What is the recommended management for an adult patient presenting with heat rash?

Management of Heat Rash in Adults

For adult patients presenting with heat rash (miliaria), the primary management consists of cooling the affected areas, maintaining skin dryness, and applying emollients regularly—with topical corticosteroids reserved only for persistent inflammation after environmental modifications have been implemented. 1, 2

Immediate Environmental Modifications

• Remove the patient from heat exposure immediately and ensure affected areas remain cool, well-ventilated, and dry, as this promotes spontaneous resolution of miliaria 3, 4
• Change clothing frequently if the patient continues working in hot environments, as perspiration-soaked clothing perpetuates sweat duct obstruction 4
• Avoid occlusive or synthetic fabrics; heat rash associated with flame-resistant clothing can take a week or longer to resolve even with appropriate treatment 4

First-Line Topical Management

• Apply high-lipid content emollients at least twice daily to restore skin barrier function and maintain hydration 1
• Use emollients as soap substitutes rather than traditional soaps to reduce further irritation 1
• Apply emollients immediately after bathing while skin remains slightly damp to maximize hydration retention 1
• Prescribe adequate quantities: 400-500g containers minimum to ensure sufficient supply for 2-4 weeks of twice-daily application 1

When to Add Topical Corticosteroids

If the rash persists beyond 48-72 hours despite cooling measures, or if significant inflammation is present:

• Apply mild-to-moderate potency topical corticosteroids (hydrocortisone 1-2.5% or clobetasone butyrate 0.05%) to affected areas twice daily for 2-3 weeks 5, 6
• For body areas (not face), betamethasone valerate 0.1% or mometasone 0.1% may be used if mild corticosteroids are insufficient 5
• Limit duration to 2-3 weeks, then reassess 5

Management of Superimposed Infection

Monitor closely for secondary bacterial infection, particularly Staphylococcus:

• If clinical signs of infection develop (increased erythema, pustules, crusting, warmth), take bacterial swabs from affected areas 5, 4
• Apply topical antibiotics in alcohol-free formulations (e.g., fusidic acid) for at least 14 days if localized infection is present 5
• Consider oral antibiotics (e.g., tetracycline ≥2 weeks) for more extensive or severe infections 5, 4
• Do not use topical antibiotics long-term due to resistance concerns 6

Adjunctive Symptomatic Treatment

• For pruritus, non-sedating H1 antihistamines (fexofenadine 180mg or loratadine 10mg daily) may provide relief as second-line therapy 1, 6
• Avoid topical antihistamines as they increase contact dermatitis risk 6
• Calamine lotion is not recommended for heat rash management 6, 7

Expected Timeline and Follow-Up

• Miliaria crystallina (superficial clear vesicles) typically resolves within days once heat exposure is removed 3
• Miliaria rubra (deeper inflammatory papules) may require up to 21 days for complete resolution even with appropriate treatment 8, 4
• Heat intolerance can persist for 21 days after rash development, with reduced sweat rate and elevated body temperature during heat exposure 8
• Reassess at 2 weeks: if improved, continue emollients and taper corticosteroids; if no improvement, reconsider diagnosis 6

Critical Pitfalls to Avoid

• Do not allow continued heat exposure while attempting topical treatment alone—environmental modification is essential for resolution 3, 4
• Do not dismiss extensive miliaria rubra as benign; it can cause significant heat intolerance and functional impairment for weeks 8
• Ensure adequate fabric laundering to remove detergent residue, which can exacerbate skin irritation in susceptible individuals 4
• Patients with extensive body surface area involvement (>17%) may experience prolonged heat intolerance requiring temporary work modifications 8

When to Refer

• Consider dermatology referral if no improvement after 6 weeks of appropriate therapy 6
• Refer patients with recurrent episodes despite environmental modifications for evaluation of underlying hyperhidrosis or other predisposing conditions 9