I have scalp psoriasis. Can I use Minoxidil for hair regrowth?

You  have a combination of  medications and conditions that needs monitoring by a dermatologist who is a hair loss expert. Psoriasis is an inflammatory process that can negatively affect your hair loss. It needs to be treated. Homeopathy is not adequate as a psoriatic remedy. Furthermore,  psoriasis can increase the irritation and absorption of minoxidil. Minoxidil can inflame psoriasis. PRP does have anti-inflammatory properties and can regrow hair in some patients and improve scalp irritation. In my opinion, I would consider switching from topical minoxidil to oral minoxidil as it will have less of an effect on your psoriatic scalp and inflammation. Use standard allopathic treatments administered by a dermatologist to improve your scalp  psoriasis. 

Provided you are under care of a physician who is knowledgeable about both psoriasis and hair loss and side effects of minoxidil it is possible. Minoxdil can irritate the scalp of some patients with psoriasis and minoxidil absorption can also be increased in those with scalp psoriasis. You are using a non approved off label dose of minoxidil which requires careful monitoring to esnure side effects like headaches, dizziness, chest pain, heart palpitations, ankle swelling do not occur. Keep close follow up with your specialist to monitor both your psoriasis and your hair loss.

You are clearly being treated by a doctor so I would follow that doctors advice with the use of minoxidil