When you do research there are several versions of screening tests for psoriatic arthritis. You answer the questions and evolve a point total that suggests you have the diagnosis.
My results were positive and yet my first rheumatologist
gaslighted me as my psoriasis was so mild and controlled
with minimal involvement of my scalp and nails on steroids.
My present university rheumatologist did a very thorough
consult with ultrasound to make the right diagnosis.
There is no specific bloodwork for PsA but it helps exclude
other conditions.
The antibody medications for psoriatic arthritis improve your skin as well. The type of psoriasis flare caused by strep infections
is termed guttate psoriasis and could be mistaken for dermatitis. Hope your new rheumatologist gets you on a disease modifying drug. I would consider finding a dermatologist more interested in your case.
They will likely reassess your lupus antibodies but the facial
rash may be dermatitis related to the body eruption.
Psoriatic arthritis affects our bodies as a form of inflammation that needs ongoing management.
You have a good support community here and we are interested in your progress.

For self education go to dermnetnz.org which has one of the best skin conditon sites on the internet.