Last week while discussing hives, I mentioned that they can be caused by exercise, which is true. It’s a condition called exercise-induced urticaria, and is fairly common. In fact there are other allergic reactions to exercise from an irritating skin eruption to a life-threatening anaphylactic reaction.
But, most often, the rash that occurs after exercise or in hot, humid weather is your run-of-the-mill heat rash, also called miliaria or prickly heat. This rash will consist of small bumps which will sting and/or itch but are not caused by an allergy.
“Every time I exercise or get hot at all, I get a heat rash all over my upper body. It comes up when I have been exercising at the gym or outdoors playing football,” a man named Chris wrote on a health forum. A woman on the site said she did too, but not when she exercised indoors. She asked if she should just stop exercising. The short answer, of course, is no.
The Mayo Clinic explains what it is: “Heat rash develops when blocked pores (sweat ducts) trap perspiration under your skin. Symptoms range from superficial blisters to deep red lumps. Heat rash usually clears on its own. Severe forms of heat rash may need medical care, but the best way to relieve symptoms is to cool your skin and prevent sweating.”
There are four types of miliaria. They are classified by how deep the blocked sweat ducts are. Symptoms will vary. The mildest form affects the sweat ducts in the top layer of skin and is called miliaria crystalline. These fluid-filled blisters and bumps will break easily.
“A type that occurs deeper in the skin (miliaria rubra) is sometimes called prickly heat. Signs and symptoms include red bumps and itching or prickling in the affected area. Occasionally the fluid-containing sacs (vesicles) or miliaria rubra become inflamed and pus-filled (pustular) this form is called miliaria pustulosa,” Mayo tells us.
They also say that a less common heat rash, called miliaria profunda, affects the deeper layer of skin (dermis). This is identified by firm, flesh-colored lesions that resemble goose bumps.
If, after your workout, you feel dizzy, nauseated, confused or have trouble breathing go to the emergency room. These may be symptoms of heat exhaustion or heat stroke.
Also, see a medical professional if the rash lasts more than a few days or if you notice signs of infection such as: “increased pain, swelling, redness or warmth around the affected area; pus draining from the lesions; swollen lymph nodes in the armpit, neck or groin; a fever, or chills,” Mayo advises.
The trick to prevention is to control excessive sweating. Don’t exercise in the heat of the day. Do your run, walk or cycling in the early morning before it gets too hot. Be sure to drink plenty of water before, during and after exercising.
Wear clean, loose, cotton clothes that will wick away the sweat and reduce friction. Take a cool bath or shower as soon as possible after your workout and let your skin air-dry instead of toweling off. Avoid using products that contain petroleum or mineral oil as they can block pores as can some sunscreens, so be sure to read the labels. Remember, you do not want to forego using sun protection.
“Avoiding overheating may be all you need to do for mild heat rash,” Mayo says. “Once skin is cool, heat rash tends to clear quickly. More severe forms of heat rash may require ointments to relieve discomfort and prevent complications.”
Use Calamine lotion or cool compresses to calm itchy irritated skin. Anhydrous lanolin may help prevent duct blockage and stop new lesions from forming and in the most serious cases you may need a topical steroid. All are available over-the-counter, ask your pharmacist for advice.
At the end of the day, a heat rash should go away on its own. If it doesn’t, call the medico as it may not be a heat rash after all. And, get back out there. We eat everyday so we need to exercise every day!
Kathy Hubbard is a member of Bonner General Health Foundation Advisory Council. She can be reached at 264-4029 or email@example.com.