Correlation of vitamin D and vitamin D receptor expression in patients with alopecia areata: a clinical paradigm.

BACKGROUND: Vitamin D (Vit.D) deficiency has been reported in alopecia areata (AA). Downregulation of Vitamin D receptor (VDR) on hair follicles is associated with reduced hair growth. OBJECTIVE: To correlate serum Vit.D levels with severity, pattern, and duration of AA, and density of VDR expression over hair follicles in AA patients. METHODS: Prospective study including 30 AA patients and 30 healthy controls. Clinical details and serum Vit.D measurement and scalp biopsy for histopathology and VDR expression was performed in patients and controls at baseline and after 6 months of treatment of AA. RESULTS: Mean age of patients and controls was 28.9 ± 9.96 and 31.17 ± 9.43 years, respectively. Mean SALT score in patients was 35.8 ± 27.5 with a median disease duration of 48 weeks. Mean serum Vit.D levels was 7.65 ± 4.50 ng/ml and 15.8 ± 11.47 ng/ml in patients and controls, respectively. Twenty-nine (96.7%) patients were Vit.D deficient (<20 ng/ml), compared to 22 (73.3%) controls (P = 0.001). Serum Vit.D levels inversely correlated with severity of the disease (r = -256), P = 0.17, and duration of disease but did not correlate with pattern of AA and VDR expression in tissue samples. VDR expression was reduced in all patients and was normal in controls. Inverse correlation of VDR was noted with presence of inflammation on histology (P = 0.02). VDR upregulation post treatment was seen only in 13% of patients and demonstrated no correlation with response to treatment. CONCLUSION: Vit.D deficiency in AA correlates inversely with disease severity and duration. VDR expression is reduced in AA and inversely correlate with inflammation histologically but does not correlates with serum Vit.D levels, severity, pattern, or duration of illness.