Flash Rash?

[MikeVanBC]

Hi Folks,

I went for a 3km walk with my wife yesterday wearing a short-sleeve shirt under a waterproof rain jacket that is supposedly breathable. Near the end of our trip I’d removed my jacket and discovered a smooth bright red rash in large patches over most of my now bare arms.

It was moderately itchy but I resisted too much rubbing and sought relief in our life-saving hot tub. Although I feared that may have exacerbated the problem, the rash completely disappeared within minutes.

I’ve googled the heck out of rash searches to no avail but can find no relevant reference. Does anyone have any information or experience with something like this? The rash or flush was a lot like what can happen with a large dose of niacin.

Can PMR and/or the drop from 17.5 to 15mg of prednisone triggered or contributed to this, or do you think the heat trapped in the jacket was the culprit?

The latter seems plausible, but I’ve had far more vigorous events under comparable or less breathable garments in the past without ever triggering such a ‘flash rash’.

Thoughts?

[PMRpro Ambassador]

Had you worn the jacket over bare arms before? Sounds like a reaction to something in or on it.

A lot of people have had problems with developing allergies after developing PMR - and often being on pred masks that until they reduce the dose though it usually at under 10mg that they notice.

[MikeVanBC in reply to PMRpro]

I think I’ve worn that jacket over bare arms before, but I can’t recall for certain. That being said, I certainly perspire more with PMR & pred, so that may have contributed to ‘washing’ more of something off the inside jacket arms. Thanks for your thoughts Pro. I presume you’ve not seen this as a known or potential side effect of our condition.

[PMRpro Ambassador in reply to MikeVanBC]

Just the development of allergies/reactions we haven't had previously. And a few people have reported urticaria developing in the last year or so.

[MikeVanBC in reply to PMRpro]

Thanks. Not hives in this case. No raised bumps and disappeared instantly. I’m chalking it up to something on the jacket fabric unless and until it happens again under different circumstances. Thanks again 🙏

[PMRpro Ambassador in reply to MikeVanBC]

It's certainly what I'd suspect first! Hope it doesn't happen again

[Iloveholidays]

In the past (before pmr) I got red blotches on my legs if swimming in a cold sea, once I’ve warmed up they disappear, perhaps yours is something similar but when getting hot??

[Missus835]

It does sound a bit like urticaria, which my grandson experiences when near the ocean and cold. He cannot expose his skin to anything cold. He does get a rash, sometimes hands swell like a boxing glove. He gets nauseous. Perhaps a reaction to the heat from the jacket. I have PMR and randomly sweat terribly and will heat up like a hot flash (but it's not at 72). I'd also be inclined to think it's your sweat mixing with something in the fabric. Best of luck.