Abnormal cutaneous neurosensitivity in atopic skin

Having found an inability of patients with atopic eczema to distinguish different levels of iontophoretically applied histamine concentrations, as shown by their diminished vascular reactions and itch responses, and reviewing this result in the light of our new findings of smaller flare reactions and weaker itch sensations following different concentrations of intradermally injected substance P, we have concluded that unmyelinated afferent skin nerve fibres in these patients seem to be affected by the pathophysiological mechanism of atopic eczema. We therefore suspect that a down-regulation of histamine receptors at nerve endings compensates for elevated histamine release from cutaneous mast cells in patients with atopic eczema.