Sweat, heat rash and the school day

It's 3:30pm in late January. Your child walks through the door, drops their bag, and starts scratching. You lift their shirt and see a scatter of tiny red bumps across their back, chest or neck. Chances are, it's heat rash.

What is heat rash?

Heat rash, known medically as miliaria, happens when sweat ducts become blocked. Instead of reaching the skin's surface and evaporating, sweat gets trapped underneath. The result is small bumps or blisters that can itch, prickle or sting. That's why it's also called prickly heat.

It's very common in hot, humid weather, and children are prone to it. It usually appears where:

Skin is covered by clothing, especially tight or synthetic clothing
Skin folds meet, like the neck, armpits, elbows and groin
Sweat can't easily evaporate, such as under backpack straps and waistbands

How school days set the scene

A school day in an Australian summer has several ingredients for heat rash:

Long wear. Kids are in the same clothes for eight hours or more.
Bursts of activity. Running at recess and lunch makes sweat, then sitting in class lets it settle.
Layering. Shirts tucked into shorts, tights under dresses, jumpers on cool mornings that stay on all day.
Backpacks. Heavy packs press fabric against the back and block airflow.
Fabric choice. Fabrics that don't absorb sweat or let vapour escape can keep skin damp and warm.

No single factor causes heat rash, but they build on one another.

What clothing can do

The aim is to keep skin cool and dry enough for sweat to evaporate freely.

Breathable fibres. Cotton absorbs light sweat and lets moisture move into the air. Standard polyester absorbs very little.
Looser fits. A relaxed cut lets air circulate. Tight collars and waistbands trap heat.
Lighter weights. A lighter summer shirt or dress makes a big difference over a whole day.
No unnecessary finishes. Water- and stain-repellent coatings can work against moisture moving away from skin.
Soft seams and labels. Rough seams rub damp skin and make irritation worse.

Easing heat rash at home

Most heat rash fades quickly once the skin cools down. Some simple steps:

Get your child out of their uniform and into loose cotton clothing after school.
Cool the skin with a lukewarm shower or bath, then let it air dry.
Avoid heavy creams and ointments, which can block sweat ducts further.
Keep fingernails short to limit damage from scratching.
Offer plenty of water.

See your GP if the rash doesn't settle within a few days, if your child has a fever, if bumps become painful or filled with pus, or if you're unsure whether it's heat rash or something else, like eczema or a contact allergy.

Talk to the school

Many Australian schools already allow hats, shade and water breaks in summer. It's also reasonable to ask whether children can remove jumpers, loosen ties, or wear sports uniform on very hot days. Some schools have made these changes after hearing from parents.

Designed for warm days

We're designing Natural Schoolwear summer uniforms in lightweight natural fibres, cut with room to move and without chemical coatings. Our goal is simple: children who come home ready to play, not ready to scratch.

This article is general information, not medical advice.