Nail surfaces of toe-nail fragments were analysed by optical profilometry in patients treated with two different dosages of itraconazole: 200 mg continuous dosing for 12 weeks, or a pulse-dose regimen of 1 week per month of 400 mg itraconazole daily for 3-4 months. The use of the latter regimen seemed clinically to increase nail growth, which was accompanied in several patients by the occurrence of nail surface irregularities. This aspect was studied by computerized optical profilometry. Nail beading was characterized by a higher number of peaks and a larger mean roughness value (Ra). Such findings are reminiscent of other nail alterations resulting from a faster matrix turnover. A substantially greater number of peaks and larger Ra were found in the patients receiving the pulse treatment than in those receiving the continuous-dose regimen. Pulse therapy with itraconazole therefore appears to modify the structure of the nail plate, probably as a result of, or in association with, an increased rate of growth.