The Complete Guide to Itchy Skin During & After Exercise (+ Free Relief Checklist)
The Complete Guide to Itchy Skin During & After Exercise (+ Free Relief Checklist)
Medically reviewed by Susan Nedorost, MD, Professor Emerita of Dermatology, Case Western Reserve University. Currently practicing at Dermatologists of the Central States, Dublin, Ohio.
Every time you hit the gym, step on the trail, or roll out your yoga mat, your goal is to feel good moving.
Instead your skin flares with itching, red patches, or rashes that sometimes linger well beyond your workout.
Itchy skin during exercise - and even after - are surprisingly common. However, the triggers aren’t always easy to pinpoint.
For some, the discomfort fades quickly. For others, it can be so sore, persistent, and disruptive that you feel like stopping exercise altogether.
Here’s the good news: it doesn’t have to stay that way.
We’ve teamed up with dermatologist Dr. Susan Nedorost to bring you practical, science-backed answers and solutions. In this guide, you’ll:
Understand the main triggers of itchy skin during and after exercise
Learn quick relief strategies that help you move with comfort and confidence again
Discover how simply switching fabrics can make the biggest difference
Why Does My Skin Itch When I Exercise?
Runner’s itch: often used by athletes to describe a prickly, itchy, or stinging feeling that shows up during exercise. It isn’t a medical term, but symptoms can overlap with certain types of hives (urticarias) triggered by exercise, like cholinergic urticaria.
Other triggers: for many, flare-ups are more persistent and disruptive. Often linked to:
Fabrics and dyes
Sweat buildup
Friction or chafing
Sensitive skin & dermatitis: these conditions can make reactions more severe and longer-lasting.
Did you know? Up to 70% of people report* having sensitive skin, and exercise can be one of the biggest triggers**.
A common phrase athletes use for that prickly, itchy, or stinging feeling that pops up during a workout
It’s not a medical term, but the symptoms often overlap with certain forms of hives (urticarias), such as cholinergic urticaria
Cholinergic urticaria:
is triggered when the body heats up and starts sweating e.g. during exercise, hot baths, or even stress
shows up as small, red, itchy bumps (welts) that can sting or burn
caused by histamine release, when skin cells called mast cells release a chemical that makes blood vessels widen and nerves react
usually passes quickly, often within about an hour once you cool down.
Irritant dermatitis (irritant eczema):
Also called chafing or chapping
Happens when moisture and friction break down the skin barrier
Common in moist areas where skin or fabric rubs during workouts
Allergic contact dermatitis (allergic eczema):
Caused by dyes or chemicals in fabrics, or other personal care products
Sweat leaches dyes out of fabrics and makes allergens more available to the skin
Diagnosed with patch testing; symptoms won’t resolve unless the trigger is avoided
Atopic dermatitis (atopic eczema):
A long-term skin condition that can flare in different ways
Triggers may include skin irritants, allergic reactions, or sometimes even foods or medications
Many people with eczema are also sensitive to natural microbes on the skin, like certain types of yeast and bacteria, which can make flare-ups worse
Itchy Skin During and After Exercise: 3 Causes Explained by Dr. Nedorost
1. Fabrics and Dyes
Clothing allergy is one of the most overlooked causes of prolonged rashes - and activewear is no exception.
Nearly 90% of clothing is treated with synthetic dyes. Common activewear fabrics like polyester and nylon don’t absorb dyes well. To hold color, they’re often processed with disperse dyes - some of the worst culprits for allergy!
Dr. Nedorost notes that heat and sweat can also make things worse:
“Sweat promotes leaching of the dye from the fabric onto the skin, which can cause an itchy rash that may last days to weeks after a single exposure.”
Meanwhile, fibers containing chambers (TENCEL™ Lyocell, cotton, rayon, linen, wool) absorb dyes more effectively because of their "chambers" or porous structure. That means they can be dyed with dyes less likely to cause allergy.
