A dermatological diagnostic and treatment system comprising: - a light source device, - a light flow collecting device, - an absorption spectroscopic measurement device (5, 6), and - a calculator, characterized in that: - the light source device is adapted to generate a first low-intensity light beam towards an epidermal surface of a patient, the first light beam extending over a spectral range or being tunable in wavelength over a spectral range, - the light flow collecting device being arranged to collect a first light flow by reflection and/or scattering of the first light beam on said epidermal surface, - the absorption spectroscopic measurement device (5, 6) is adapted to record a first spectroscopic measurement of the first light flow as a function of the spectral range, and - the calculator being adapted to receive the first spectroscopic measurement in the spectral range and to determine a first wavelength associated with an absorption of a pigment of said epidermal surface and a second wavelength associated with an absorption of another tissue constituent of said epidermal surface, and in that - the light source device includes a laser source tunable in wavelength inside the spectral range, the laser source being tunable in duration and/or rate and the laser source being adapted to generate a second treatment laser beam of high intensity at said first wavelength towards said epidermal surface and in that the dermatological diagnostic and treatment system further includes a temperature sensor and a feedback device (80, 90, 95), the temperature sensor being arranged to record a temperature measurement signal of said epidermal surface as a function of the application of the second laser beam and the feedback device (80, 90, 95) being configured to modify the duration and/or rate of the laser pulses as a function of the temperature measurement signal. - a light source device, - a light flow collecting device, - an absorption spectroscopic measurement device (5, 6), and - a calculator, - the light source device is adapted to generate a first low-intensity light beam towards an epidermal surface of a patient, the first light beam extending over a spectral range or being tunable in wavelength over a spectral range, - the light flow collecting device being arranged to collect a first light flow by reflection and/or scattering of the first light beam on said epidermal surface, - the absorption spectroscopic measurement device (5, 6) is adapted to record a first spectroscopic measurement of the first light flow as a function of the spectral range, and - the calculator being adapted to receive the first spectroscopic measurement in the spectral range and to determine a first wavelength associated with an absorption of a pigment of said epidermal surface and a second wavelength associated with an absorption of another tissue constituent of said epidermal surface, and in that - the light source device includes a laser source tunable in wavelength inside the spectral range, the laser source being tunable in duration and/or rate and the laser source being adapted to generate a second treatment laser beam of high intensity at said first wavelength towards said epidermal surface and in that the dermatological diagnostic and treatment system further includes a temperature sensor and a feedback device (80, 90, 95), the temperature sensor being arranged to record a temperature measurement signal of said epidermal surface as a function of the application of the second laser beam and the feedback device (80, 90, 95) being configured to modify the duration and/or rate of the laser pulses as a function of the temperature measurement signal.