The impact of phototherapy on itch intensity and itch-related quality of life amongst different skin diseases, skin phototypes and genders - A prospective study with 102 patients

Background: Phototherapy is a mainstay to treat itchy conditions. However, only little is known about differences in the antipruritic effect of phototherapy amongst different skin conditions, phototypes and genders.Methods: In this prospective, single-center study, we analyzed the effect of phototherapy on itch intensity and itch-related quality of life amongst these subgroups after a treatment duration of 4 weeks, while on-demand treatment with topical corticosteroids, topical calcineurin inhibitors and/or antihistamines was allowed.Results: Of 102 patients (age 53.0 +/- 18.7, 56 females [54.9%]), 72 (78.3%) reported a significant reduction of itch intensity by Delta -2.76 on a 0-10 Numerical Rating Scale (NRS), p = <.001, 95% CI [2.2; 3.3] paralleled by a significant improvement of itch-related quality of life as measured by the German version of the ItchyQoL by Delta 7.3, p = <.001, 95% CI [4.4; 11.6]. The best improvement of itch intensity and itch-related QoL was reported by patients with pruritus on non-diseased skin (Delta NRS -3.5; Delta 9.7 Ger-ItchyQoL points), followed by patients with atopic dermatitis and psoriasis. We found no statistical differences in the response to phototherapy amongst Fitzpatrick phototypes I-VI. Women had higher itch intensities at baseline but itch-related quality of life impairment at baseline and phototherapy treatment response did not significantly differ between genders.Conclusion: Phototherapy appears to induce a meaningful itch reduction in various itchy skin conditions, all phototypes and both genders within 4 weeks that directly translates into improvement of itch-related quality of life.