Itching during exercise can have many causes, most of which can be remedied with little effort. To determine what is causing your discomfort, consider the environment, your clothing and any previously diagnosed skin conditions such as eczema. If the condition is extreme or covers a majority of your body, see your doctor for a proper diagnosis. Making a few minor changes when exercising may be enough to cure the itch.
Chafing
The most obvious problem that might be causing your itch is chafing. Chafing occurs due to skin irritation, and though it may start as an itch, it can become more severe soon thereafter. Chafing is the result of friction. Clothing that is too tight or rubbing against the skin can lead to itchy skin that eventually becomes inflamed. To remedy this problem, wear different clothes when you exercise, or apply petroleum jelly or baby powder to the affected area.
Heat Rash
If you are exercising outdoors in hot weather, the itch may be heat rash. In this case, the discomfort is from blocked sweat ducts where sweat becomes trapped under the skin. Other symptoms of heat rash include blistering and red, bumpy areas on the skin. To treat the condition, Mayo Clinic recommends calamine lotion as opposed to an ointment or cream. Also, exercise in a cooler environment. If you keep skin dry and avoid sweating, the rash should clear on its own. If the affected area starts to ooze or red streaks develop in the skin, see your doctor to determine if the rash is infected.
Tinea Cruris
Tinea cruris is more commonly known as jock itch. Even though the name would seem to indicate the condition is exclusive to males, this is not true. This form of itch is prevalent among athletes and people who are overweight, but anyone can get it. It is a fungal infection the shows up in the genital area, inner thighs or buttocks in the form of a ring-shaped rash that itches. There are over-the-counter treatments available if the rash is minor. For a severe case, see a doctor for stronger prescription medication.
Contact Dermatitis
Contact dermatitis is an allergic reaction to something touching your skin. The rash may be caused by new sneakers, fabric or something you brush against, such as a plant. Dermatitis presents as an itchy red rash that is contained to a certain area. For example, a reaction to new sneakers would only be on your feet and probably look like the outline of the shoe: the rash would stop exactly where the shoe stops. The most effective treatment is to avoid the allergen. If you cannot figure out what you are allergic to, try a topical hydrocortisone cream and an oral antihistamine. See your doctor if the skin begins to weep or ooze. This may indicate eczema or an infection.
Exercise-induced Anaphylaxis
A less likely culprit, but certainly more serious, is an allergic reaction that only presents with physical exertion. Although not common, this condition may have little to do with your exercise. Unlike contact dermatitis, the allergen is probably a food source, such as shellfish. Symptoms of exercise-induced anaphylaxis include a rash with warm, flushed skin and possibly hives. If you see hives on your skin, it is critical that you stop exercising, as it may be triggering the reaction. See your doctor as soon as possible. He may require that you carry epinephrine injector with you at all times. It is also important to determine what you are allergic to, and that may require sensitivity tests. If while working out you feel tightening in your throat or if there is swelling in your mouth or anywhere on your body, stop and seek immediate medical help. Anaphylaxis can become a medical emergency very quickly. Go to the hospital or ask someone to call 911.
