What is this rash? (with pictures!)

In My Humble Opinion
1

I’ve been riding my bicycle a lot, and whenever the temperature gets over about 90 degrees my legs start breaking out in a rash. The worst is on the tops of my thighs, but I will also get it on my calves and ankles. It’s red, puffy, and very sensitive. It extends about 3 inches above and below where my bike shorts hit on my leg.

Ignore the gnarly tan line :stuck_out_tongue:
Pic 1
Pic 2

I’ve tried using different sun screen and different bike shorts, but the only thing that seems to make a difference is the temperature outside.

Any ideas on what I can do to prevent it or treat it?

2

Looks like urticaria, aka hives. Some common causes are heat, moisture, irritation, excercise, etc. It’s an allergic reaction, but not always caused by allergens. I used to get them years ago on clothing contact points when exercising. The thing I found most helpful was putting a lotion containing dimethicone on those areas before working out, but it still didnt totally prevent it.

3

Dang, Speak, looks like that’s what it is. Next time, could you diagnose me with something easier to treat? :stuck_out_tongue:

4

You might try switching laundry products. I get hives around the underwear waistband from fabric softener dryer sheets.

5

Turble, I considered that but I don’t use dyer sheets or fabric softener on my workout clothes. They air dry and I already use a hypoallergenic laundry soap.

6

Try shorts without the elastic cuffs, or roll the elastic up over the lyrca a bit to see if it makes a difference?

7

I vote for the laundry products. I switched to dash or all or even a baby diaper laundry soap. I think it has more to do with caustics than allergens.

8

I used get something a little like that sometimes - contributing factors seem to be sun exposure (not always heat) and sunscreen - it’s only ever where the sun hits my skin - gets really hot and itchy, and it’s not sunburn.

From what I’ve read some sunscreens contain chemicals that can cause photosensitivity and a rash when exposed to the sun. I changed my sunscreen to a more physical block and it’s been a few years since I last had it. Can’t be sure it’s the same thing, but could be worth considering.

9

I’m allergic to all sunscreen and get hives just like that if I use it.

10

I don’t think it’s caused by the laundry soap since it’s just on my legs, but I went ahead and bought some “all” brand to try on my workout clothes. We’ll see if it makes any difference this weekend!