Dictionary.net

Any skin disease due to an affection of the stratum mucosum or spinosum.

An affection of the prickle-cell layer of the skin. A. nigricans, a hyperplasia of the prickle-cells and papillary layer of the skin, so that the skin becomes darker, and flat warty growths form upon it and upon the mucous surfaces.

Any disease of the prickle layer of the skin.

Any disease of the prickle cells of the skin.