)
- dyspnea (profunda)
- tachycardia (profunda)
- hyperpyrexia (profunda)
- profuse sweating
- excessive heat and humidity
- occlusive clothing
- febrile illness
- repeat episodes of miliaria rubra (for miliaria profunda)
- ultraviolet light exposure
- neonatal age
- cholinergic medications
- staphylococcal scalded skin syndrome
- atopic dermatitis
Investigations to consider
- Tzanck smear
- viral direct fluorescent antibody (DFA) or culture
- viral polymerase chain reaction
- bacterial culture
- fungal culture
- potassium hydroxide (KOH) prep
- skin biopsy
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