An intradermal injection adapter includes a body having a longitudinal axis and a central portion located distally relative to the body along the longitudinal axis. The central portion has a cannula channel therethrough extending generally parallel to the longitudinal axis. A cannula within the cannula channel has a sharpened tip for injection into a patient and a sharpened opposite proximal end for injection into a pen injector. A distal protrusion has a first skin contacting surface extending generally parallel to the longitudinal axis. The first skin contacting surface is spaced from the cannula such that a distal portion of the cannula extends generally parallel to the first skin contacting surface.