“The majority of dye allergy occurs from darkly dyed synthetic fibers without chambers such as polyester, nylon, acetate, or spandex,” says Dr. Nedorost.
Pro tip: Choose activewear that’s independently certified (e.g., OEKO-TEX® Standard 100). This way, you know both the dyes used are safe for your skin.
2. Sweat Buildup
Sweating is a normal part of exercise, and it’s usually beneficial for your skin.
Sweat contains natural moisturizers like urea and sodium lactate that keep the skin hydrated. It also carries antimicrobial peptides that help defend against harmful bacteria and allergens.
For people with sensitive skin or eczema, sweat can quickly flip from friend to foe if it is retained under occlusion (where skin is covered so sweat can’t escape) from garments or gloves that don’t allow air to circulate. Dr. Nedorost explains that:
“You’re more likely to have certain yeast and staph bacteria forming biofilms that cause itchy skin and are increased by moisture from occlusion.”
Other reasons sweat can trigger flare-ups include:
Salt, lactate, and urea can sting and trigger flare-ups in eczema-prone skin. The National Eczema Association states sweaty workouts can “dry out” the skin with sodium, causing further dehydration and irritation.
Occlusion slows the evaporation of sweat which worsens eczema.
People with eczema often lack enough claudin-3, a protein that normally keeps sweat on the surface of the skin. Without it, sweat seeps into the deeper layers, sparking inflammation and itch.
The wrong fabrics can also add fuel to the fire. As Dr. Nedorost notes: “Plant-derived fibers contain air-filled chambers that wick moisture from the skin. Many synthetic fabrics […] do not, leading to irritation from build-up of moisture.”
Pro tip: Shower straight after workouts to clear sweat. Skip dense, non-breathable synthetics like polyester that trap moisture.
3. Repeated Friction
Chafing is one of the most common workout skin struggles. It happens when skin rubs against skin or fabric - especially in endurance sports like cycling and running.
Over time, friction can wear down the skin’s barrier, leaving it raw, red, and stinging. In severe cases, it can blister or bleed. Dr. Nedorost explains that:
“In people with a history of childhood onset dermatitis in skin folds [like inside the elbow and behind the knee], friction from movement causes dermatitis more easily [...] Irritant dermatitis or irritant eczema can also be called chafing or chapping and is often due to a combination of moisture and friction.”
Pro tips to prevent chafing:
Skip fabrics that trap heat and sweat or feel rough on the skin
Avoid heavy moisturizers before workouts; use a light absorbent powder instead
Pick breathable, moisture-wicking fibers that glide over skin (e.g., fine merino wool or TENCEL™ Lyocell)
Reduce skin-on-skin rubbing with form-fitting activewear (e.g., opt for fitted running shorts instead of loose ones)
How to Tell If Your Activewear Is Making You Itch
Step 1: Patch Test
Dr. Nedorost recommends dermatologist-led patch testing as the gold standard. Small amounts of potential allergens are placed on the skin for 48 hours, then checked for reactions over the next 3-7 days.
Step 2: Try a Fabric Trial
No access to patch testing? Dr. Nedorost suggests this DIY method instead:
Wear white garments (any fiber) or undyed fabrics with chambers (cotton, rayon, TENCEL™ Lyocell, merino wool) for 4 weeks
Any outer layers like jackets, can be made of anything as long as you're not sweating or getting wet. Dry garments are unlikely to leach chemicals through another layer of fabric.
Step 3: Look Beyond Clothing
If dermatitis continues, the trigger may not be your clothes alone. Moisturizers, sunscreens, shampoos, cosmetics, and even topical medications can trigger flare-ups.
You won’t likely see your skin improving unless all allergens are identified and avoided. A dermatologist specializing in contact dermatitis can help you identify your allergens with patch testing.
Why Clothing Allergies Are Often Missed
Clothing-related skin allergies are more common than you might think - but they’re often overlooked or misdiagnosed. Here’s why:
Delayed reactions
Symptoms don’t always show up right away.
