My son is 9 and has had Alopecia universis for 3 years. It started with spots and elevated to 90% hair loss. He is vegan and have consulted 2 doctors. We have changed diet to remove most processed foods and 5 months ago removed gluten. his hair began to regrow and then stopped and now is thinning again. What is the next step?

Summarized question: How to treat chronic alopecia universalis?