Severe heat rash: when to get medical help

Heat rash can range from mild prickling to intensely itchy or tender inflamed patches. More concerning features include increasing warmth, swelling, pus, yellow crusts, blisters, marked pain, or rash extending beyond areas exposed to heat and sweat. These changes do not prove infection, but they warrant a clinician’s examination. Read more about [Heat Rash](/conditions/heat-rash/).

Stop heat exposure, rest in a cool environment, loosen clothing, and gently cleanse the area. Keep the skin dry and avoid rubbing, scratching, fragranced products, and thick ointments. Do not apply prescription steroid treatment unless a clinician has advised it for this episode; [Topical Corticosteroids](/treatments/medical-dermatology/topical-corticosteroids/) can be unsuitable when infection is possible. Photographing changes can help show how the rash has progressed.

Contact a healthcare professional promptly for severe pain, rapidly spreading redness, drainage, fever, chills, or a child who seems unusually sleepy or unwell. Seek emergency help for breathing difficulty, facial swelling, confusion, collapse, or a rapidly developing widespread reaction. A professional can compare the changes with other causes of [Skin Bumps](/symptoms/skin-bumps/).

Ask whether the appearance suggests heat rash, infection, allergy, or another skin condition; which cleanser or moisturizer is appropriate; and how soon you should be reviewed if it changes. Mention recent heat exposure, new products, medicines, and any fever.