PTH and alopecia areata: For non-inflammatory autoimmune skin diseases (such as vitiligo or alopecia areata), in general, a lower vitamin D3 dose appears to be sufficient for a good clinical response (drop of PTH levels in patients with vitiligo: baseline vs. >365 days p < 0.001, non-vitiligo patients: baseline vs. >365 days p < 0.001), as has been suggested elsewhere [16,19].