What Is Heat Rash? What Is Prickly Heat? What Causes Heat Rash?

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Main Category: Dermatology
Also Included In: Pediatrics / Children's Health
Article Date: 07 Mar 2010 - 0:00 PDT

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Heat rash, also known as miliaria rubra, prickly heat, summer rash or wildfire rash is a condition in which obstruction causes leakage of sweat into the deeper layers of the epidermis, provoking a local inflammatory reaction giving rise to the typical appearance of redness and larger blister-like lesions.

According to Medilexicon's medical dictionary:

Miliaria Rubia is an eruption of pruritic macules with small central vesicles at the orifices of sweat glands, accompanied by redness and inflammatory reaction of the skin.

People who are overweight or sweat easily are more likely to get prickly heat. Babies and children are also more prone to prickly heat because their sweat glands are not fully developed.

What are the symptoms of Heat Rash?

A symptom is something the patient senses and describes, while a sign is something other people, such as the doctor notice. For example, drowsiness may be a symptom while dilated pupils may be a sign.

Symptoms of miliaria include small red rashes, called papules, which may itch or more often cause an intense prickling sensation. These may simultaneously occur at a number of areas on a sufferer's body, the most common including the face, neck, under the breasts and under the scrotum. Other areas include skin folds, areas of the body that may rub against clothing, such as the back, chest, and stomach, etc. A related and sometimes simultaneous condition is folliculitis, where hair follicles become plugged with foreign matter, resulting in inflammation.

What are the causes of Heat Rash or Prickly Heat?

Miliaria occurs when the sweat gland ducts get plugged due to dead skin cells or bacteria such as Staphylococcus epidermidis, a common bacterium that occurs on the skin which is also associated with acne.

Other causes include spending long periods of time in bed due to an illness or a long-term health condition for example. Immobility and illness can make you sweat, especially if you have an electric blanket and other warm bedding.

Wearing too much clothing in winter or sitting too close to a fire or heater can induce a rash.

Risk can also increase if using a variety of medications. Psychotropics, which affect psychic function, behavior, or experience can raise the body's temperature. Medications for Parkinson's disease, because they can inhibit perspiration can lead to increased risk. Tranquilizers such as phenothiazines, butyrophenones, thiozanthenes and diuretic medications, or water pills that affect fluid balance in the body, can lead to higher susceptibility to prickly heat symptoms.

Diagnosing Heat Rash

Although rashes are seldom dangerous, self-diagnosis is not usually a good idea. Proper evaluation of a skin rash requires a visit to a doctor or other health-care professional. Rash is a general term that means an outbreak of bumps on the body that changes the way the skin looks and feels. A rash can refer to many different skin conditions, so consult your general practitioner to confirm type and cause.

Common categories of rash include scaly patches of skin not caused by infection, fungal or bacterial infection. Also, red, itchy bumps or patches over the body, such as on the chest and back are a sure sign of heat induced rash.

What are the treatment options for Heat Rash?

Many rashes last a while and get better on their own. It is therefore not unreasonable to treat symptoms like itchy and/or dry skin for a few days to see whether the condition gets milder and subsides entirely.

An experienced practitioner should be able to recognize rash that may require further treatment. Again, in most cases the rash of miliaria will resolve without intervention. However, severe cases can last for a number of weeks and cause significant disability. General measures should be recommended for all patients, including moving to an air-conditioned environment if possible, avoiding sweat-provoking activities, occlusive clothing, and taking frequent cool showers.

Topical antibacterials, including the use of antibacterial soaps, may shorten the duration of symptoms in miliaria rubra even in the absence of obvious superinfection. Other topical agents which may reduce the severity of symptoms include anti-itch preparations such as calamine or menthol or camphor based preparations, and topical steroid creams. However, caution should be used with oil-based preparations which may increase blockage to the sweat glands and prolong duration of illness.

A powder talc admixture containing drying milk proteins Labilin and Triclosan can be used to fight infection. The powder stays on the skin longer and treats bacteria dispersed into bed linens, providing a reasonably dry refuge area for healing. Cooling menthols help alleviate difficulty getting to sleep.

In cases where the rash has developed into open blisters, or pustular lesions, a doctor should be consulted since more aggressive, medically monitored treatment may be required.

Preventing Heat Rash

Prevention is fairly straightforward. Heat rash, prickly heat miliaria rubra or wildfire rash can be prevented by avoiding activities that induce sweating, using air conditioning to cool the environment, wearing light clothing and in general and avoiding over exposure to hot and humid weather. Frequent cool showers or cool baths with mild soap can also help to prevent heat rash when temperatures rise above normal for extended period of time.

Written by Sy Kraft (B.A.)
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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