Miliaria (Heat Rash, Prickly Heat)
Last
updated 10.12.13
Definition
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Epidermal or dermal skin rash from obstruction of eccrine sweat glands
Features
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Sweat glands become blocked & sweat accumulates under the skin causing mild inflammation
- Typically lasts hours to days & is self limiting
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If significant area effected can contribute to heat exhaustion/strok due to impaired hearing
Types
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Miliaria crystilline (clear): vesicles only
- Miliaria rubra (red): larger blisters with inflammation & sensation = prickly heat
- Miliaria pustulosa (yellow): when pus accumulates in blisters
- Miliaria profunda (deep): chronic effect, effects dermis, causes deeper, harder, larger lumps
Miliaria Crystilline
Miliaria Rubra
Miliaria Pustulosa
Risk Factors
- Humid environments
- Opposed areas of skin: creases, etc,
- Non-breathable &/or tight clothing, bandages, patches
- Excessive sweating
- Heavy creams or lotions: sunscreen, make up
- Medications: Clonidine, Isotrenitoin
- Newborns (fever, excessive clothing, warm weather), elderly
- Type 1 pseudohypoaldosteronism
Associated S/S
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Rash: erythematous vesicles
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Any body part but typically face, neck, back, abdomen, groin, elbow folds, buttocks, submammary
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Prutitus or prickly sensation: may feel similar to sunburn
Complications
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Secondary infection = miliaria pustulosa
- Heat related injury: heat exhaustion, heat stroke
- Heat intolerance: weakness, fatigue, dizziness (topical anhydrous asthenia)
DDx
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Candida
- Folliculitis
- HSV
- Erythema toxicum neanatorum
Ix
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Typically not required
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Consider biopsy if usure or atypical features
Mx
- Cooling of effected pars
- Avoid trigger: creams, meds..
- Topical agents
- Calamine lotion
- Anhydrous lanoline for miliaria profunda
- +/- Antibiotics if secondary infection
- Prevention
- Breathable loose fabrics: cotton
- Air conditioning
- Keep skin clean with frequent washing
- Adequate hydration
- Acclimitisation
References