Calcinosis cutis following calcium chloride electrode paste application for auditory-brainstem evoked potentials...

Circumscribed calcification in the dermis (calcinosis cutis) has been reported following electroencephalographic and electromyographic studies at sites of electrode placement following application of an electrode paste containing calcium chloride. Prolonged exposure and skin microabrasions seem to increase the risk of this rare complication of electrode placement, which has not been previously reported following auditory brainstem evoked potential recordings. We report the appearance of localized dermal calcifications at the sites of electrode placement (forehead and retroauricular areas) following auditory brainstem evoked potential recordings in two children, aged 3 and 2 years, respectively. In both cases the electrodes were applied after gentle scrubbing with an ethanol-impregnated gauze and interposition of a calcium chloride bentonite magma paste. The recording took about 1 hour. Erythematous macules and plaques ranging from 4 to 12 mm in diameter, studded with small stony excrescences, appeared at the areas of electrode application 1 and 5 days later, respectively. Histopathologic study of 4 mm punch biopsy specimens showed amorphous dermal deposits of calcium salts. There was superficial ulceration and transepidermal elimination of the calcium deposits, as well as a foreign body tissue reaction in the surrounding dermis. In both patients small stony pellets were extruded during the healing process, which took 11 and 9 weeks, respectively, and left no scars.