I've had psoriasis my whole life, head to toe, including nails. Changing my diet to natural, vegan and gluten-free cleared everything in about 3 months. I was shocked, couldn't believe it. That was in 2019, and I couldn't stick to that lifestyle change, so my psoriasis is back.
Obviously our bodies all differ from one another, and you might not respond the way I did. The nails did take the longest to clear. But it's something to try if you haven't done so before.