Use of a durometer to assess skin hardness

Abstract

Skin induration is difficult to quantify. In patients with systemic sclerosis (scleroderma), a clinical skin severity score (0 = normal skin; 3 = maximal induration) has been in use for several years for assessment of skin involvement and therapeutic outcome. The purpose of this study was to find a more objective method to assess skin hardness in patients with scleroderma. Finger pads, forearms, and thighs of 12 sequential nonselected patients with scleroderma and eight normal control subjects were scored by an observer blinded as to group, and quadruplicate determinations of the degree of skin induration at these anatomic sites were made with a hand-held type O durometer. Consistently, these anatomic sites except for the forehead showed a direct relation between the skin severity score and the hardness measured with the durometer. The best results were obtained from the index finger pad where, compared with uninvolved skin, an increased skin severity score was associated with higher durometer readings (p = 0.0032, p = 0.0002, and p = 0.0005 for skin scores of 1, 2, and 3, respectively). The durometer is an effective and reliable method to assess skin hardness.