Exercise plays an essential role in keeping your body healthy and staving off disease. However, exercise can result in uncomfortable side effects for some people, such as the development of itchy skin. Itchy skin can develop from a variety of causes, ranging from simply brushing up against an irritant during your exercise to more serious causes, such as exercise-induced urticaria.
Irritants
One reasons why your skin may itch from exercise is from your skin coming into contact with an irritant during your exercise routine. One of the more common examples of this occurs when running on trails or in thick brush. Your skin can easily come into contact with plants like poison ivy or poison oak, or may come into contact with other plants to which you may be allergic. The skin reacts with the development of contact dermatitis, a localized skin reaction consisting of swelling, itching and possibly breaking out of a rash on the skin.
Detergents
Your skin may also itch due to an allergic reaction to the detergent used to wash your workout clothing. Detergents often include chemicals or fragrances which remain in your clothing after washing. As your body sweats and soaks your clothing and your workout clothes rub more up against your body, your skin may react to the ingredients in the detergent by causing itching or other signs of contact dermatitis. You can remedy this by using a hypoallergenic detergent as well as hypoallergenic dryers sheets or fabric softeners.
Fungus
Exercise can also cause your skin to itch by creating the perfect condition for microorganisms to thrive and infect your skin. One example of this is with fungi called dermatophytes. While these microorganisms are typically always present on your skin, increased body temperature, with the moisture provided by sweat, can help the fungi grow, resulting in an infection. A common example of this is with jock itch and athlete's foot, which both are associated with exercise and include itching as a symptom.
Exercise-Induced Urticaria
In more rare cases, itching during or after exercise can be associated with an actual allergy to exercise, commonly known as exercise-induced urticaria. Several factors may contribute to this form of urticaria, including a reaction to the change in body temperature during exercise, increased sympathetic nervous activity during exercise or even food eaten before exercise. Typically, exercise-induced urticaria results in the formation of itchy hives, flushing, swelling, redness and stomach cramps, but in rare cases, the reaction can develop into life-threatening anaphylaxis, resulting in the need for immediate medical attention.
References
- MayoClinic.com: Contact Dermatitis
- FamilyDoctor.org: Exercise-induced Urticaria (Hives)
- MayoClinic.com: Jock Itch
- MayoClinic.com: Food Allergy -- Symtpoms
- American Academy of Family Physicians; Exercise-Induced Anaphylaxis and Urticaria; Robert G. Hosey M.D, et. al.
- Poison Ivy, Oak and Sumac Information Center: Is it Poison Ivy?
