Heat rash or prickly heat
What is heat rash or prickly heat?
Prickly heat, or heat rash, is a harmless but very itchy skin rash with small red spots all over the affected areas. It is common in Australia in hot and humid areas.
What causes heat rash?
The rash is caused by a blockage and inflammation of sweat ducts during times of exposure to heat and high humidity. These blocked sweat ducts cause sweat to escape into adjacent tissue thus producing the itching and prickling sensations associated with the condition.
What are the symptoms of prickly heat?
- Tiny red spots, which usually appear on areas of the body where sweat collects, such as the armpits, back, under the breasts, chest, groin, crooks of elbows and knees, and the waist.
- Irritating itch and prickling sensation.
- Redness and mild swelling of the affected area.
What you can do
Treating heat rash is simple and usually does not require medical assistance. Other heat-related problems can be much more severe.
- Wear light, loose-fitting soft clothes. Avoid clothing that traps heat and moisture. Natural fabrics such as cotton are best.
- Stay in cool or air-conditioned, or well-ventilated environments. Use a fan if necessary.
- Take frequent cool baths or showers. Dry yourself thoroughly and dust bland types of powder (such as unperfumed talcum powder) on body creases and affected areas, and use an antiperspirant.
- Apply calamine lotion or prickly rash lotions to soothe the affected areas, but avoid using ointments or creams — they keep the skin warm and moist and may make the condition worse.
- Ask your doctor or pharmacist about using antihistamines or a low-dose steroid cream or lotion.
- Do not scratch.
Last Reviewed: 16 December 2009
- 1. DermNet NZ [website]. Miliaria (updated 2009, June 15). Available at: http://dermnetnz.org/hair-nails-sweat/miliaria.html (accessed 2009, Dec 17)
2. Miliaria [revised February 2009]. In: eTG complete [Internet]. Melbourne: Therapeutic Guidelines Limited; 2009 Nov (Accessed 2009 Dec 17.) http://www.tg.org.au/