para>More common in this age group ‚
ETIOLOGY AND PATHOPHYSIOLOGY
The rash is a result of keratinous plugging of the sweat ducts, which leads to swelling of the gland (known as a retention vesicle) and extravasation of sweat into the surrounding skin, leading to irritation and itching. ‚
RISK FACTORS
- Hot, humid environment
- Occlusive bandages/clothing (1)
- High fever
GENERAL PREVENTION
- Acclimatize slowly to hot weather.
- Avoid hot and humid conditions.
- Dress appropriately for warm environmental conditions.
- Understand the self-limiting nature of the disease.
COMMONLY ASSOCIATED CONDITIONS
- Exposure to hot and humid conditions
- Neonates have immature eccrine glands, which are easy to rupture with sweating, resulting in miliaria.
- Miliaria has been associated with a rare Morvan syndrome characterized by severe insomnia, for weeks or months in a row, and associated with autonomic alterations consisting of profuse perspiration (2).
DIAGNOSIS
HISTORY
- Lesions appear after person has been in a hot, humid environment that causes sweating.
- Pruritus or prickly, mildly stinging sensation in affected body areas
PHYSICAL EXAM
- Prevalent in areas of friction caused by clothing and in areas of flexure
- Infants: trunk, diaper area, neck, axilla, face
- Pilosebaceous follicles, palms, and soles are spared.
- Fine papules and vesicles on an erythematous base (3)
- May become inflamed pustules (miliaria pustulosa) (4)
DIFFERENTIAL DIAGNOSIS
- Acne
- Folliculitis
- Viral exanthems
- Drug eruptions
- Erythema toxicum
- Yeast skin infections
- Pyogenic infections
- Syringomas
DIAGNOSTIC TESTS & INTERPRETATION
Test Interpretation
- Keratinous plugging of sweat ducts
- Sweat-retention vesicle
TREATMENT
GENERAL MEASURES
- Avoid wearing heavy, tight clothing or garments that may cause friction.
- Avoid plastic or occlusive dressings/garments in hot environments.
- Avoid excessive use of soap and contact with irritants.
- Frequent cool baths with Aveeno colloidal, oatmeal, or cornstarch mixtures.
- Provide cool, dry environment for 8 to 10 hours/day.
- Topical application of lotions containing lanolin, calamine, boric acid, and menthol
MEDICATION
- Topical lotions containing calamine, menthol, or camphor may be helpful for symptoms; over-the-counter preparations with menthol and camphor for pruritus: hydrocortisone (Cortaid) or pramoxine (Prax)
- Topical steroids to relieve pruritus: 2.5% hydrocortisone (Hytone) BID as needed for 2 to 3 days or 0.1% betamethasone (Valisone) BID as needed for 2 to 3 days; avoid prolonged usage.
- Rarely, systemic antibiotics in cases of bacterial secondary infection: antibiotic effective against staphylococci (e.g., dicloxacillin 250 to 500 mg QID for 10 days unless strain is resistant to agent)
- If sweating is secondary to fever, then antipyretic drugs may be useful.
- Precautions: Care should be taken with fluorinated steroid application in children. These agents may cause systemic effects.
COMPLEMENTARY & ALTERNATIVE MEDICINE
- Use of tannic acid has not been shown to be effective.
- Aloe vera gel may be effective for heat-related rashes.
- Oatmeal bath may help with the itching associated with miliaria (5).
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Avoid vigorous activity that causes excessive sweating. ‚
PROGNOSIS
- Benign: responds to cooling
- Avoiding causative agents is key.
COMPLICATIONS
- Secondary bacterial infections
- Miliaria profunda secondary to repeated miliaria rubra can cause anhidrosis.
REFERENCES
11 Carter ‚ RIII, Garcia ‚ AM, Souhan ‚ BE. Patients presenting with miliaria while wearing flame resistant clothing in high ambient temperatures: a case series. J Med Case Rep. 2011;5:474.22 Tabanelli ‚ M, Passarini ‚ B, Liguori ‚ R, et al. Erythematous papules on the parasternal region in a 76-year-old man. Clin Exp Dermatol. 2008;33(3):369 " “370.33 Gan ‚ VN, Hoang ‚ MP. Generalized vesicular eruption in a newborn. Pediatr Dermatol. 2004;21(2):171 " “173.44 Haas ‚ N, Martens ‚ F, Henz ‚ BM. Miliaria crystallina in an intensive care setting. Clin Exp Dermatol. 2004;29(1):32 " “34.55 Reynertson ‚ KA, Garay ‚ M, Nebus ‚ J, et al. Anti-inflammatory activities of colloidal oatmeal (Avena sativa) contribute to the effectiveness of oats in treatment of itch associated with dry, irritated skin. J Drugs Dermatol. 2015;14(1):43 " “48.
CODES
ICD10
L74.0 Miliaria rubra ‚
ICD9
705.1 Prickly heat ‚
SNOMED
- Prickly heat
- Miliaria rubra, infantile (disorder)
CLINICAL PEARLS
- Miliaria is most common in the pediatric age group.
- Topical mild steroid creams may be used to reduce symptoms.
- Avoiding hot and humid temperature is helpful in prevention and treatment.