The purpose of this study is to determine if Botox is effective in the treatment of an experimentally induced itch that mimics chronic itch in healthy volunteers.
Several studies have shown that botulinum toxin type A (BoNT/A) has an antipruritic effect due to the inhibition of acetylcholine and other pruritic factors, such as substance P and glutamate. For instance, subcutaneous BoNT/A improves itch accompanied to hand eczema, dermatitis, lichen simplex, and rhinitis. Furthermore, a double-blind, placebo-controlled study showed that BoNT/A reduced histamine itch intensity in healthy men. Since acetylcholine has been shown to mediate itch in atopic dermatitis, this study aims to test the itch relieving effect of BoNT/A on a non-histaminergic model for chronic itch. This non-histaminergic model using the plant cowhage induces itch by activating protease activated receptor 2 (PAR2) receptors, which play a role in the itch of atopic dermatitis, also making this model better suited to test the efficacy of BoNT/A to relive chronic itch.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
35
Itch by VAS Itch Intensity at Baseline (Visit 1)
The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage.
Time frame: Baseline (Visit 1)
Itch by VAS Itch Intensity at 1 Week (Visit 2)
The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage.
Time frame: 1 week from Baseline
Itch by VAS Itch Intensity at 1 Month (Visit 3)
The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage.
Time frame: 1 Month from Baseline
Itch by VAS Itch Intensity at 3 Months (Visit 4)
The primary endpoint is to test the antipruritic effect of Botox using an itch visual analog scale (VAS) intensity scale as an outcome measure. The itch VAS intensity scale ranges from a minimum of 0 (no itch - best) to a maximum of 10 (maximum itch - worst). Participants will rate itch intensity after itch is induced with cowhage.
Time frame: 3 Months from Baseline
Change in Heat Pain Relief by VAS Pain Intensity Reporting After 1 Week, 1 Month, and 3 Months After Treatment
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A secondary endpoint is to see if Botox has a relieving effect on heat pain using a pain visual analog scale (VAS) intensity scale as an outcome measure. The pain VAS intensity scale ranges from a minimum of 0 (no pain - best) to a maximum of 10 (maximum pain - worst). Participants will rate pain intensity after pain is induced with a heat thermode.
Time frame: Baseline, 1 week, 1 month, 3 months