The skin plays an important role in controlling the body's temperature. One way that the body cools itself is by prespiration; a process of producing sweat from the sweat glands located beneath the skin - Sweating.
Sweat from the sweat glands get to the surface of the skin through a duct, evaporates and cools the body. This phenomenon is known as Evaporative cooling.
Evaporative cooling is the reduction in temperature resulting from the evaporation of a liquid, which removes latent heat from the surface from which evaporation takes place.
Heat Rash
Heat rash is a body condition that occurs when the skin's sweat ducts are blocked during high heat and humidity, and the sweat produced in the glands cannot get to the surafe of the skin to evaporate.
It is also referred to as Prickly Heat or Miliaria.
A prolonged hot weather condition cause heat rashes as people tends sweat more during this period. Also, if humidity (water content in the air) is high i.e. the air holds as much water as it can, there is no place for sweat to go, and evaporation cannot cool the body.
However, some conditions can increase or facilitate it occurrence;
- Wearing tight clothings preventing evaporation of sweat.
- Heavy clothings.
- Using cosmetics that can block sweat ducts.
- Obesity, as there are creases (skin touching adjacent skin) which makes it difficult for circulation of air on the skin and prevents sweat evaporation.
- Intense exercise without enough ventilation
- Those who are obese, babies and those who sweat easily like myself :(, are at higher risk of developing heat rashes. Babies have immature sweat glands that aren't able to efficiently remove the sweat they produce. They can develop heat rashes if they are exposed to warm weather, are overdressed or have a fever.
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The appearance of heat rash depends upon the duration and location of where the excess sweat is deposited in the skin.
Depending on how deep the blocked sweat ducts are, heat rashes (Miliaria) are classified into three, namely:
Miliaria crystallina
This is the most common form of heat rashes. It affects the sweat ducts in the top layer of the skin and is marked by clear or white, sweat-filled blisters and bumps that break easily. No itching or pain is experienced.Miliaria rubra
It is also referred to as prickly heat. It occurs in deeper layers of the skin and is therefore more uncomfortable. Signs and symptoms include red bumps accompanied with itching or prickling in the affected area.
Occasionally, the fluid-containing sacs become inflamed and pus-filled and lead to another form of Miliaria called Miliaria pustulosa.Miliaria profunda
It is the least common. It affects the deepest layer of skin - dermis. Retained sweat leaks out of the sweat gland into the skin, causing relatively larger, tough and flesh-colored bumps. It requires medical attention as it can lead to other infections.
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Heat rash often heal and disappear on their own. Over-the-counter (OTC) medications such as topical antibacterials and anti-itch medications are sometimes recommended for use. It is also best that one stays cool, hydrated and stay in a well-ventilated environ during this period.
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