“Contact allergy to clothing, as well as to personal care products [...] is often overlooked because it is a delayed-type reaction. Contact with something that will cause a severe allergic reaction will cause no immediate discomfort. In the U.S., poison ivy is a familiar example of a delayed type allergic reaction to a plant,” says Dr. Nedorost.
Even a short 5-minute exposure can trigger rashes that last up to 4 weeks. Because of this delay, it’s easy to miss the real cause.
Limited access to testing
Diagnosis requires patch testing, but this isn’t widely available. Without it, people are often prescribed systemic medications instead of simply avoiding the allergen.
Hidden dyes and finishes
Unlike skincare, clothing labels don’t list all the dyes and finishes used. This makes it harder to trace what’s causing your irritated skin.
The good news? Certifications can help.
“OEKO-TEX labelling Standard 100 certifies that no high-risk dyes were used on a fabric. It is helpful and could be even more useful for patients if there were a way to search the internet for retail products with OEKO-TEX certification,” notes Dr. Nedorost.
Best (and Worst) Workout Fabrics for Sensitive Skin
Fabric
Breathable/ moisture wicking
Odor-Resistant/ Antimicrobial
Thermoregulating/ Cooling
Soft/ friction free
Sensitive Skin Rating
Synthetic fibers (polyester, nylon, spandex)
✗
✗
✗
⚠
🔴 Avoid
Cotton
✓
✗
✓
✓
🟠 Proceed with caution
Regular Wool
⚠
✓
✓
✗
🟠 Proceed with caution
Merino Wool
✓
✓
✓
✓
🟢 Best choice
TENCEL™ Lyocell
✓
✓
✓
✓
🟢 Best choice
Bamboo (Rayon)
✓
⚠
✓
✓
🟠 Proceed with caution
🔴 Avoid: not suitable for sensitive skin 🟠 Proceed with caution: may cause irritation depending on activity 🟢 Best choice: recommended for exercising with sensitive skin
Why We Chose TENCEL™ Lyocell for Tripulse
Tripulse specializes in TENCEL™ Lyocell activewear certified by OEKO-TEX® STANDARD 100 for sensitive skin.
At Tripulse, we've spent years working with athletes and experts to understand why traditional activewear triggers itching, rashes, and flare-ups. What we discovered led us to completely rethink how workout clothes should be made - starting with the fabrics themselves.
After extensive research and testing, our choice was clear. Here's why TENCEL™ Lyocell outperforms other popular fabric options:
vs. Cotton:
Gentle on the skin but can cling on to moisture and odors. Ideal for loungewear but not as high-performing for workouts. TENCEL™ Lyocell offers 50% better moisture management, keeping your skin dry and comfortable. If you opt for cotton, choose GOTS-certified organic cotton for stronger health and sustainability standards.
vs. Wool:
Wool can vary a lot in quality. Some types are rough and irritating for people with sensitive skin, while some types of superfine merino can feel softer. TENCEL™ Lyocell is loved for its softness and anti-irritation properties. At Tripulse, we use carefully tested, premium-grade TENCEL™ Lyocell by Lenzing, chosen for its proven softness and fully transparent, ethical supply chain. This isn’t always the case with merino wool sourcing.
vs. Other Wood-Based Fabrics (Bamboo Viscose, Rayon):
The FTC confirms bamboo fabric can lose its natural antibacterial properties during harsh chemical processing. In contrast, TENCEL™ Lyocell retains its antimicrobial properties. Many of our customers report wearing TENCEL™ activewear multiple times before washing with no odor or irritation. Plus, it uses a closed-loop process with only one non-toxic organic solvent.
Vs Synthetic Fabrics (e.g., Polyester):
No contest. TENCEL™ Lyocell outperforms synthetics when it comes to breathability, moisture control, antibacterial, skin-safe and toxin-free properties.
Important: Even natural fibers can be treated with harsh dyes and finishes if unregulated. Always choose fabrics certified skin-safe by trusted independent certifications such as OEKO-TEX®, GOTS, REACH, or Bluesign.
