Physiology: Pruritus

Question 1

Define neuropathic itch

Answer 1

Itch caused by damage to central or peripheral nerves

Question 2

Which nerve fibres transmit itch?

Answer 2

Unmyelinated C fibers

Question 3

Define neurogenic itch

Answer 3

No evident damage in CNS but itch caused by e.g. opiate effects on CNS receptors, primary biliary cirrhosis

Question 4

Define pruritoceptive itch

Answer 4

Something (usually inflammation or dryness) in skin triggers itch

Question 5

Define psychogenic itch

Answer 5

Psychological causes of itch with no CNS damage e.g. itch in delusions of infestation