My Granddaughter Had A Bad Case Of Ringworm Last Spring/summer

My granddaughter had a bad case of ringworm last spring/summer and had a bald spot from it, the hair has since grown back. She and was on some very powerful meds to get rid of it, she has since had thinning hair, and now has a small bald area, the dermatologist said it is not alopecia. Could a weakened immune system cause this problem ? THe DR tested her thyroid and her levels were borderline low. They are going to retest her thyroid in three months, Her hair is growing back, and the dermatologist is concerned that she is pulling or tugging at her hair. My daughter said this started when the ringworm started. She is 12.