tarwheel 

I've been developing a heat rash on the tops of my thighs after long rides, particularly in hot weather. It's been happening for a while but has been getting worse. I initially thought it was due to silicone sensitivity due to the leg grippers on my shorts, but the rash still develops when I wear shorts without the grippers. Usually my legs don't break out unless I ride 50 miles or more, but the rash was worse than ever after riding 38 miles on Sunday during extremely hot and humid weather. My thighs looked like I had poison ivy after the ride.

Does anyone have any suggestions for preventing or treating the rash? After reading up about heat rash, it seems that the best way to prevent is to provide plenty of ventilation. Unfortunately, strenuous exercise in hot, humid weather seems to be a key contributor to the problem, but I am not going to quit going on long rides. I am certain that tight-fitting bike shorts are another factor, so it seems like my best option is to looking into getting some shorts that are looser fitting and more ventilated.

Machka 

Are you using sunscreen on your legs?
I found that I had to use a "for sensitive skin" sunscreen or I would develop the same thing.


My shorts didn't help either ... especially any with lycra, spandex, or nylon in the materials list. If they were blended with cotton or polyester, they were some better. And sometimes I cycled in basketball shorts or beach shorts.


I found IBUprofen and ice packs helped after the ride.


But yes, it was very frustrating!! I haven't experienced it in some time because I haven't been in a place where it has been warm enough for that in years.

10 Wheels

Diabetics get that

Machka 

I rather doubt that's the problem ... certainly wasn't for me. Lots of people get heat rashes.

tarwheel 

I've suspected that sun screen might acerbate the problem, but I need sun protection around here. Heat rash is better than skin cancer. However, that's a good idea to find some sun screen for sensitive skin.

I don't think it's diabetes. I get annual physicals and my blood sugar levels are normal.

pdlamb

After your post-ride shower, treat heat rash with Anti-Monkey Butt Powder: https://www.amazon.com/Anti-Monkey-B.../dp/B002HW5AT0.


Yeah, there's other powders that will probably work just as well, but how can you pass up using a product with a name like that?!

Machka 

I use this:

https://www.neutrogena.com.au/our-pr...y-lotion-spf30

I find the following features are beneficial ...

*High Protection SPF30+
*4 Hours water resistant
*Non comedogenic (won't clog pores)
*Oil free

But there are likely other similar products out there too.

zonatandem

Try switching to another detergent when you wash your shorts . . . it *may* help.

9606

I get same condition.
Just ordered some Sugoi leg sun sleeves.

tarwheel 

I use "free and clear" laundry detergent that doesn't have any scents or other additives, so I don't think that's the issue.

I will try some of Neutrogena sunscreen. I've had good results with their other products.

berner

I was having the same problem, first with a particular pair of shorts and then with a particular pair of socks. It did not seem to be related to heat because I get rid of those items and the rash stopped also. I've also found I need to use unscented laundry and bath soap. I suspect that as we age, our bodies develop allergies to some of the chemicals used in manufacturing.

tarwheel 

I did an experiment today and rode 2:45 hours in the heat with no sunscreen on my thighs. Guess what? No heat rash at all, even wearing shorts with silicone grippers. So apparently I was having a reaction to the Coppertone sport sunscreen I've been using for a long time. Guess I better go shopping for a different brand.

Good call, @Machka

2manybikes

Is the 2:45 hour ride about the same duration you were riding before ?

tarwheel 

Comparable. The rash has tended to be the worst on long rides in hot weather. Today was one of the hottest days of this summer, with heat index close to 110. I rode 44 miles today, about 6 more than last Sunday, when the rash was so bad. However, the ride was slower last week and I was out in the heat longer.

Machka 

When I went searching for a solution, I discovered the same thing. It was the sunscreen! I had been using just some inexpensive brand I happened to pick up and evidently the mixture it with my sweat and all heated up by the sun was not good at all.

tarwheel 

I picked up some Neutrogena sunscreen and have used it now on several long rides in very hot humid weather. No rash whatsoever, so my previous sunscreen must have been the problem. I've also had a milder rash in spots on my face for a while and have been to see my regular doctor and dermatologist about it. Despite trying several different treatments, nothing got rid of it. Apparently my old sunscreen was causing that rash too, because it's gone away now that I quit using it.

That got me really curious, so I was reading the ingredients in Coppertone Sport sunscreen and it contains aluminum. A long time ago I had to stop using most regular deodorants, which often contain alumninum, because they caused a rash in my arm pits. So apparently I am allergic or have a sensitivity to aluminum.

CherylH

Peadslonenjoy

It's the sunscreen and the nylon, use a mineral based sunscreen with zinc and you should be good to go. I had the same problem.