Blood pooling behind knees?

[outofadream]

Been playing the old game of “POTS or not?”. I noticed this past month that every time I stand up, the creases behind my knees turn a bruised reddish-purple color, and then a flush of red creeps down just the back of both calves and a bit up into the back of the thighs. As soon as I sit down and put my legs up, both the dark crease and redness go away almost immediately
What’s been puzzling me is I don’t see much evidence of blood pooling elsewhere…the front of my legs, ankles, and feet look perfectly fine, no really obvious pooling. Haven’t noticed any obvious changes in POTS symptoms either, although it’s been so unpredictable lately that it’s hard to be sure. The only thing that’s changed (and  not sure if it’s related), is been getting some vague leg pains haven’t had before…burning, tightness, tenderness that comes and goes in various places.
Has anyone here happened to have blood pooling like this? Just trying to get a feel for if this is POTS’ latest trick, or if I’m barking up the wrong tree

[statesof]

I typically for myself have only noticed blood pooling in my hands or feet, especially if I've been standing for a while or showering. But I have not experienced any noticeable pooling other than that.

[Clb75]

I tend to get a mottled red and white appearance on my feet and legs shortly after standing or even when I'm sitting without elevating my feet. This can be common for pots. Dr. Raj wrote an article about this, I don't have the link but you can google "dependent acrocyanosis pots" and his article will pop up along with a picture. Not sure if it's the same thing that's happening with your legs but thought I'd mention it in case you'd like to take a look at the article.  In my case I've found that wearing compression tights and elevating my feet tend to help it. 

[TCP]

Do you sit down a lot with your feet on the floor? 

[outofadream]

I’m sorry it’s taken so ridiculously long, but wanted to make sure you all knew I really appreciated your thoughts on this. Doctor ended up doing doppler to make sure no blood clots (was clean), and concluded that since only happens when I stand up, is probably some kind of POTS shenanigan.
I wonder if it’s because I went through a time where wasn’t able to be up on my feet much, and then started suddenly standing for a much longer time than body had been used to...maybe caused some manner of pooling wasn’t getting before? Compression stockings definitely seem to help, so that’s been good at least. Will finally be seeing one of the POTS doctors on the official list in January, so hopefully he can shed some light, since it’s been kind of a busy year in general for new symptoms popping up unexpectedly.
I really appreciated you guys putting me on the right track though, the link to dependent acrocyanosis was particularly helpful Clb75. I definitely get that kind of pooling too statesof, the old tomato hands problem :/ I don’t sit too often that way TCP because it makes the POTS so surly, but it does seem to cause the leg pooling when I do.
Thank you all again, seriously!