Yeah, I apparently had a herald patch on my back that I hadn’t seen. That is how it starts. The herald patch is the single patch that appears before the general fine rash comes up. So if you had something like that at the start that tracks.

The timing too. (More common in Autumn and Spring. More common in women.)

The fine rash does apparently change to those more circular patches in the next stage. (I don’t remember mine doing that but it was a while back.)

It can definitely spread to upper arms and thighs.

I’m really hoping that’s what this is because it isn’t highly contagious, usually resolves by itself in a few months, and usually doesn’t recur.

I was given cortisone cream to help soothe it but for some reason cortisone cream burns my skin so I just let it resolve on its own. Plain moisturiser might also help if it is this. Avoiding soap is also recommended as it might irritate, and maybe also don’t shower too hot.

https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/pityriasis-rosea#

Definitely make sure it isn’t something else that is infected, contagious or does need treatment though! And there are some things cortisone cream or moisturiser should not be applied to so definitely check with a professional first.