Rational:~Solar lentigo 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 lentigos or lentigines are very common, especially in people over the age of 40 years. Solar lentigines are found on sun-exposed sites, particularly the face or the back of hands.~Cryotherapy is more and more used to improve skin appearance and currently used to treat lentigo spot. 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, the Sponsor has developed some devices using difluoroethane, manufactured by CRYONOVE PHARMA, already available on the local and international markets, e.g. CRYOBEAUTY MAINS and CRYOBEAUTY CORPS.~To continue it research and development activities, it seems interesting for the sponsor to select other sequences of a cryogenic spray which could be used for lentigo treatment with a same benefit for the consumers without any safety outcomes.~Design:~The study is a proof of performance designed to be interventional, monocentric, randomized and double blinded.~Intervention:~Three prototypes of devices are evaluated in 4 different conditions. A total of 168 brown spots are needed (84 brown spots on the face and 84 brown spots on the hands). Each treatment corresponds to a combination of a specific sequence of a cryogenic spray and of a frequency of application.~Prototypes (815-v1 001) to (815-v1 200) will be applied on brown spots located on the face and/or hands. Each spot will be treated six times by a defined prototype (always the same prototype on the same spot all along the study) according to specific frequencies (evry day, every week or every 2 weeks).The application order of the different prototypes will be defined by randomization.~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/and hand.~Subjects will be lying down, and the prototypes will be administered upside down for the applications on the face and sitting for the applications on the hands. For the application on the hands, the hands will be placed flat on the table and the prototypes will be applied upside down. During applications on the face, subjects will wear diving goggles protecting the eyes from cryogenic gas.~The patient follow-up visits are from Day 0 to 6 months.
CS5_1 study aim to evaluate the tolerance and to adjust the mode of administration of 4 different conditions of cryotherapy treatments applied on the brown spots of the face and hand with 3 prototypes.~Each treatment corresponds to a combination of a specific sequence of a cryogenic spray and of a frequency of application.~The study will evaluate 3 prototypes :~Prototype 1 : from (815-v1 001) to (815-v1 100)~Prototype 2 : from (815-v1 101) to (815-v1 150)~Prototype 3 : from (815-v1 151) to (815-v1 200)