I have psoriasis with various location of lesions. Lately I have developed swelling of both legs.

See a dermatologist and get started on a DMARD such as Methotrexate. It often takes about a month to kick in, but you should see appreciable change.

are you having any problems with your joints?

This sound like you have water retention possibly through the psoriasis. get your doctor to check this out it could be some thing simple and he will discribe water tablets

Hi, I've actually had this happen to me on numerous times and it's becasue my legs were covered completely from knees to ankles. There was fluid retention and i was given water tablets and what i also did which was recommended by my doc was to sleep with my legs ellivated making sure the level was above my heart. I would prop my legs on two pillows at night. Unfortunately as soon as I stood up I felt like all the fluid from my upper body would rush to my legs again. It's takes time to go away but you need rest as well. It's very painful, felt like my skin was about to burst open. but it goes away in some time.