What does each rash look like?
| Clue | Heat rash | Eczema |
|---|---|---|
| Cause | Sweat glands become blocked, with excessive sweating a key factor. | Several types of skin inflammation; atopic dermatitis is the most common. |
| Appearance | Small, shallow bumps, blisters or spots containing pus. | Dry, itchy patches; scratching can increase swelling and irritation. |
| Location | Mainly the trunk, including the chest and back. | Often the face, inner elbows, behind the knees, hands and feet. |
| Pattern | Linked to sweating and overheating. | Often long lasting, with periods of improvement and worsening. |
| Who gets it | More common in young children. | Atopic dermatitis is most common in babies and children, but adults get it too. |
| First approach | Cool the skin and reduce heat exposure. | Avoid irritants and use appropriate skin care; medicines are sometimes needed. |
Do not judge eczema by redness alone. Eczema can look red, dark brown, purple or gray depending on skin tone. Dryness, itching and the pattern of affected areas are useful clues even when a colour change is less obvious. Eczema is not contagious.23
Could it be a reaction to something touching your skin?
Eczema is an umbrella term, not just atopic dermatitis: contact dermatitis is another type. It develops when something irritates the skin or triggers an allergic reaction. Clues include a rash after using a personal care product, wearing jewelry or handling an irritating material. Contact dermatitis can cause intense itching, burning, stinging, cracks, blisters or oozing. Continued exposure can leave skin thickened and scaly. An allergic reaction can take time to appear, so the last thing you touched is not necessarily the culprit.25
Write down when the rash started, where it appeared and what touched the area, giving your calendar a brief career in skincare. A dermatologist can use that history to assess the rash and arrange patch testing, a special allergy test, if allergic contact dermatitis is suspected.3
A rash under gloves or protective equipment is not automatically heat rash. Equipment can trap heat, while sweating inside gloves, friction and materials in the equipment can also cause contact dermatitis. The same setting can therefore produce different skin problems.6
What should you do next?
- For a rash linked to heat and sweating, start by cooling down and limiting time in the heat. Calamine lotion may soothe heat rash.
- For dry, recurring patches, avoid soaps, fabrics or lotions that irritate the area. Eczema treatment can include skin creams and medicines, depending on the type and severity.
- For a suspected contact reaction, stop applying the product that appears to trigger it. Once an allergen is identified, avoiding it is the main treatment.
- Choose fragrance free rather than unscented personal care products when avoiding fragrance. Unscented products can still contain fragrance.
The words "clean" and "natural" are not regulated product categories, however tidy they look on a bottle.3
When does a rash need medical help?
Arrange a dermatology appointment if you cannot identify the rash or suspect a product reaction. Contact allergy can mimic eczema or develop on top of it. Avoid scratching: it can damage skin, worsen eczema and increase infection risk.3
Get emergency help for confusion or dizziness with signs of heat illness. For a child with a rash, difficulty breathing, sudden mouth or throat swelling, unusual unresponsiveness, or bruise like spots that do not fade under a glass require emergency care. Seek urgent medical advice for a rash with a temperature of 38°C or higher in a baby under 3 months, or 39°C or higher in an older child.47
Where this answer comes from
- 1Heat and colddermnetnz.org
- 2Eczema | Dermatitis | Atopic Dermatitismedlineplus.gov
- 3What's causing your child's itchy rash?aad.org
- 4Heat Illness: MedlinePlusmedlineplus.gov
- 5Eczema types: Contact dermatitis signs and symptomsaad.org
- 6Personal protective equipmentdermnetnz.org
- 7Rashes in babies and childrennhs.uk
