Table 1.

(Adapted from Vollert et al., 2017). Predicted Benefits of Different Analgesic Classes in 3 DFNS-defined Subgroups

Cluster Characteristics, Hypotheses About Underlying Pathophysiology, and Expected Treatment Efficacy
	Sensory Loss	Thermal Hyperalgesia	Mechanical Hyperalgesia
Sensory profile
Sensory Loss	Touch, thermal, pain	None	Mostly thermal
Hyperalgesia	None	Mostly cold & heat	Mostly pressure & pain
DMA	Little	Little	Much
PHS	Much	Little	Little
Pathophysiology
Sensory Loss	Small & large fibers	—	Mostly small fibers
Hyperalgesia	—	Peripheral sensitization	Central sensitization
Ongoing Pain	Ectopic activity	Spontaneous activity	Ectopic activity
Predicted Findings
IENFD	Loss	None	Mild loss
CCM	Loss	None	Mild loss
Peripheral MRI	Damage	None	Mild damage
LEP	Reduction	Normal or gain	Mild reduction
RIII	Reduction	Normal or gain	Gain
μENG	Denervation	Sensitization	Little denervation
Predicted Efficacy
NSAIDS	—	(+)	—
Botox		+
Topical capsaicin		+
NMDA antagonist			+
SNRI	++	+	+
Gabapentinoid	+	+	++
Sodium channel blocker	+	++	++
Opioid	++	+	+

CCM, confocal corneal microscopy; DMA, dynamic mechanical allodynia; IENFD, intraepidermal nerve fiber density; LEP, laser-evoked potentials; μENG, microneurography; PHS, paradoxical heat sensation; RIII, nociceptive flexion reflex; SNRI, serotonin-norepinephrine reuptake inhibitor.