Am I allergic to biking? Help!

[GLC1968]

OK, this is very odd and I'm hoping I'm not alone so that someone can offer up some clue as to what I am dealing with here. This is not a TMI type post, by the way!

A little background info: I started riding a year ago. I live in the south, so riding in temps over 90 degrees is common. I have no alergies and I do not have sensitive skin. I always slather on the sunscreen when I ride and I've used multiple different brands. I noticed that I developed this unusual rash last year after my first long ride (65+ miles).

I get this red lumpy rash on the front of my thighs when I ride longer rides (50+ miles). It looks like bad welts (as if I scratched the hell out of a rash of some sort) on my legs at the end of the ride, but it goes down to just red splotches in the days following. It lasts about 3 or 4 days. It does not itch or hurt or burn or anything. It's very ugly, but I don't feel it at all (though it is normally warmer to the touch than the rest of my leg). Its only on the front near where my shorts end, but it doesn't matter which shorts I wear or which length they are (some cover the rash, some bisect it, and some are shorter than it).

Does anyone have any ideas? Oh, and it has progressively gotten worse (but our rides have progressively gotten longer so I don't know if that's why or not)...

If you've gotten this far, thanks for reading. Now help me!

[Kimmyt]

I think you should talk to a Dermatologist!

[FreshNewbie]

you might have sensitive skin and combination of sunscreen, sweat and shorts irritates it. I would suggest going to dermatologist to see if it's an allergy or something else.

[GLC1968]

I've thought about seeing a derm about it, but the problem is that the rash doesn't stick around in it's orignal form all that long. I'd need a doc to work on a weekend and that certainly isn't going to happen.

My shorter weekday rides don't trigger it...even if I ride before the redness has totally gone away.

I think I need to befriend a derm and then ride with them so that they can see it when it's new!

[Lenusik]

I've thought about seeing a derm about it, but the problem is that the rash doesn't stick around in it's orignal form all that long. I'd need a doc to work on a weekend and that certainly isn't going to happen.

This might be a crazy idea, but I would make an derm appointment first, let's say for Monday. And then ride your long miles on Sunday. You can certainly take a picture but there is nothing better then a real test. I am sorry for giving you a suggestion to suffer, but at least your doc would be able to test you for allergies or poison ivy.

[Geonz]

I get a rash, same place, though doesn't sound like it's as bad. I noticed it happened *under* those nifty Zoic knickers, so it wasn't sun (thought maybe the shorts rubbed off the sunscreen or something). It'll stick around for a couple days though it fades.
Yea, I would make a Monday appt and ride a long one on Sunday (tho' I might try shorts rinsed nicely in something hypoallergenic first).

[TsPoet]

It doesn't sound like EIA, but I thought I'd throw it out there. About 10% of the people who have Exercise Induced Allergy (or Asthma) get hives/rashes. I am part of that 10%.
My hives are all over, not just in one area, so I don't think that applies, but it's something to check out. I also only get the breathing problems when the temperature outside is either hotter or colder than what my body is used to that day.

[Fredwina]

All your shorts the same (brand/Chamois)? If not , is the rash worse with some?

[tprevost]

sounds like it could be a form of heat rash... have you tried some cortizone cream on it?

[withm]

That sounds like the same rash I get if I use a sunscreen with PABA in it. Doesn't hurt, itch, just looks really bad.

Try a sunscreen w/o PABA. (I use Coppertone Sport something - blue bottle. sweatproof, comes in SPF 50, no problems with that one.) A lot of people are allergic to PABA (whatever that is).

[bcipam]

Where exactly is the rash? Under or below the short line? If under your shorts, it could be a combination of sweat and laundry detergent causing contact dermatitis. I had the same problem. I cannot use power laundry soap, only liquid.

If below the shorts, is it possible your legs are rubbing up against something? Again it's probably conatct dermatitis - you just need to figure out what is the irritant.

Also what is the material of your shorts? Does it include cotton? Microfiber? what? This may also be the problem.

[Aint Doody]

GLC, I have it, too. Usually just in the first couple of long rides in the season when it's sunny. I've been thinking it's a heat rash. One of my cycling friends has it, too. I don't think it's a contact dermititis--like you said--it doesn't matter if the shorts are long or short. It's always in the same place. Funny, though, I never feel like the tops of my legs feel any hotter than anywhere else.

We'll have to call it "Ugly, strange, cycling rash!"