Two patients with nevus anemicus were studied by pharmacologic, histologic, and histochemical techniques.
The axon reflex from the nevi was found to be intact.
Microscopically, the vasculature of the nevus was normal with hematoxylin-and-eosin and with alkaline-phosphatase staining.
Vasodilation of the vessels of nevus anemicus was not produced by stroking or by intralesional injections of acetycholine, pilocarpine, histamine, or serotonin.
The defect of nevus anemicus may, therefore, be at the motor end plate or at the smooth muscle effector cell of the blood vessels, perhaps associated with an increased stimulation of the vasoconstrictor fibers or of inhibition of the vasodilator fibers of the arterioles.
Fleisher TL, Zeligman I. Nevus Anemicus. Arch Dermatol. 1969;100(6):750-755. doi:10.1001/archderm.1969.01610300100019