I have psoriasis. Can I use minoxidil on my face?

Minoxidil doesn't work for beard growth for everyone, but if you have psoriasis and plan to use it, you may want to use it under monitoring of a dermatologist. It's unlikely to flare as I often use minoxidil for treatment patients with psoriasis who have male pattern balding. But you are right. Anything that irritates could trigger a flare. Use cautiously under care of your doctor and if you flare you'll have a plan to stop the flare quickly.

You should be asking this question to your doctor. The management of psoriasis is a complex problem and should not be handled by an amateur.