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 non-folliculocentric, asymptomatic, fragile, clear vesicles that rupture easily with prompt self-resolution.
Miliaria rubra consists of non-folliculocentric, erythematous papulovesicles with associated pruritus.
Miliaria profunda consists of non-folliculocentric, pruritic flesh-coloured 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
- presence of risk factors
- non-follicular vesicles and papules (all types)
- asymptomatic eruption (crystallina)
- clear non-inflammatory vesicles (crystallina)
- fragile vesicles (crystallina)
- paroxysmal pruritus and stinging (rubra)
- erythematous papulovesicles (rubra)
- anhidrosis (profunda)
- compensatory hyperhidrosis (profunda)
- flesh-coloured papules (profunda)
Other diagnostic factors
- desquamative healing (crystallina)
- weakness and malaise (profunda)
- dyspnoea (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 medicines
- 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) preparation
- skin biopsy
Brian L. Swick, MD
Departments of Dermatology and Pathology
Iowa City Veterans Affairs Medical Center
BLS declares that he has no competing interests.
Hobart W. Walling, MD, PhD
Town Square Dermatology
HWW declares that he has no competing interests.
John English, MBBS, FRCP
Department of Dermatology
Queen's Medical Centre
Nottingham University Hospitals
JE declares that he has no competing interests.
Andrew D. Lee, MD, FAAD
Yadkin Valley Dermatology
Affiliate of Hugh Chatham Memorial Hospital
ADL declares that he has no competing interests.
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