Itch

Itch
A man scratching his back
Specialty	Dermatology
Symptoms	Compulsion to scratch an irritated area of skin
Causes	Certain infections, allergies, blood derangements and environmental factors
Risk factors	Dry skin
Diagnostic method	Often based on the causes of itching
Differential diagnosis	Pain
Treatment	Antipruritics, phototherapy

Itch (also known as pruritus) is a sensation that causes a strong desire or reflex to scratch.^[1] Itches have resisted many attempts to be classified as any one type of sensory experience. Itches have many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response patterns are different. Pain creates a withdrawal reflex, whereas itches leads to a scratch reflex.^[2]

Unmyelinated nerve fibers for itches and pain both originate in the skin. Information for them is conveyed centrally in two distinct systems that both use the same nerve bundle and spinothalamic tract.^[3]