How to treat a skin rash from sweating

Is sweating actually causing the rash?

Heat rash is skin irritation from excessive sweating and is more common in young children. Hot, humid weather can also trigger or worsen other rashes. Tight, heavy clothes trap heat and moisture, giving your workout clothes an unexpectedly enthusiastic second career as a greenhouse.12

Contact dermatitis happens when something irritates the skin or causes an allergic reaction; getting rid of it means finding and avoiding the cause. A rash appearing after sweating does not identify its cause, however persuasive the timing looks on your mental incident report. Blotches, welts and blisters can all be forms of a rash.3

What should you do first?

1. 1Move to a cool, ventilated place. Limit further time in the heat rather than continuing to exercise or work outdoors in high temperatures.
2. 2Take a cool or lukewarm shower to wash off sweat. Keep the shower brief rather than soaking for a long time.
3. 3Put on loose cotton clothing. Avoid tight clothing and irritating fabrics such as wool or synthetics while the skin is itchy.
4. 4Hold a cool, damp towel against itchy skin. Pat or tap the area instead of scratching, and keep your nails clean, short and smooth.
5. 5Use an unperfumed moisturiser regularly if the skin is dry or irritated. Avoid perfumed soaps, deodorants and moisturisers on itchy skin.

These are general measures for easing itch and irritation, not a treatment for every possible rash. Use cooling measures when the skin is itchy and keep heat and humidity exposure down. A laundry liquid or powder intended for sensitive skin is another option if clothing is irritating the area.45

Should you use hydrocortisone or an antihistamine?

Hydrocortisone cream and antihistamines are options for some causes of itching, but the right medicine depends on what is causing the rash. Ask a pharmacist which cream or tablet fits your symptoms rather than treating every sweaty rash the same way. Tell them where the rash is and whether you have other symptoms.145

When should you see a doctor?

Arrange medical advice if the rash does not improve after a few days in a cool place, covers a large area or keeps returning. Seek care for warmth, pus, fever or other signs of infection. Severe itching, itching that disrupts daily life and itching all over the body also need assessment.145

During pregnancy, check itching with a doctor or midwife. It can sometimes be caused by a liver condition called intrahepatic cholestasis of pregnancy. Excessive sweating during pregnancy also needs medical advice if it comes with fever, chills or vomiting.46

If sweating is new, unusually heavy or happens without heat or exercise, contact your healthcare provider. Sweating that soaks clothing or bedding can have an underlying cause, including a medication. If medicine is responsible, a clinician can consider changing the dose or prescription; rash care alone will not address that cause.6

Get emergency help for a rash with difficulty breathing or swelling of the lips, tongue or throat. Confusion or loss of consciousness in the heat also needs emergency help. These symptoms call for urgent assessment, not continued home treatment of the rash.1