Calculation of nail plate and nail matrix parameters by 20 MHz ultrasound in healthy volunteers and patients with skin disease

Background/aims: The objective, but noninvasive, assessment of the nail pla te and nail matrix is of interest in dermatology, and cosmetics as well. Th ese cutaneous structures were investigated with 20 MHz ultrasound. This stu dy was performed to obtain data on normal nails in adults of different age groups, with a left-right comparison, and to investigate nail changes in se lected dermatologic diseases. Methods: Healthy controls (n=34) and patients with dermatologic complaints and nail disease (n=37) were included after informed consent. In the contro l group, 18 woman and 16 men with a mean age of 37.2 years (range 15 to 82 years) were investigated for age- and gender-related differences. Patients with one of the following disorders were investigated: systemic lupus eryth ematosus (SLE; n=11), systemic sclerosis (PSS; n=8), psoriasis (n=9), chron ic hand eczema (n=5), and others (n=4). Measurements of length and width of the nail plate and the lunulae were performed with a micrometer device. So nography was performed with a 20 MHz probe in B-scan mode. Results: The mean nail thickness of healthy controls varied between 0.481 m m (right thumb) and 0.397 mm (left fifth finger). The nail volume and the m atrix volume disclosed a positive, but mostly nonsignificant, correlation f or all controls. Age-specific differences were investigated for both gender s. In men and women, the matrix volume increased significantly with age. Th e nail and matrix volume was higher in men than in women, independent of ag e. The left-right comparison disclosed a trend to higher nail and matrix Vo lumes on the right hand. In patients with SLE there was an increase in nail thickness and in matrix volume. Patients with PSS showed a significant dec rease in nail thickness and matrix volume. In other diseases the measuremen ts disclosed no confident differences to healthy controls. Conclusion: The 20 MHz ultrasound offers a noninvasive method to calculate nail thickness, nail volume and matrix volume in healthy volunteers and in nail disease. Skin diseases show characteristic quantitative changes in the se parameters.