Management of Miliaria (Heat Rash)
The cornerstone of miliaria management is environmental cooling and avoiding heat/humidity exposure, as this is a self-limited condition that resolves spontaneously once sweat duct obstruction is relieved. 1, 2, 3
Immediate Environmental Modifications
- Move the patient to a cool, well-ventilated, air-conditioned environment immediately 1, 2, 3
- Remove occlusive clothing and switch to loose-fitting, breathable cotton garments 1, 4
- Avoid activities that induce sweating (exercise, hot environments) until the rash completely resolves 1, 4
- Keep affected skin areas dry and well-ventilated at all times 2, 4
Skin Care Measures
- Use lukewarm (not hot) water for bathing to avoid stimulating additional sweat production 1, 5
- Limit bathing to 10-15 minutes and gently pat skin dry rather than rubbing 5
- Apply gentle, pH-neutral cleansers rather than harsh soaps that strip natural skin lipids 1
- Do NOT apply moisturizers, creams, or occlusive products to affected areas, as greasy preparations worsen the condition by trapping heat and promoting secondary infection 1
- Avoid alcohol-containing preparations that increase skin dryness 1
Symptomatic Relief
- For severe pruritus, use oral antihistamines with sedative properties (diphenhydramine) for short-term relief, though benefit is primarily through sedation rather than direct antipruritic effect 6, 1
- Non-sedating antihistamines have minimal value for heat rash 6, 1
- Cooling antipruritic lotions such as calamine or 1% menthol in aqueous cream may provide symptomatic relief 5
Monitoring for Complications
Watch closely for signs of secondary bacterial infection, particularly Staphylococcus superinfection, which can complicate miliaria rubra 1, 4. Key warning signs include:
- Crusting, weeping, or yellow discharge 1
- Painful lesions or pustules spreading beyond the original rash distribution 1
- Failure to improve with environmental modification within 3-5 days 4
If infection is suspected, obtain bacterial culture and initiate appropriate antibiotics based on sensitivities 1. Flucloxacillin is usually the most appropriate antibiotic for treating S. aureus 6.
Critical Pitfalls to Avoid
- Never apply heavy emollients, moisturizers, or occlusive dressings to active miliaria, as these trap heat and worsen sweat duct obstruction 1
- Avoid hot water bathing or showering, which stimulates additional sweating 1, 5
- Do not use topical acne medications on heat rash, as these cause irritation and excessive drying 1
- Avoid overtreating with antiseptic creams, which can irritate the skin further 1
- Do not use topical corticosteroids for uncomplicated miliaria—this is not an inflammatory dermatosis requiring steroid treatment 1
When to Escalate Care
Refer to dermatology if:
- The rash does not resolve within 1-2 weeks of environmental modification 1
- Signs of secondary infection develop despite appropriate antibiotic treatment 1, 4
- Extensive bullous miliaria develops (rare but requires specialist evaluation) 7
Expected Timeline
Miliaria crystallina typically resolves within days once heat exposure is removed 2, 3. Miliaria rubra can take a week or longer to clear, so removal of exposure to heat and occlusive fabrics may be necessary 4. The condition is self-limited and remission is promoted by keeping affected areas cool, well-ventilated, and dry 2, 3.