Heat rash is a skin irritation that happens when sweat gets trapped in the skin. It’s also known as prickly heat, sweat rash, or miliaria. The rash shows up as little red bumps and sometimes tiny blisters on the skin. The rash may itch. It may cause a prickly type of pain.
In adults, heat rash is mainly found in sweaty areas like the neck, armpits, elbow creases, under breasts, and in the groin.
Heat rash happens most often in hot and humid weather, after sweaty exercise, or when you are dressed too warmly. Heat rash usually goes away on its own and doesn’t need medical care. The best way to relieve your symptoms is to cool your skin.
Home care
Try these tips at home:
-
Bathe in lukewarm water, and use mild soap. Let your skin air dry. You can also place a washcloth dipped in cool water on the rash area.
-
Don’t scratch the rash. Scratching can delay healing. It may also cause an infection.
-
Don’t use ointments on your skin. These don’t help or prevent heat rash. Ointment tends to keep the skin warmer and block the pores.
-
Keep your skin cool and dry. Use air conditioning or a fan. Dress in lightweight, soft cotton clothing.
Follow-up care
Follow up with your doctor as advised.
When to get medical care
Contact your doctor right away if you have:
-
Chills or a fever of 100.4°F (38°C) or higher, or as advised by your doctor.
-
A dizzy feeling, nausea, or confusion. ( Call 911 for any new dizziness or confusion.)
-
Changes in the rash to a dark purple color.
-
Spreading of the rash.
-
Swollen lymph nodes in the armpit, neck, or groin.
-
Bad-smelling fluid coming from the rash.
Date Last Reviewed: 06/01/2025
© 2000-2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
