The handheld dermatoscope as a nail-fold capillaroscopic instrument.

BACKGROUND The presence of nail-fold capillary abnormalities may be useful in diagnosing several connective tissue disorders, including scleroderma, dermatomyositis, and mixed connective tissue disease, and in differentiating primary Raynaud phenomenon from Raynaud phenomenon due to scleroderma and mixed connective tissue disease. Capillaroscopy, however, usually requires special equipment and may be time consuming. Purpose To investigate the potential use of the unmodified common handheld dermatoscope as a capillaroscopic instrument. Subjects The study included 106 patients who were consecutively referred and a control group of 170 healthy subjects or patients with unrelated skin disorders. METHODS A nail-fold capillaroscopic examination using a standard handheld dermatoscope was performed on all fingers of each subject. A scleroderma-dermatomyositis pattern was defined as the presence of 2 or more of the following findings in at least 2 nail folds: enlargement of capillary loops, loss of capillaries, disorganization of the normal distribution of capillaries, "budding" ("bushy") capillaries, twisted enlarged capillaries, and capillary hemorrhages (extravasates). RESULTS A scleroderma-dermatomyositis pattern was found in 19 (70.4%) of 27, 7 (63.6%) of 11, and 4 (50%) of 8 patients with scleroderma, dermatomyositis, and mixed connective tissue disease, respectively. These frequencies were statistically significantly higher than a null percentage of scleroderma-dermatomyositis pattern in the control group (P<.001) and a scleroderma-dermatomyositis pattern in only 1 (4.5%) of 22 patients with systemic lupus erythematosus as well as in 2 (5.3%) of 38 patients with Raynaud phenomenon but without evidence of a connective tissue disorder (P<.01). CONCLUSIONS The capillaroscopic results obtained with the dermatoscope are comparable to those described with other instruments. Therefore, the unmodified hand-held dermatoscope may be used as a capillaroscopic instrument to detect a scleroderma-dermatomyositis pattern and to help the dermatologist in the clinical diagnosis of connective tissue disorders.