Performance and Tolerance of Cyto-selective Difluoroethane-based Cryotherapy in th Treatment of Brown Spots (Solar and Senile Lentigines, Post-Inflammatory Hyperpigmentation) on the Face and Hands of Asian Ethnicity Skins

CS5\_4 study aim to evaluate the performance and the tolerance of 3 prototypes of cyto-selective cryotherapy treatments applied on the brown spots on the face and hands of asian ethnicity skins (chinese). A brown spot is defined as solar or senile lentigo (SSL) and post-inflammatory hyperpigmentation (PIH). Each treatment corresponds to a combination of a specific sequence of cryogenic spray and of a frequency of application. Each spot will be treated by a defined prototype (always the same device on the same spot all along the study). The study will evaluate the following prototype : * Prototypes 1 * Prototypes 2 * Prototypes 3

Rational : Solar/senile lentigo (SSL) is a harmless patch of darkened skin. It results from exposure to ultraviolet (UV) radiation, which causes local proliferation of melanocytes and accumulation of melanin within the skin cells (keratinocytes). Solar/senile lentigos or lentigines are very common, especially in people over the age of 40 years. Solar/senile lentigines are found as groups of similar lesions on sun-exposed sites, particularly the face or the back of hands. Post-inflammatory hyperpigmentation (PIH) is an area of darker skin that remains after a pimple or wound heals. The discoloration is due to the production of excess melanin (pigment) as part of the skin's natural response to inflammation. CRYONOVE is a medical device intended to induce a cyto-selective cryogenic action on melanocytes to remove brown spots resulting from solar or senile lentigines, post-inflammatory hyperpigmentation and melasma on the face and body. Cryotherapy is more and more used to improve skin appearance and currently used to treat lentigo spot. Devices using difluoroethane, manufactured by CRYONOVE PHARMA, are already available on the local and international markets, e.g. CRYOBEAUTY MAINS and CRYOBEAUTY CORPS. However, the cryogenic gas (conventional cryotherapy - liquid nitrogen) creates a dermabrasion of the skin surface and person receiving this kind of treatment presents an impaired skin during a few days following the treatment as temporary damage of stratum corneum, erythema, scars, burns. Following the side effects occurring after conventional cryotherapy application, it seems interesting for the sponsor to select other sequences of a cryogenic spray (3 prototypes of devices for face and hands used according to different frequencies of application, i.e., 5 conditions evaluated) which could be used for lentigo and post inflammatory hyperpigmentation treatment in Asian Ethnicity Skin with a same benefit for the consumers without any safety outcomes. Design: The study performed is a proof of concept, exploratory, interventional, monocentric, randomized and single blinded Intervention : 3 prototypes of devices are evaluated in 5 different conditions. Each treatment corresponds to a combination of a specific sequence of cryogenic spray and of a frequency of application. For the conditions 1, 3, 4 and 5, each spot will be treated 6 times during the study : * Every day from D0 and thus until D5 (condition 1); * Every two weeks: at D0, D14, D28, D42, D56 and at D70 (condition 3): * Every two weeks: at D0, D14, D28, D42, D56 and at D70 (condition 4); * Every two weeks: at D0, D14, D28, D42, D56 and at D70 (condition 5). For the condition 2, each spot will be treated 12 times during the study: • Every week: at D0, D7, D14, D21, D28, D35, D42, D49, D56, D63, D70 and at D77 (condition 2); 120 participant will be included in the study. Overall, this study leads to treat 240 face spots (PIH, SSL) and 40 hands spots (SSL) with 3 prototypes having different temperature and kinetic. Prior to any study device application, the dermatologist will assess the adverse events and will decide if the period between two consecutive applications should be extended or not.The dermatologist will verify that the skin has not been treated by cosmetic products (no presence of cream that could interfere with the treatment) and is dry. An operator previously trained by the dermatologist will apply the study device to the patient's face or hands. Subjects will be lying down, and the device will be administered upside down. During applications on the face, subjects will wear diving goggles protecting the eyes from cryogenic gas. For the application on the hands, the hands will be placed flat on the table and the prototypes will be applied upside down.The treatment will be stoped after the disappearance of the spot. The patient follow-up visits are from Day 0 to 6 months.