The drug line: the clinical expression of the pigmentary Voigt-Futcher line in turn derived from the embryonic ventral axial line.
BACKGROUND
Observation of patients with morbilliform eruptions reveals a distinctive demarcation line on the upper arms.


OBJECTIVE
We studied the origin of this sharp "drug line."


METHODS
We performed a literature search of all known variables.


RESULTS
The drug line represents clinical expression of the pigmentary Voigt-Futcher line.


CONCLUSIONS
The drug line reveals the otherwise inapparent embryologic ventral axial line, which marks the precise border between the sensory innervation of the lateral and medial upper arm. The significance of the cutaneous sensory nerves is thus apparent. The drug line is further evidence of the segmental nature of human skin, as evidenced in evolutionary and embryologic studies.
D001132:Arm / Q000196:embryology / Q000294:innervation / Q000473:pathology*; D003875:Drug Eruptions / Q000473:pathology*; D005076:Exanthema / Q000473:pathology*; D006801:Humans; D009475:Neurons, Afferent / Q000648:ultrastructure; D013126:Spinal Nerve Roots / Q000033:anatomy & histology / Q000196:embryology