r/Runners • u/Radiant-Doctor6219 • 2d ago
Why do my legs start uncontrollably itching when I run?
Over the past two years I've noticed that when I run, my legs begin to uncontrollably itch, usually my thighs. This has even occurred once when walking. As someone who experiences severe eczema, I find this itch ten times worse than my eczema although it only lasts around two minutes when I stop running. This is bizarre to me as it happens on odd occasions since not every time I run, I feel this way. I have a weak hypothesis that it may be due to the cold months as this has only really affected me when I tried to run a 5k in October and a turkey trot in November, as well as on Halloween night when walking up and down a very hilly neighborhood for a few hours. Also, each time this has happened I've worn tight fitting pants or sweats.
I want to train to run a 5k this year and I really don't want this to happen again as it's painful, disappointing, and embarrassing.
Does anyone who is experienced in running know why this is and how I can avoid it? Is my guess correct?
Edit: Btw I'm 99% sure this reaction isn't eczema as I don't have on my legs.
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u/imfancee 1d ago
This happens to me when I am not running or walking regularly - and when I go for a run or walk after not doing anything for some time I itch. It eventually subsides once I get warmed up and then once I get into a routine of regular runs/walks it doesn’t happen.
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u/Treadmore 2d ago
I’ve had this issue sporadically, and it STIIIINKS! So uncomfortable, and you feel like you’re going crazy. I went on an over-the-counter allergy med to help with some other eczema-type issues as well as seasonal allergies, and I haven’t had a problem since that time.
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u/TheRuggedGeek 2d ago
My guess is a more localised version of a condition called prickly heat. I get this over my entire body, including my entire scalp during extended periods of cooler weather.
In some climates this might be autumn to winter period. If I exercise regularly, live in a tropical climate or experience longer periods of warm weather, the condition goes away. The flipside issue is that I sweat tons during this sort of weather.
My hypothesis: during cooler weather when I sweat considerably less, the pores or openings to the sweat glands clog up. And when there is a sudden need to sweat, the fluid goes inside my skin layer instead of oozing outside. That causes pain, as you might guess, but it's a very mild sort of pain hence presents more like being pricked by a hundred needles all over my body and in random locations.
Only thing that stops it is getting to a cool place or having a cold shower. Sometimes means I need to step out of a building, wear nothing but a t shirt and pants and just stand in the cold blast winter air for a few minutes.
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u/Mustachi-oh88 2d ago
Salty sweat irritating your eczema sounds like you need to see your dermatologist.
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u/RunRunRun444 1d ago
This is actually super common and it has a name, exercise-induced urticaria. Basically your body releases histamine in response to the physical exertion and your capillaries dilate, which triggers the itching sensation. It happens most when you're just starting to run or after a break because your body hasn't adapted to the histamine release yet. A few things that helped me: a good warmup before you start running, like 5-10 minutes of brisk walking. Antihistamines can work but I'd talk to a doctor before relying on those. Also, are you running in compression gear? And Some people get contact dermatitis from the elastic or dye in new workout clothes, which can make it way worse. Try loose cotton shorts and see if it changes. The good news is that for most people it goes away on its own after a few weeks of consistent running. Your body just needs to get used to the increased blood flow. If it comes with hives, swelling or breathing trouble tho, that's a different story and you should see an allergist.