Red welts from shorts

[maryellen]

Something similar happened to me a few years ago when I was riding a lot training for an aids ride. All of a sudden, when I took my bike shorts off I would have red welts -- though in my case they were all over my butt and thighs. Didn't hurt, weren't uncomfortable. Hadn't gotten new shorts. Hadn't changed laundry detergent. Just a mystery.

I handled it by taking off my bike shorts as soon as I returned home and got in the shower as soon as possible. The problem seemed to subside when the weather got cooler and hasn't happened since.

[Eden]

Could be just the type of ride you did? I had a pair of shorts last year that were fine for shorter and dry rides, but put them on for a long ride or a wet one and they'd lacerate my poor backside.... something about the stitching on the chamois acted like a little saw blade - left the darndest marks on my hienie - looked like I'd been bitten by a shark and it was none too comfortable either. Slathering the stitching up with chamios butter didn't help either.

[easterbird]

Thanks for comments. I am somewhat surprised that this seems to be a rather unheard of malady. I think I may have started this process by going riding,sweating a great deal, getting distracted by chores and not changing asap when I came in the first time. However, I felt the second batch of welts forming(worst on my left cheek) part way into the 79 mi ride on Sunday. I am speculating it was partly the sweat and partly me pedaling weird on that side? Maybe? anyway I could defineitely feel the welts(looks like I was scratched or whipped??) when I rode today. It is where butt and seat collide. Different shorts and lots of butter before I started. Did 40 with 2000' climbing and no new welts. Today was hotter than blazes in Pa. If I discover the root cause, I'll post again. thanks

[BleeckerSt_Girl]

Another thing I got recently which might apply to you:

About a month ago, it was quite cool and very sunny one day when we were going for a long 50 mile ride.
So I put some knee length Terry knickers on with a very thin chamois, then I pulled some regular bike shorts on over that to give myself enough padding for the ride. The knickers ended at the knee, the shorts ended half way down my thigh. I put sunscreen on my exposed legs below the knee.
After the 5 hour ride, took off clothes and saw a big red raised rash on the tops of my thighs- but the rash ended abruptly right at the line where the shorts started. No rash at all underneath the double layer. I decided the rash was a sun allergy reaction under the knickers, right where I got the most sun, on the tops of my thighs. I didn't really sunburn through the fabric, but the sun + fabric caused a rash reaction somehow. I put hydrocortisone cream on it and it faded after a couple of days. It flared up again a bit when I went in the sun with just shorts on a few days later. Now it seems to be all gone. But as a precaution for a while, I put a bit of sunscreen on that area of my legs, under my knickers when I was going for really long rides. Don't seem to have the problem now.