Chronic pruritus is a major symptom of atopic dermatitis (AD). Its etiopathogenesis is complex, and an understanding of the driving factors of its pathogenesis allows for the development of new molecule-targeted therapies. Dupilumab, targeting and blocking interleukin-4 (IL-4) and interleukin-13 (IL-13) molecules, has shown great efficacy in treating AD symptoms such chronic itching. We performed a retrospective observational study to evaluate possible chronic-itch-related characteristics and parameters in 356 AD patients who received dupilumab. The objective of the study was to evaluate the factors associated with the level of pruritus reported by patients at each of the 1575 detections in the form of the peak pruritus numerical rating scale (NRSpp) and sleep disturbance numerical rating scale (NRSsd). We focused on: the eczema area and severity index (EASI), dermatology life quality index (DLQI), patient-oriented eczema measure (POEMS), eosinophilia, L-lactate dehydrogenase (LDH), immunoglobulin E (IgE) and the time from the start of dupilumab therapy. NRSpp fell from 8.6 (sd 1.7) at baseline to 1.7 (sd 2.3) at 36 months and NRSsd from 7 (sd 3) to 0. Regarding the parameters that correlate with NRSpp, all the parameters analysed were significantly correlated except for eosinophils (p = 0.136). In the multivariate analysis, both considering and not considering treatment duration, the parameters were correlated (p < 0.001); EASI, DLQI, POEM, and LDH significantly correlated with NRSpp (p < 0.001 for each, except for LDH p = 0.003); while IgE tot lost significance (p = 0.337). Similar results were obtained for the parameters correlating with NRSsd. Our results confirm the efficacy of dupilumab on pruritus. The use of questionnaires such as DLQI and POEM is advisable in clinical practice and is adequate for assessing the impact of itching on AD. The low correlation of IgE and eosinophils, the ambiguity of LDH levels with the level of pruritus, and a poor clinical validity and unclear correlation with disease severity suggest a progressive abandonment of monitoring of these values.
Keywords: atopic dermatitis; dupilumab; itching; pruritus; quality of life.