Skin Barrier Function in Women Using UV Nail Lamps

The goal of this observational study is to compare objective parameters of skin barrier function between healthy adult women who regularly use UV lamps during nail treatments and women who do not use UV lamps. The main questions it aims to answer are: * Do women who regularly use UV lamps for nail treatments show differences in skin barrier function compared to women who do not use UV lamps? * Are transepidermal water loss, skin hydration, and erythema associated with regular exposure to UV lamps used for nail treatments? * Does the duration of UV lamp use influence skin barrier function parameters? Researchers will compare women who regularly use UV lamps during nail treatments with women who have natural nails and do not regularly expose their hands to UV lamps. Participants will: * Attend a single study visit. * Complete a short questionnaire regarding nail care habits and duration of UV lamp use. * Undergo non-invasive measurements of skin barrier function on the hands, including transepidermal water loss, skin hydration, and erythema assessments.

Inclusion Criteria: * Healthy adult women (≥18 years of age) * Willing and able to provide written informed consent * Willing to complete the study questionnaire Exclusion Criteria: * Active skin diseases (e.g., psoriasis, vitiligo, or other dermatological conditions) * Allergic contact dermatitis * Pregnancy or breastfeeding * Use of topical or systemic corticosteroids, immunosuppressive drugs, or antihistamines