Measurement of Itch Intensity

Measurement of itch intensity is essential to properly evaluate pruritic disease severity, to understand the patients' needs and burden, and especially to assess treatment efficacy, particularly in clinical trials. However, measurement of itch remains a challenge, as, per definition, it is a subjective sensation and assessment of this symptom represents significant difficulty. Intensity of itch must be considered in relation to its duration, localization, course of symptoms, presence and type of scratch lesions, response to antipruritic treatment, and quality of life impairment. Importantly, perception of itch may also be confounded by different cofactors including but not limited to patient general condition and other coexisting ailments. In the current chapter we characterize the major methods of itch assessments that are used in daily clinical life and as research tools. Different methods of itch assessment have been developed; however, so far none is without limitations and any data on itch intensity should always be interpreted with caution. Despite these limitations, it is strongly recommended to implement itch measurement tools in routine daily practice, as it would help in proper assessment of patient clinical status. In order to improve evaluation of itch in research studies, it is recommended to use at least two independent methods, as such an approach should increase the validity of achieved results.