Lack of correlation of skin thickness with bone density in patients receiving chronic glucocorticoid.

The objective was to test the hypothesis that there is a correlation between thinning of the skin and bone in patients on chronic oral glucocorticoids (GCs). This was a one-time cross-sectional analysis performed in an academic referral center. The study group consisted of 14 patients on GCs for a variety of disorders, including dermatomyositis, pemphigus vulgaris, pyoderma gangrenosum, and urticarial vasculitis. Skin thickness was compared with that of 24 sex- and age-matched controls. The main outcome measures were the bone density of the lumbar spine (L2-L4) and the skin thickness. The skin thickness (mm, mean +/- SEM) in GC-treated (n = 7) vs unmedicated age-matched Caucasian women (n = 20) was 0.84 +/- 0.04 vs 1.02 +/- 0.04 (t = 3.07, P < 0.01) in the upper arm, 1.13 +/- 0.09 vs 1.49 +/- 0.05 (t = 3.65, P < 0.002) in the dorsal forearm, and 0.96 +/- 0.07 vs 1.17 +/- 0.02 (t = 2.92, P < 0.01) in the ventral forearm. L2-L4 bone densities averaged 106 +/- 2% in the GC-treated female patients relative to the age and sex-matched controls. There was no correlation between skin thickness and bone density. In GC-treated (n = 4) vs unmedicated Caucasian men matched for age (n = 4), skin thickness was 1.09 +/- 0.4 vs 1.33 +/- 0.05 (t = 3.51, P < 0.02) in the upper arm, but was not significantly different at the two forearm sites. No correlation between skin thickness and bone density was observed. The level of type I procollagen mRNA in skin from three GC-treated patients was 45% of the value in three age-matched controls. In conclusion, GCs cause statistically significant thinning of skin independently of the effects on bone.