Also known as prickly heat or miliaria rubra, heat rash isn't something only babies get: it can affect teens and adults alike, especially in hot, humid climates. The frustrating itch and the accompanying pus-filled red blisters are enough to drive anyone mad, but you don't have to suffer in silence. The good news is that heat rash can be easily treated and avoided. Heat rash develops when the body overheats. When we're hot, our sweat glands become active, we perspire; as the sweat evaporates off our skin, we cool down. During hot weather, we perspire even more, and if it's humid, the sweat can't evaporate fast enough to lower our body temperature. As a result, instead of evaporating, sweat becomes trapped beneath the skin, causing damage to the surface of the skin and forming prickly bumps. The prickly or tingling sensation associated with heat rash occurs when these bumps burst, releasing the sweat. Sweat glands can get blocked during hot, humid weather and during intense exercise. Certain fabrics that don't allow sweat to evaporate effectively can also lead to prickly heat as can certain types of medication, poor hygiene and certain deodorants and anti-perspirants. It's common to develop heat rash where sweat collects, such as in skin folds, on the head, neck, shoulders, chest, back, armpits, waist, crooks of elbows and knees and wherever your clothing rubs your skin and causes friction. How to ease the itch and beat the rash Shower and bathe frequently in cool water; hot water will make the irritation worse, so keep the temperature low. Try adding a cup of ground oatmeal to your bath; this acts a natural drying agent, speeding the healing process. Baking soda can also help: add 3 tbsp to your bath water and soak for 15-20 minutes. Apply calamine or prickly heat rash lotion to calm the irritation. Anhydrous lanolin can help prevent sweat glands from becoming blocked, as well as stopping new blisters from forming. Over-the-counter antihistamine medications such as Benadryl can help to ease symptoms - use as directed. Aloe vera and aloe vera-based lotions can help to relieve the itch. After bathing, let your skin air-dry instead of using a towel. Apply a steroid cream containing 1 per cent hydrocortisone to the skin up to three times a day. Avoid wearing tight clothing, particularly when exercising. Choose loose-fitting, light clothes. The more air that can get to the skin, the better. Clothing made of natural fibres such as 100 per cent cotton is best. Unperfumed talcum powder can help to absorb excess moisture on skin folds and affected areas. Stay in the shade or in an air-conditioned room when it's hot. Don't scratch the affected area; this causes the bumps to swell and can lead to infection, so make an effort to keep your fingers from your skin - it's easy to scratch subconsciously.