A PILOT STUDY INVESTIGATING WHETHER QUANTITATIVE SENSORY TESTING ALTERS FOLLOWING TOPICAL HIGH CONCENTRATION CAPSAICIN TREATMENT IN PATIENTS WITH NEUROPATHIC PAIN
Theresa Wodehouse, Charlotte Guest, Vivek Mehta, Shankar Ramaswamy.
Background and Aims 
Neuropathic pain is a common disabling condition and is often difficult to treat due to its heterogeneity of its aetiologies. Capsaicin, a component of chilli peppers is a natural ligand of the transient receptor potential vanilloid 1 (TRPV1) channel. High concentration transdermal capsaicin (Qutenza, 8% patch) was introduced and licenced to treat a diverse group of neuropathic pain disorders. Quantitative sensory testing (QST) is a psychophysical test that investigates the patients’ functional state of the somatosensory system.  To evaluate whether QST detects a change in pain response in patients receiving topical high concentration capsaicin treatment.   
Methods
20 patients will be recruited to receive routine application of capsaicin 8% patch (Qutenza, Grünenthal  GmbH, Germany). The patients are asked to come into clinic to have QST and questionnaires measured at baseline, 3 weeks and finally at 3 months following patch application. 
Results 
Patients with neuropathic pain demonstrated loss of CPM at baseline. A “normal’ CPM was observed at 3 weeks and this was maintained.  PPT’s showed a significant improvement from baseline.  Patients also reported a similar magnitude of improvements in the completed questionnaires.  
Conclusions 
The central sensitisation response particularly ‘dynamic responses’ to Capsaicin has not been reported before. This is the first study demonstrating improvement in peripheral and central sensitization as measured by QST in patients with neuropathic pain following treatment.

A PILOT STUDY INVESTIGATING WHETHER QUANTITATIVE SENSORY TESTING ALTERS FOLLOWING TOPICAL HIGH CONCENTRATION CAPSAICIN TREATMENT IN PATIENTS WITH NEUROPATHIC PAIN