Talk to Endocrinologist on Diffuse Alopecia Areata

Hello! My sis is suffering from diffuse alopecia (full head) from past 13 years. We get treatment , hair regrows like babies hair and then falls again. Now she is getting excimer laser 308 treatment and it was going well but after 6th session hair falling again. But at the same time new hair are coming. Means hair growth and fall at same time till now (8th session ). Whats the possible reason? Is there any other possible treatment in Pakistan? Is hair fall due to some allergy? Any hope that they don't fall again and again.