My premature grey hair was from vitamin B12 deficiency (in my case due to autoimmune pernicious anaemia) which reversed when I corrected my B12 deficiency. I also have vitiligo, Hashimoto's thyroiditis and alopecia areta.
There was a time I was VERY hyperthyroid but my labs were showing hypo because I was in a state of Hashitoxicosis (Graves antibodies in this particular instance since leakage symptoms of Hashimoto's thyroiditis is mild in comparison - you can check the link below on another answer of mine about Hashitoxicosis). The only lab showed I was hyperthyroid at the time was the thyroglobulin serum test (which was high due to being hyperthyroid).
Excerpt from Bel Mara Health - Vitiligo linked to simultaneously existing autoimmune diseases...
"Vitiligo, an autoimmune skin condition, is linked to simultaneously existing autoimmune diseases. Researchers from St. Luke’s-Roosevelt Hospital Center created a questionnaire to be answered by children and adults who had vitiligo to determine other coexisting autoimmune diseases, which may appear along vitiligo.
Based on the survey results, the most common vitiligo-associated autoimmune diseases (VAAD) were hyperthyroidism and hypothyroidism, rheumatoid arthritis, pernicious anemia, type 2 diabetes, alopecia areata, psoriasis, chronic urticaria, type 1 diabetes, ulcerative colitis, celiac disease, Sjögren’s syndrome, Raynaud’s disease, lupus, sarcoid, Crohn’s disease, dermatitis herpetiformis, Addison’s disease, and multiple sclerosis.
In an alternative study conducted by researcher Iltefat Hamzavi, other VAAD found in the participants of his study also included linear morphea, Guilllain-Barré syndrome, and myasthenia gravis, along with the conditions listed in the previous study."