Which cream helps sweat rash?

Is sweat rash the same as heat rash?

Sweat rash, heat rash and prickly heat are names for miliaria, a condition caused by blocked or inflamed sweat ducts, the small channels that carry sweat to the skin. Sweat rash and prickly heat are names for the same condition, so the extra names do not require extra products. Hot, humid conditions make the rash more common.34

Typical symptoms are small raised spots, an itchy or prickly feeling and mild swelling. The rash can appear anywhere. Spots can look red on white skin, or grey or white and less obvious on brown or black skin. Heat rash is not contagious.1

When does hydrocortisone help?

Hydrocortisone is a corticosteroid, a steroid medicine that reduces inflammation, including itching and swelling. Skin creams, ointments and lotions containing hydrocortisone can be used for heat rash. The medicine treats inflammation; keeping the skin cool remains the main step for sweat rash.15

Ask a pharmacist which treatment fits your rash. Options include calamine lotion, antihistamine tablets and hydrocortisone cream. Children under 10 need a doctor's advice before using hydrocortisone for heat rash. Do not treat a medicated cream as an ordinary moisturizer to apply whenever you feel like it: check the label for active ingredients and follow the treatment instructions.16

What should you do before applying cream?

1. 1Move into a cooler area and remove extra clothing. A fan can help cool a child.
2. 2Take a cool bath or shower. For a child, use a lukewarm bath or shower, or a cool damp washcloth to remove sweat and body oils.
3. 3Dry off excess moisture after washing.
4. 4For itching, apply a cool damp cloth or an ice pack wrapped in a tea towel for up to 20 minutes. Tap or pat the rash rather than scratching.

Loose cotton clothing and lightweight bedding help keep skin cool, so the wardrobe and the duvet get jobs before the bathroom shelf does. Avoid perfumed shower gels and creams.1

What about babies and children?

For a child's heat rash, start with cooling rather than lotions, oils, creams or ointments. These products can further block pores and trap moisture. Breathable fabrics such as cotton let air circulate and sweat evaporate. Overdressing, heavy fabrics and too many blankets can contribute to heat rash.2

In babies, heat rash commonly appears on the neck, armpits, elbow creases and groin. Older children can also develop it on the chest and back. A child with uncomplicated heat rash should act normally, without fever or other signs of illness.2

Will moisturizer or petroleum jelly help?

Emollients are ingredients in moisturizers that soften skin and relieve dryness, itching or scaling. Barrier creams help dry skin hold onto moisture, so 'barrier' is a job description rather than a universal rash solution. Petroleum jelly forms a thick, greasy coating that holds existing moisture in the skin. For heat rash, especially in children, adding a thick coating can worsen moisture trapping rather than help.26

If the problem is dry, scaling skin rather than heat rash, an emollient has a different role. Apply it gently after washing, while the skin is still damp, ideally within three minutes. Plain emollients without active ingredients can usually be used as needed for dryness. If you also use a prescription cream, follow your prescriber's layering instructions; the medicine sometimes needs to go on before the emollient.6

What if the rash started after sunscreen?

A rash after sunscreen is not automatically sweat rash. Sunscreen ingredients can cause irritation or an allergic reaction, with itching, swelling, blisters or hives. Reactions can start within minutes or be delayed for up to a day; some begin after sun exposure. Avoid a sunscreen that repeatedly causes a reaction. A fragrance free mineral sunscreen containing zinc or titanium dioxide is less likely to irritate sensitive skin.7

For a mild sunscreen reaction that persists with itching or swelling, hydrocortisone, aloe vera or petroleum jelly can help. That is treatment for a product reaction, not a reason to coat heat rash in petroleum jelly. Seek emergency help immediately if a reaction affects your breathing or makes you feel faint or unsteady.7

How long should it last, and when do you need help?

Heat rash usually improves on its own within a few days. See a doctor if it does not improve after that, or if your baby has a rash and you are worried. For children, get medical advice sooner if the rash worsens, the child acts sick, or there are signs of infection.12

Signs that need medical attention include:

• Fever or chills.
• Pain, swelling, increasing redness or warmth around a child's rash.
• Blisters, scabs or swollen glands in a child.
• A rash with red streaks, yellow or green discharge, or sudden rapid spreading. Seek emergency medical care for these signs.