Efficacy of a skin care cream with TRPV1 inhibitor 4‐t‐butylcyclohexanol in the topical therapy of perioral dermatitis

Lactic acid sting test and capsaicin test differentially induce facial erythematous reaction in subjects with sensitive skin

BACKGROUND

Sensitivity skin (SS) is a common skin disorders, which have a various of clinical manifestation. Facial erythema is common objective symptom of SS. However, the reasons for the occurrence of erythema in sensitive skin are not fully understood.

AIMS

In this study, we preliminarily explain the possible factors inducing erythema of sensitive skin by evaluating facial erythematous reaction to lactic acid sting test (LAST) and capsaicin test (CAT) in subjects with sensitive skin.

METHODS

A total of 197 subjects were divided into five groups, that is, normal controls (NC), LAST-positive (LAST+ ), both LAST and CAT positive (L+ C+ ), both LAST and CAT negative (L- C- ) and CAT-positive (CAT+ ). Erythema index (EI), a* value, and tissue viability imaging (TIVI) were measured before and after LAST and CAT, The ΔEI, Δa*, and ΔTIVI before and after LAST and CAT were calculated, and the correlation between the scores of CAT, EI values, a* values, and TIVI values were analyzed to clarify the causes of facial erythema.

RESULTS

Our results showed that EI values and a* values were significantly higher in the L+ C+ and CAT+ group than in NC group, TIVI values were higher in the L+ C+ group than in NC group. ΔEI and Δa* values after LAST did not differ significantly among five groups. However, ΔEI values in L+ C+ group were higher than that in L- C- group, while Δa* values were higher in CAT+ group than in NC. Moreover, ΔTIVI values in L+ C+ group and CAT+ group were also significantly higher than that in NC group after capsaicin stimulation. CAT scores correlated positively with EI, a* and TIVI values.

CONCLUSION

Our results suggest that sensitive skin subjects with positive CAT are more likely to experience erythema reactions, and vasodilation is more pronounced after capsaicin stimulation. Reducing vascular and neural hyperreactivity could be therapeutic target in management of facial erythema in subjects with sensitive skin.

Microneedling with a Novel, n-3-PUFA-Rich Formulation Accelerates Inflammation Resolution to Improve Skin Recovery Outcomes in Adults with Healthy Skin

INTRODUCTION

Microneedling is a cosmetic procedure that leverages the skin's natural ability to heal in order to promote collagen formation and skin rejuvenation. To provide improved results, the technique can be combined with topical formulations. A new formulation of multiple actives, including omega-3 (n-3) polyunsaturated fatty acids (PUFAs), was designed to accelerate the resolution of inflammation and wound healing following micro-injury treatments, while enhancing the visible appearance of procedure results, including erythema, luminosity and skin texture.

METHODS

In this randomised, controlled, split-face study, we examined 32 healthy female participants aged 30-70 years for 4 weeks following microneedling treatment with a novel multiple-active-ingredient formulation or conventional microneedling protocol with a hyaluronic acid control serum. Changes in skin condition were assessed by blinded clinical photography and expert evaluation. Measurements were collected at baseline, 1 h, 1 day, 7 days and 28 days post treatment.

RESULTS

Significantly greater improvements in expert-assessed erythema, luminosity and skin texture were reported following application of the novel multiple-active-ingredient formulation than the hyaluronic acid control serum. This was confirmed by representative VISIA®-CR imaging.

CONCLUSION

These data provide new evidence for the role of a novel multiple-active-ingredient formulation for improving skin outcomes up to 28 days following microneedling in adults with healthy skin when compared with a hyaluronic acid serum. The n-3 PUFA content of this formulation may drive accelerated inflammation resolution and wound healing alongside the complementary action of the other active ingredients, leading to the observed improvements in erythema, luminosity and skin texture.

Transient Receptor Potential Channel Vanilloid 1 Contributes to Facial Mechanical Hypersensitivity in a Mouse Model of Atopic Asthma

Sensitive skin, a common pathophysiological feature of allergic diseases, is defined as an unpleasant sensation in response to stimuli that normally should not provoke such sensations. However, the relationship between allergic inflammation and hypersensitive skin in the trigeminal system remains to be elucidated. To explore whether bronchial allergic inflammation affects facial skin and primary sensory neurons, we used an ovalbumin (OVA)-induced asthma mouse model. Significant mechanical hypersensitivity was observed in the facial skin of mice with pulmonary inflammation induced by OVA sensitization compared to mice treated with adjuvant or vehicle as controls. The skin of OVA-treated mice showed an increased number of nerve fibers, especially rich intraepithelial nerves, compared to controls. Transient receptor potential channel vanilloid 1 (TRPV1)-immunoreactive nerves were enriched in the skin of OVA-treated mice. Moreover, epithelial TRPV1 expression was higher in OVA-treated mice than in controls. Trigeminal ganglia of OVA-treated mice displayed larger numbers of activated microglia/macrophages and satellite glia. In addition, more TRPV1 immunoreactive neurons were found in the trigeminal ganglia of OVA-treated mice than in controls. Mechanical hypersensitivity was suppressed in OVA-treated Trpv1-deficient mice, while topical skin application of a TRPV1 antagonist before behavioral testing reduced the reaction induced by mechanical stimulation. Our findings reveal that mice with allergic inflammation of the bronchi had mechanical hypersensitivity in the facial skin that may have resulted from TRPV1-mediated neuronal plasticity and glial activation in the trigeminal ganglion.

