The use of topical over-the-counter (OTC) products with a warming or cooling effect is widespread in the fields of sport, physiotherapy and in private households. Advertisements for such products promise pain relief when suffering from musculoskeletal disorders such as muscle tension, rheumatism or acute injuries, e.g. sprains. In literature, there are only little information about the efficacy and the physiological mechanisms of topical warming or cooling products. Therefore, the aim of this study is to investigate the local skin characteristics during and after an application of a topical product with a warming or cooling effect.
The use of topical products for local pain relief in chronic or acute musculoskeletal disorders is widely used. Despite the widespread use of these products, there is missing information on the physiological mechanisms and efficacy of topical warming and cooling ointments. Most of the existing literature is about the efficacy of topical non-steroidal anti-inflammatory drug (NSAID)-products on chronic pain in osteoarthritis. Furthermore, one study tested the cooling effect of gels with different menthol concentrations. They found that, regardless of the concentration, the skin temperature was reduced up to one hour post application in the area of application. The aim of our study is to evaluate the change of skin characteristics after a single application of a warming or cooling topical product on healthy subjects. Outcome parameters include skin perfusion, temperature, skin redness and subjective thermal sensation. We only selected products in form of alcohol based ointments, menthol or wintergreen oil. Sprays and patches were excluded. The application area is the unilateral lumbar back region, whereas the contralateral side serves as control area. After an acclimatization period, baseline measurements are performed, followed by standardized application of the topical product. The local skin responses are measured in 10 mins time increments up to one hour.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
21
Axanova hot gel is a topical product with a warming effect. It contains menthol, pine needle oil, wintergreen oil, rosemary oil, eucalyptus oil, incense oil.
Axanova activ gel is a topical product with a revulsive effect. It contains menthol, pine needle oil, orange oil, lemon oil, wintergreen oil, glycosaminoglycans.
Perskindol Dolo Gel is a topical product with a warming effect. It contains wintergreen oil, pine needle oil, aromatics, excipients.
Perskindol Classic Gel is a topical product with a revulsive effect. It contains menthol, wintergreen oil, pine needle oil, lemon oil, orange peel oil, lemon bergamot oil, rosemary oil, lavender oil, excipients.
Perskindol Cool Kühl-Gel is a topical product with a cooling effect. It contains levomenthol, color E131, aromatics, excipients.
Dolor-X Hot Gel is a topical product with a warming effect. It contains isopropyl alcohol, water, menthol, hyprolose, camphor, trometamol, paprika, wintergreen oil, excipients.
Dolor-X Classic Gel is a revulsive product. It contains water, isopropyl alcohol, menthol, spruce, hyprolose, trometamol, wintergreen oil, excipients.
Dolor-X Cool Gel is a cooling product. It contains water, isopropyl alcohol, menthol, trometamol, color E131, excipients.
SUPSI
Landquart, Kanton Graubünden, Switzerland
Local Skin Perfusion
Local skin perfusion was measured with laser speckle contrast imaging (LSCI). The LSCI system uses arbitrary units to express the mean flux in the specified regions of interest which is related to the concentration of circulating erythrocytes in the tissue sample volume, scaled from blue (low perfusion) to red (high perfusion).
Time frame: during 45min post application
Skin Surface Temperature
skin surface temperature will be measured with thermochrons, infrared thermometer and thermal imaging camera
Time frame: At baseline and during 45 minutes post application
Local Muscle Tissue Oxygenation
local muscle tissue oxygenation will be measured with near infrared spectroscopy
Time frame: At baseline and during 45 min post application
Subjective Temperature Sensation
Thermal sensation ("How does this feel like?") was assessed in each skin area according to the ISO 10551 standard using the following 9-point Likert scale: 4 = very hot, 3 = hot, 2 = warm, 1 = slightly warm, 0 = neutral,-1 = slightly cool,-2 = cool,-3 = cold,-4 = very cold.
Time frame: At baseline and during 45 minutes post application
Subjective Thermal Comfort
Thermal comfort was assessed ("Do you find this. . .?") in each skin area according to the ISO 10551 standard using using a 5-point Likert scale with 0 = comfortable, 1 = slightly uncomfortable, 2 = uncomfortable, 3 = very uncomfortable, 4 = extremely uncomfortable.
Time frame: At baseline and during 45 minutes post application
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