Some activewear - like leggings and sports bras - needs stretch to perform. Yet conventional spandex (or elastane) is a common trigger for skin irritation. This is mainly due to the harsh chemical treatments used.
If you have sensitive skin, we recommend opting for natural fiber activewear blended with healthier alternatives like Roica® V550 and EF. Both are OEKO-TEX® Standard 100 and Cradle to Cradle™ certified with a Material Health Gold rating. This means they’ve been thoroughly tested to be skin-safe.
We spoke with members of the Tripulse community living with sensitive skin. Their stories showed just how much fabrics can impact wellbeing and performance.
What we heard again and again:
Disruptive symptoms. Itching, burning, and rashes often flared up during or after workouts, especially where sweat got trapped in activewear.
Impact on movement and confidence. Many cut back on activities they loved, felt self-conscious about their skin. Some had to take off their activewear straight after exercise to avoid flare-ups.
Relief after switching fabrics. Moving from synthetics like polyester and nylon to TENCEL™ Lyocell from Tripulse made a real difference. Some felt relief immediately, others within weeks.
Compared with other fabrics. Cotton felt too damp and heavy, while merino wool could still itch. TENCEL™ Lyocell stood out as softer, cooler, and higher-performing for sensitive skin.
A lasting transformation. Tripulse’s TENCEL™ Lyocell activewear felt soft, breathable, and cooling. Irritation disappeared, confidence returned, and workouts and daily movement became enjoyable again.
“Tripulse has restored the feeling of being supported, confident, and comfortable in my clothing without my sensitive skin being irritated in the process.”
Yes. Sweat can sting, dry out, and inflame eczema-prone skin. Extra moisture often fuels bacteria and yeast, which can cause further irritation.
Is it ok to exercise with eczema?
You can absolutely exercise if you have eczema. You don’t need to give up movement, but you may need to adapt.
If you struggle with eczema when you exercise:
Keep workouts cool and low-impact when you start to notice eczema symptoms
Shower promptly after activity
Use light powders instead of heavy moisturizers in sweaty areas
Opt for activewear made from naturally breathable, moisture-wicking fabrics like TENCEL™ Lyocell and superfine merino wool to reduce friction and flare-up.
With the right strategies, eczema and exercise can go hand in hand.
How do I know if I am allergic to polyester?
Allergic contact dermatitis to textiles in the modern era happens when you become allergic to dyes. Dye allergy is more common in synthetic fabrics, but can also occur in fabric blends used in socks, etc. Exercise can make textile allergy worse because sweat leaches dyes out of fabrics. Also, since polyester fibers trap sweat, they worsen pre-existing eczema.
Pro tip: Many of our customers with sensitive skin have found switching from polyester to TENCEL™ Lyocell activewear a game-changer for workouts and everyday wear.
Consider patch testing if symptoms persist beyond 4 weeks
Remember: sensitive skin doesn’t mean you have to stop moving. Start with one small change today. If you're ready to try activewear designed specifically for sensitive skin, we're here to help.
Medical Review Process: This content has been medically reviewed by Dr. Susan Nedorost, MD, FAAD, Thank you, Dr. Nedorost, for your meaningful contributions. Last reviewed: 18 Sept 2025.
Disclosure: This article is for informational purposes only and does not replace medical advice. If you have a skin condition, are unsure about your symptoms, or experience severe reactions, always seek guidance from a qualified healthcare professional. Dr. Nedorost serves as an independent medical reviewer and has no financial relationship with Tripulse.
About the Author
This article is written in collaboration with Christie Johnson (B.A. Hons, PGCert), a health and sustainability writer with over five years of experience writing in the conscious fashion space. She explores how the clothes we wear affect our skin, well-being, and the planet - translating complex ideas into clear, empowering insights. With a strong foundation in clean materials and non-toxic living, Christie's work is grounded in integrity, curiosity, and a deep care for people and the world we share.
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