To assess the benefit of the Avène hydrotherapy in subjects with pruritic plaque psoriasis in the:~Improvement of pruritus~Improvement of psoriasis severity~Improvement of quality of life~Change of pruritus and psoriasis biological markers~Intake/application of treatments and skin care products for psoriasis and pruritus management, evaluated during a follow-up period~To assess the time to pruritus relapse evaluated in subjects with pruritic plaque psoriasis, during the period following the Avène hydrotherapy (for the hydrotherapy group only)~To assess the global efficacy of the Avène hydrotherapy in pruritic plaque psoriasis, according to subjects' and investigators' opinion (for the hydrotherapy group only)~To assess the global cutaneous tolerance of the Avène hydrotherapy in subjects with pruritic plaque psoriasis (for the hydrotherapy group only)
To assess the benefit of the Avène hydrotherapy in subjects with pruritic plaque psoriasis