Improved quantitative sensory testing to assess nociceptor sensitivity before and after topical application of capsaicin

Improved quantitative sensory testing to assess nociceptor sensitivity before and after topical application of capsaicin - CAPSENSE

Status

Active, not recruiting

Phases

Unknown

Study type

Observational

Source

DRKS

Registry ID

DRKS00040719

Enrollment

Registered

2026-06-26

Start date

2026-09-01

Completion date

Unknown

Last updated

2026-08-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

G62

Interventions

Group 1: Electrical C-fiber stimulation protocols using an Isolated Bipolar Constant Current Stimulator (DS5) with half-sine wave stimuli (0.5 s, 0.2–1 mA), short 4-Hz sine wave stimuli at increasing

treatment frequency depends on symptoms

typically repeated after 12 weeks

Eligibility

Sex/Gender

All

Age

18 Years to 95 Years

Inclusion criteria

Inclusion criteria: The study will include patients with chronic pain who are already being treated regularly and successfully with topical capsaicin. No vulnerable groups will be included. The affected pain areas should be located in the extremities or the trunk.

Exclusion criteria

Exclusion criteria: Patients with known skin conditions presenting with current skin manifestations or skin injuries in the measurement areas will be excluded. Patients with pain in the trigeminal region will also be excluded, as no control data from healthy subjects are available for the facial tests. Patients will be excluded if, due to a language barrier, the study briefing or the assessment of pain intensity cannot be conducted in German or English.

Design outcomes

Primary

Measure	Time frame
The primary endpoint is the normalized pain rating during the 60-second 4-Hz stimulation in the pain area versus the control skin area before capsaicin (increase rather than adaptation) and the change in this rating one week after treatment. Additionally, the difference between the sums of pain ratings for half-sine stimuli (polymodal nociceptors only) and for 4-Hz sine stimuli (polymodal + silent nociceptors) in the pain area compared to the control skin before and after capsaicin. Subjective pain perception is assessed and analyzed using the Numerical Rating Scale (NRS). This is measured at three time points (T1 = before capsaicin application, T2 = T1 + one week, T3 = T1 + three months).	—

Measure

Time frame

The primary endpoint is the normalized pain rating during the 60-second 4-Hz stimulation in the pain area versus the control skin area before capsaicin (increase rather than adaptation) and the change in this rating one week after treatment. Additionally, the difference between the sums of pain ratings for half-sine stimuli (polymodal nociceptors only) and for 4-Hz sine stimuli (polymodal + silent nociceptors) in the pain area compared to the control skin before and after capsaicin. Subjective pain perception is assessed and analyzed using the Numerical Rating Scale (NRS). This is measured at three time points (T1 = before capsaicin application, T2 = T1 + one week, T3 = T1 + three months).

—

Secondary

Measure	Time frame
The secondary endpoint is the correlation between the reduction in spontaneous pain and the reduction in measured hypersensitivity of C-nociceptors.	—

Countries

Germany

Contacts

Public ContactMarco Zugaj

Klinik für Anästhesiologie des Universitätsklinikums Heidelberg, Sektion Schmerzmedizin

Marco.zugaj@med.uni-heidelberg.de+49 6221 56 36852

Outcome results

None listed

Source: DRKS (via WHO ICTRP) · Data processed: Aug 10, 2026