Suggest Treatment For Itchy Scalp And Hair Loss

My son has a painful itchy scalp. As it grows it falls out, it appears the follicles can t support the hair and they come out with the white bits attached at the end, often either very small or attached to a larger blockage. He often finds random follicle bits on his scalp like those you d find in a blocked pore. It s not dandruff and his scalp is not dry and flakey. He is a transgender male, is on testosterone, and has been for many years, but this has just come about in the last year. It doesn t matter if he s stressed or calm, happy or depressed. He is not on any other medications and has been to a dermatologist who basically told him it s either due to the testosterone or he s imagining it all. He is very frustrated and still in pain and losing his hair. No one has done any tests. Can you offer any suggestions for us to move forward with?