Embodiments of the present invention generally relate to methods, devices, and systems for reducing a pigmentation of a skin of a patient. In some embodiments, freezing of the skin may be desirable to effect the hypopigmentation of the skin of the patient. Generally, embodiments may limit supercooling (or promote freezing) of the skin of the patient during a cooling treatment. In some embodiments, coupling fluids are provided to reduce a thermal contact resistance between a cooling treatment probe and the skin of the patient to improve cooling treatment. Optionally, a fluid carrier may be provided to help retain the coupling fluid at the treatment site. In some embodiments, the coupling fluid may include ice nucleating agents to promote ice crystal formation in the coupling fluid during cooling treatment. The ice crystal formation in the coupling fluid may progress into the skin to limit supercooling of the skin during treatment.
