Measurement of skin swelling in the tuberculin test by ultrasonography.

A new method is described for non-invasive measurement of the thickness of the skin at the site of a skin test from the echo pattern of a pulsed ultrasonic (15 MHz) A-mode scanner. In tuberculin tests on normal volunteers, the skin thickness increased rapidly during days 1 and 2 and was usually greatest at day 4. The echogram measurements can be used to calculate the increase in skin volume and this is disproportionately greater than would be expected from measurements of the diameters of erythema and induration.