THE MODIFIED RODNAN SKIN SCORE IS AN ACCURATE REFLECTION OF SKIN BIOPSY THICKNESS IN SYSTEMIC-SCLEROSIS

Objective. To test the ability of the modified Rodnan skin score to re flect skin thickness in skin biopsies from 141 patients with systemic sclerosis (SSc) obtained at entry during a prospective, double blind s tudy of ketanserin versus placebo in SSc. Methods. Punch skin biopsies (4 mm) were obtained from the dorsal surface of the distal forearm of 141 patients. Biopsy specimens were trimmed and weighed (wet weight) and then desiccated and reweighed (dry weight). Skin score was recorde d for 17 areas, graded 0-4+, while edema was graded 0-4+ in 10 of the same sites using finger pressure. Results. Total skin score correlated with wet weight (r = 0.553) and dry weight (r = 0.517) of the skin bi opsies. Local skin score from the biopsied forearm also correlated wit h wet and dry weight (r = 0.536 and 0.530, respectively). Dry weight a s a percentage of wet weight was the same for diffuse cutaneous SSc (d SSc) and limited cutaneous SSc (lSSc) (30.7% for both, NS), despite in creased wet weight in patients with dSSc versus lSSc (17.75 vs 13.03 g ; p < 0.001). Edema scores correlated poorly both with wet weight (r = 0.069) and dry weight (r = 0.169). Conclusion. Total and forearm skin score correlates well with both wet and dry forearm skin biopsy weigh t from forearm biopsies, indicating that skin score reflects the under lying pathology of SSc. Further, the percentage of dry to wet weight i s similar for lSSc and dSSc, supporting the usefulness of skin score i n differentiating SSc disease subtypes.