The present disclosure relates to systems, methods, and uses of systems treating a skin condition with phototherapy. A system comprises (a) a phototherapy device comprising a phototherapy light source； (b) a patient computing device comprising a processor and a memory, the patient computing device configured to: transmit a first signal to the phototherapy device enabling operation of the phototherapy device according to one or more conditional prescription parameters, activate the phototherapy light source, and transmit a second signal reporting operation of the phototherapy device； and (c) a server configured to communicate with the patient computing device and receive the second signal. Also disclosed are systems, methods and compositions for controlling phototherapy treatments of the skin comprising (a) incorporating sun exposure into a prescribed phototherapy treatment； (b) quantitative measurement of erythema using digital image processing； (c) computer aided guidance for administration of targeted phototherapy； (d) treatment recommendations from outcome based analytics of a population of connected phototherapy devices； (e) an emollient with UV fading dye to visibly identify treated areas in the administration of targeted phototherapy.La présente invention concerne des systèmes, des procédés et des utilisations de systèmes servant à traiter une affection cutanée par luminothérapie. Un système comprend (a) un dispositif de luminothérapie comprenant une source lumineuse de luminothérapie ； (b) un dispositif de calcul patient comprenant un processeur et une mémoire, le dispositif de calcul patient étant conçu pour : transmettre un premier signal au dispositif de luminothérapie permettant le fonctionnement du dispositif de luminothérapie conformément à un ou plusieurs paramètres de prescription conditionnelle, activer la source lumineuse de luminothérapie et transmettre un second signal signalant le fonctionnement du dispositif de luminothérapie ； et (c) un serveur
