So, it's my turn. Last Sunday I rode about 68 miles on a hot sunny day. It was a long, slow ride with various stops for mechanical issues and missed turns as well as scheduled rest stops. Later that day I noticed some red, slightly puffy blotches on my legs, just below the where my shorts ended and just above my knees. At first I thought it was sunburn, but it didn't hurt. It didn't itch, either.

Today (Saturday) I did a 62-mile ride. It was not quite as hot, and though the sky was blue for most of the ride there were a fair number of clouds in the sky to keep the temps in the 80s, below average for July in the DC area. And after the ride I noticed the same red, slightly puffy blotches just below where my shorts ended.

Based on my extensive experience with contact dermatitis, I do not think this is a sunscreen allergy. If it was, I would be covered in an itchy rash, especially on my face.

But -- I also have a history of mystery hives, which my doctor has diagnosed as autoimmune hives. Most commonly this manifests as small red bumps that itch like crazy at first and then slowly fade over several days. Sometimes it is worse than that, with wheals that look like classic hives or angioedema. Anyway I started to experience a flare-up 2 days before the bike ride last Sunday, with small itchy red bumps that mostly have occurred above and below my knees.

So my first thought is that the red puffy blotches are related to the extra histamines that are in my system right now.

I started taking an antihistamine (Zyrtec) every day back in January, and this is the first time since then that I've seen more than an occasional random red itchy bump. Today I stopped at the store to get some Zantac, which is an H2 inhibitor, and I will start taking that to see if it helps the Zyrtec beat down this particular episode. I'm hoping that once these hives fade away then the red puffy patches will also stop appearing.