Clinical studies in Chinese subjects investigating the tolerance and soothing efficacy of a cream and balm containing 4-t-butylcyclohexanol on the sensitivity of facial skin

INTRODUCTION

Asian subjects are particularly prone to skin sensitivity. We developed a facial cream and balm containing 4-t-butylcyclohexanol to provide skin comfort and a soothing effect for sensitive skin.

OBJECTIVES

Assess the dermatological and ophthalmological tolerance and efficacy in improving skin sensitivity of face cream and balm under normal conditions of use by a population known to be particularly prone to this problem.

METHODS

In a monocentric non-randomized open trial, the cream or balm was applied twice daily to the face, neck, and eye contour of 33 stinger subjects with hypersensitive skin (22-63 years old). Assessments included dermatological and ophthalmological physical and functional signs on Day 1 (D1), D8, and D22, and cosmetic acceptability, cutaneous sensitivity according to a stinging test and the sensitive scale, and the soothing efficacy according to a questionnaire on D22.

RESULTS

The cream and balm were very well tolerated. Immediately after application, subjects reported a reduction in the skin's hypersensitivity (93.9% of subjects for the cream and 81.8% for the balm), skin redness (90.9% of subjects for the cream and 87.9% for the balm), sensations of tightness (93.9% for the cream and 97.0% for the balm), and discomfort sensations (93.9% for the cream and 87.9% for the balm). After 21 days, the application of the cream and balm decreased the stinging scores by 65% and 41%, respectively, with 94% and 77% of subjects showing an improvement, respectively. The sensitivity scale questionnaire indicated that the cream and balm significantly and profoundly decreased all negative signs, for example, irritability, stinging, general discomfort, redness, and dryness on D22 compared to D1. On D22, all 15 parameters recorded were improved by 89%-100% by the cream and by 74%-100% by the balm. The majority (90.9% and 96.8% of subjects using the cream and balm, respectively) of the subjects noticed positive changes in their skin condition after using the product for 21 days.

CONCLUSIONS

The cream and balm were very well-tolerated. This study demonstrated that both products controlled and markedly reduced skin hypersensitivity in Asian subjects, with an immediate and lasting skin soothing and repairing effect over 21 days.

Inhibition of Nematocyst Discharge from Pelagia noctiluca (Cnidaria: Scyphozoa)—Prevention Measures against Jellyfish Stings

Pelagia noctiluca stings are common in Mediterranean coastal areas and, although the venom is non-lethal, they are painful. Due to its high toxicity and abundance, P. noctiluca is considered a target species for the focus of research on active ingredients to reduce the symptoms of its sting. To determine the effect of 31 substances and formulations on nematocyst discharge, we performed three tests: (1) screening of per se discharge activator solutions, (2) inhibitory test with nematocyst chemical stimulation (5% acetic acid) and (3) inhibitory test quantifying the hemolytic area. Ammonia, barium chloride, bleach, scented ammonia, carbonated cola, lemon juice, sodium chloride and papain triggered nematocyst discharge. All of them were ruled out as potential inhibitors. Butylene glycol showed a reduction in nematocyst discharge, while the formulations of 10% lidocaine in ethanol, 1.5% hydroxyacetophenone in distilled water + butylene glycol, and 3% Symsitive® in butylene glycol inhibited nematocyst discharge. These last results were subsequently correlated with a significant decrease in hemolytic area in the venom assays versus seawater, a neutral solution. The presented data represent a first step in research to develop preventive products for jellyfish stings while at the same time attempting to clarify some uncertainties about the role of various topical solutions in P. noctiluca first-aid protocols.

TRPV1 in Pain and Itch

Transient receptor potential vanilloid type 1 (TRPV1) is a nonselective cation channel that is intensively expressed in the peripheral nerve system and involved in a variety of physiological and pathophysiological processes in mammals. Its activity is of great significance in transmitting pain or itch signals from peripheral sensory neurons to the central nervous system. The alteration or hypersensitivity of TRPV1 channel is well evidenced under various pathological conditions. Moreover, accumulative studies have revealed that TRPV1-expressing (TRPV1⁺) sensory neurons mediate the neuroimmune crosstalk by releasing neuropeptides to innervated tissues as well as immune cells. In the central projection, TRPV1⁺ terminals synapse with the secondary neurons for the transmission of pain and itch signalling. The intense involvement of TRPV1 and TRPV1⁺ neurons in pain and itch makes it a potential pharmaceutical target. Over decades, the basis of TRPV1 channel structure, the nature of its activity, and its modulation in pathological processes have been broadly studied and well documented. Herein, we highlight the role of TRPV1 and its associated neurons in sensing pain and itch. The fundamental understandings of TRPV1-involved nociception, pruriception, neurogenic inflammation, and cell-specific modulation will help bring out more effective strategies of TRPV1 modulation in treating pain- and itch-related diseases.

Perioral dermatitis: diagnosis, proposed etiologies and management

Perioral dermatitis is a common cutaneous condition characterized by acneiform facial eruptions often with an eczematous appearance. A granulomatous subtype exists in addition to the classic variant. Whilst topical corticosteroids have been largely implicated in this condition, its etiology is not completely understood. Using the keywords "corticosteroids," "dermatology," "fusobacteria," "perioral dermatitis", and "periorificial dermatitis" we searched the databases PubMed, MEDLINE and EMBASE to find the relevant literature. Only articles in English were chosen. The level of evidence was evaluated and selected according to the highest level working our way downwards using the Oxford Centre of Evidence-Based Medicine 2011 guidance. This systematic review found the strongest evidence to support topical corticosteroid misuse as the principal causative factor in the pathogenesis of perioral dermatitis. In terms of treatment, further research is required to robustly investigate promising treatment options including tetracyclines, topical metronidazole, topical azelaic acid, adapalene gel and oral isotretinoin.