Relationship between transient receptor potential vanilloid‐1 expression and the intensity of sensitive skin symptoms

Summary Background Sensitive skin ( SS ) is a hyper‐reactive condition of the skin secondary to external factors, without objective signs of lesion. Its pathogenesis is still under investigation. Transient receptor potential vanilloid‐1 ( TRPV 1) is a cation channel that responds to low pH and is related to nociception, neurogenic inflammation, and pruritus. Aims To determine the expression of TRPV 1 in subjects with SS and correlate it with the degree of symptoms and skin pigmentation. Patients/Methods We included 31 subjects self‐diagnosed as having SS . Colorimetric values were obtained for assessment of skin phototype, and the lactic acid stinging test ( LAST ) was performed. Two skin biopsies from the nasolabial fold of each volunteer were obtained. Qualitative analysis of TRPV 1 was carried out with immunohistochemistry. Quantitative analysis of TRPV 1 was carried out with qRT ‐ PCR . Results LAST was positive in 74% of the subjects, 56% of those having tan and brown skin. Immunohistochemistry staining for TRPV 1 was greater in positive subjects ( P = 0.03), but showed no correlation with the intensity of symptoms. Positive subjects also had higher TRPV 1 mRNA expression compared to negative subjects ( P < 0.001). This expression showed a positive correlation with the intensity of referred symptoms ( R = 0.75, P < 0.001) and skin pigmentation ( R = 0.63, P < 0.001). Conclusions TRPV 1 expression is upregulated in subjects with sensitive skin, and it correlates with the intensity of the symptoms. Our findings suggest a role for this receptor in the pathogenesis of sensitive skin syndrome.