Does sweating cause rashes?

Why does sweat cause a rash?

Sweating is your body's cooling system, and sweating more during exercise or hot weather is normal. Heat rash, also called prickly heat, develops when sweat cannot reach the skin's surface through the tiny tubes called sweat ducts. Trapped sweat causes inflammation. Tight clothing, intense exercise and hot, humid weather increase the risk. Babies are particularly susceptible because they cannot control their temperature as well as older children and adults.145

What does a sweat rash look like?

Heat rash usually causes small raised spots, an itchy or prickly feeling and mild swelling. Some spots contain fluid. The rash looks red on white skin, but can look grey or white and be harder to see on brown or black skin. It can appear anywhere and spread across the body, but you cannot pass heat rash to another person.5

Is every rash after sweating heat rash?

• A rash in skin folds can be intertrigo, irritation caused by skin rubbing together. Sweat keeps the folds moist and increases friction. Common sites include the armpits, under the breasts, the groin and inner thighs. The rash can sting, burn or become raw. Intertrigo itself is not an infection, though bacteria or fungi can cause a secondary infection.
• Itchy, tender bumps resembling pimples can be folliculitis, an infection of the openings where hairs grow.
• Sweat mixing with skin oils and bacteria can clog pores and contribute to acne breakouts.
• A rash can also come from contact dermatitis, irritation or an allergic reaction to something touching your skin, such as strong soaps, fragrances or cosmetics.

What should you do for heat rash?

1. 1Move somewhere cooler and remove clothing covering the affected area.
2. 2Gently wash the skin with cool or lukewarm water, then pat it dry without scrubbing.
3. 3Leave the area uncovered where practical, or wear clean, loose cotton clothing.
4. 4Apply a cool damp cloth, or an ice pack wrapped in a towel, for up to 20 minutes to ease itching.
5. 5Pause activities that cause heavy sweating while the rash heals. Pat or tap itchy skin instead of scratching.

Avoid perfumed shower gels and creams. Thick creams, ointments and powders that block pores can make heat rash worse. Ask a pharmacist about treatment if itching is troublesome; options include calamine lotion, antihistamine tablets or hydrocortisone cream. Children under 10 need a doctor's advice before using hydrocortisone. Heat rash usually improves within a few days once the skin stays cool and dry.15

How can you prevent another rash?

Wear loose cotton clothing that lets skin breathe, even if the gym kit has a more ambitious job title. Exercise during the coolest part of the day or indoors with air conditioning. Change out of tight workout clothes and shower immediately after exercise. Wash sweaty clothes, hats, headbands and towels before using them again. Blot sweat with a clean towel rather than rubbing it off, because a towel does not need a second career as a polishing machine.16

Repeatedly wet skin can soften, peel and chafe. Heavy sweating even while resting in cool conditions, or sweating that interferes with daily activities, can be signs of hyperhidrosis, meaning more sweat than your body needs for cooling. Mention these patterns when seeking care for recurring rashes.7

When should you get medical help?

See a doctor if suspected heat rash does not improve after a few days, is painful or intensely itchy, or keeps returning in your child. Get prompt medical care for fever, chills, warm or swollen skin, pus, or red streaks. Seek emergency help for a sudden rash that spreads quickly, trouble breathing or facial swelling. If your baby has a rash and you are worried, contact a doctor.135