What is a heat rash, also known as miliaria (prickly heat)?

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From the Guidelines

Heat rash, also known as prickly heat or miliaria, is a skin irritation caused when sweat ducts become blocked and trapped under the skin. This condition is not directly addressed in the provided evidence 1, which focuses on heat stress and exercising children and adolescents. However, based on general medical knowledge, heat rash typically appears as small, red bumps or blisters that can be itchy or prickly. Key characteristics of heat rash include:

  • Small, red bumps or blisters
  • Itchy or prickly sensation
  • Commonly occurs in hot, humid environments
  • Affects areas where skin touches skin, such as the neck, armpits, elbow creases, and groin Treatment for heat rash is usually straightforward and involves cooling the affected area, wearing loose-fitting clothing, and keeping the skin dry [(1) does not provide information on heat rash treatment, but this is based on general medical knowledge]. For relief, calamine lotion can soothe the irritation, and 1% hydrocortisone cream may help reduce inflammation. It is essential to avoid heavy creams or ointments that could further block pores. Most heat rashes clear up on their own within a few days once the skin is allowed to cool and stay dry. If the rash persists longer than a week, worsens, or shows signs of infection like increased pain, swelling, or drainage, medical attention should be sought. Heat rash occurs because the sweat glands become overwhelmed in hot conditions, particularly when there's friction from clothing or skin folds, preventing proper evaporation of sweat.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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