Pruritis

Question 1

Name some chemical mediators of itch

Answer 1

Histamine
PGE2
ACh
Serotonin

Question 2

What nerve fibres are involved in transmitting itch?

Answer 2

Unmyelinated C fibres

Question 3

What is the main CNS mediator of itch?

Answer 3

Opiates

Question 4

What are the main mast cell degranulating stimuli?

Answer 4

Allergen
IgE
Substance P

Question 5

Give some mediators released in mast cell degranulation

Answer 5

Tryptase
Heparin
Histamine
Cytokines

Question 6

What are the four main causes of itch?

Answer 6

Pruritoceptive
Neuropathic
Neurogenic
Psychogenic

Question 7

What is the cause of a pruritoreceptive itch?

Answer 7

Something in the skin that triggers the itch

Question 8

What is the cause of a neuropathic itch?

Answer 8

Damage to the central or peripheral nerves causing itch

Question 9

What is the cause of a neurogenic itch?

Answer 9

No damage to CNS but itch caused by external stimuli acting on CNS receptors

Question 10

What is the cause of a psychogenic itch?

Answer 10

Psychological causes

Question 11

Give some systemic diseases associated with itch

Answer 11

Haematological
Parneoplastic
Liver/bile duct disease
Kidney disease
Thyroid disease

Question 12

Give some anti-itch treatments

Answer 12

Sedative anti-histamines
Emollients
Antidepressants
Phototherapy
Opiate antagonists