Heat rash is (unfortunately) common. Newborn babies and young children in particular suffer from it, but it can also occur spontaneously at a later age. Dangerous? Not necessarily, but heat rash can be very annoying. We will tell you how this occurs and what you can do to get rid of these red itchy blisters.
What is heat rash?
First things first: what exactly is heat rash? Jetske Ultee, skin doctor and research doctor in cosmetic dermatology, explains to us that heat rash is actually the result of irritated and blocked sweat glands. ‘When you sweat, this is the skin’s way of losing heat. But when it is very hot, those sweat glands have to work extra hard to cool the skin. Sometimes so much perspiration is released that the skin becomes clogged, as it were. This means the sweat has nowhere to go, causing a red rash and (clear) blisters. This can also cause itching.’
Difference between heat rash and sun allergy
Ultee tells us that heat rash is often confused with sun allergy. “An allergic reaction to sunlight, however, looks very different,” says the dermatologist. ‘A sun allergy often occurs in the spring, when your skin is not yet used to the sun (due to the winter). The bumps that occur due to a sun allergy are not blisters, which is the case with heat rash. The complaints of sun allergy are therefore simply the result of a hypersensitivity of the immune system to UVA radiation.’
How does heat rash occur?
As we mentioned above, heat rash occurs when the sweat glands have to work hard due to warm temperatures. By the way, it doesn’t have to be scorching hot outside to develop heat rash: when it’s hot and humid outside and you’re busy exercising, you can also get heat rash. Ultee also mentions a number of other causes of rashes after sun exposure:
- Cosmetics – Some cosmetic products (even sunscreen) contain so-called phototoxic components: substances that cause a ‘light’ reaction in the skin. Well-known culprits are fragrances and dyes, but certain sunscreen filters such as oxybenzone can also cause a rash. The complaints are comparable to a sunburn with pain and swelling. Phototoxic substances can age the skin and cause pigment spots if used for long periods in combination with the sun.
- Medicines – Certain medicines can also cause a skin reaction in combination with sun. Ultee says that this is the case with certain antibiotics, some antidepressants and water tablets. ‘This is always clearly stated in the package leaflet, so it is useful to check it.’
- ‘Margarita rash’ – This summer ailment sounds a lot tastier than it looks. Although this skin condition is still relatively unknown, many skin experts warn every year about the so-called margarita rash. ‘This rash is a nasty skin reaction due to a combination of citrus extracts and sun exposure.’ Therefore, be careful when wiping fruit juices on your arms, legs or chin. In some cases this can cause a rash, blisters or even burns. Also consider cutting celery, lemons and even parsley in the sun.
What can you do about heat rash?
Now the most important question remains: what is the step-by-step plan for annoying red blisters that itch? Ultee gives a few tips. ‘The most important thing is to cool down. Avoid sunlight and don’t exercise in the heat for a while.’ Would you like to help your skin lose heat faster? ‘You can cool your skin with wet cloths. In addition, wear clothing that fits loosely and comfortably, and that ventilates well (preferably cotton) so that perspiration can evaporate. Keep your skin clean so that the sweat glands cannot clog further and avoid greasy ointments. These will hinder water evaporation and worsen the problem.’
To be sure, check the ingredients list of your (sun) cream or make-up carefully. These are irritating plant extracts that you also want to avoid:
- Citrus
- Orange
- Bergamot
- Mandarine
- Grapefruit
- Lime
- Lavender
- Rosemary
- Five
- Angelica
- St. John’s wort
- Tea tree
- Ginger
Heat rash is annoying, but will usually go away within a few days. Is your skin very red and irritated? Or do you suffer from itching a lot? According to Ultee, a bath with oatmeal can provide relief. ‘Sprinkle about 40 to 50 grams of oatmeal in a bath with lukewarm water and remain in the bath for about 15 minutes. It can also be nice to cool the skin with compresses of milk, diluted with water.’
Do the complaints not go away after a few days? Are you unsure whether there is an allergy? Then consult a GP or dermatologist.
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Research doctor in cosmetic dermatology
Dr. Jetske Ultee is a skin expert and research doctor in cosmetic dermatology. She is convinced of the value of good skincare and likes to share her knowledge to prevent too much nonsense from being spread about dermatology.
