How to treat sweat rash, heat rash or prickly heat-A simple guide from dermatologist

Written By Dr Surbhi, MD Skin

Last updated: 26/11/15
“My son gets rashes which feel like the pricking of needles every year when the weather gets hot and humid. Is this heat rash? What causes heat rash? How to prevent it? How to treat it?”

Yes! This is a typical presentation of sweat rash, heat rash or prickly heat dermatologically termed as Miliaria Rubra. I will address all these questions in this article, along with simple precautions that can save your child from bothersome rash and discomfort of itching. 

 

What is prickly heat?

Prickly heat, sweat rash or heat rash is a rash that commonly occurs due to excessive sweating in hot weather coupled with the inefficient evaporation of sweat from the surface of the skin. The rash can occur at any age but is more prevalent in newborns or children.

What causes heat rash?

You cannot win the battle without knowing your enemy well. Understanding the detailed mechanism behind a heat rash would help you spot the behaviour which triggers this rash:  

  • The first factor that comes into action is excessive sweating as can occur in hot weather or due to strenuous work or exercise.
  • The second factor that triggers a heat rash is inefficient evaporation of sweat from the surface of the skin. This can happen when the sweat ducts are blocked either by an increased number of bacteria that live harmlessly on your body or due to the tight fitting synthetic cloth that does not allow evaporation of sweat to occur. 

For the same reason, obese individuals develop prickly heat commonly in body folds as these areas are devoid of air circulation due to skin-to-skin contact. Bedridden sick persons might get prickly heat in areas which remain in contact with the bed. Children and newborn are more susceptible to prickly heat because their sweat ducts are narrower, and quickly blocked.

How does heat rash present itself?

Heat rashes start after few days of repeat exposure to hot and humid weather commonly seen on the body folds like the neck, armpits, folds of the elbow, groin and knees. However, it can occur anywhere on the body if you are wearing tight fitting clothes. The skin gets red and swollen, studded with small red bumps along with intense itching and prickly feeling.

 How to prevent heat or sweat rash?

  • Avoiding hot and humid weathers even for few hours per day can help in preventing episodes of heat rash.
  • So, if possible, you should stay in an air-conditioned room especially during the hottest part of the day.
  • Frequent baths with cold water might also help.
  • Beside this, you should wear loose-fitting cotton clothes that allow sufficient circulation of air on the surface of the skin to facilitate evaporation of sweat.
  • In the case of a newborn, do not overdress the little one or do not bundle them up too tight.
  • The posture of sick persons should frequently be changed to avoid the rash and pressure sores.
  • Similarly, obese people should pull the skin apart at folds and let it air dry.

How to treat heat rash?

Prickly heat is self-limiting, and the episodes soon stop after the exposure to hot and humid climate ceases. Also, these simple measures can help in soothing your irritated skin:  

  • Apply calamine lotion to soothe the irritated skin.
  • Cool compresses with a cloth dipped in cold water might help.
  • Take frequent showers with cold water with fragrance-free mild liquid cleanser.
  • Avoid towelling, instead, let your skin air dry.
  • Do not apply creams or ointments as they may further block the pores and worsen the rash.
  • Remain hydrated by drinking at least 2-3 litres of water daily.
  • OTC steroid creams can be applied if the rash is not responding to the above.
  • You might be more prone to heat stroke and experience decreased capacity to work because of the inability of your body to lose heat efficiently after the episode of heat rash. So, avoid strenuous work in hot weather especially if prickly heat involves a large part of your body.

When should I visit a Dermatologist?

Dermatologist visit is warranted if the above measures are not helpful in reducing the heat rash. If you notice pustules on the rash, then you might need a prescription for antibiotics. Also, fever can occur either because of infection or due to overheating of the body which warrants for an expert opinion.


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