Effectiveness of Narrowband Ultraviolet Light in Chronic Kidney Disease-Associated Pruritus.

INTRODUCTION

Chronic kidney disease-associated pruritus (CKDaP) is a prevalent and challenging symptom in individuals suffering from advanced chronic kidney disease (CKD). Its underlying mechanism remains inadequately understood, leading to a limited array of unsatisfactory therapeutic interventions. Despite various attempts, identifying the most effective treatment remains inconclusive. Nevertheless, there is a growing interest in employing ultraviolet phototherapy, particularly for non-responsive patients, although its efficacy is not definitively established. To investigate the potential benefits of narrowband ultraviolet B (NB-UVB) phototherapy on individuals experiencing CKDaP, we report our experience with NB-UVB light in management of CKDaP in dialysis patients.

MATERIALS AND METHODS

The study group consisted of patients with end-stage chronic kidney disease who underwent hemodialysis. These patients received dermatological consultations and follow-ups for itching. They were all unresponsive to the conventional treatment (emollients and antihistamines). Screening laboratory examinations, including complete blood count, liver function test, thyroid function, electrolytes, and others, were also arranged to exclude systemic etiologies. The main potential pruritogens were dosed: calcium, phosphate, and parathyroid hormone. Itch intensity was evaluated with a numerical rating scale (0-10), based on the worst level of itching in the past two weeks. They had sessions of NB-UVB light (311 nm, TL01) twice per week. After UVB exposure, patients were advised to use topical emollients. A questionnaire was employed to document the extent, intensity, frequency, and sleep disruption experienced to evaluate the efficiency of the treatment, using a scale from 0 to 10.  Results: In a group of 38 patients, the average age of the patients was 56 years (16-80); 63.2% were female and 36.8% were male. Median duration of pruritus was 4.7 years, and that of dialysis was 8.4 years. Pruritus was intermittent and diffuse in most cases, localized to the arteriovenous fistula site in two cases, and exacerbated by heat in all cases. Itch intensity was evaluated with a numerical rating scale (0-10) based on the worst level of itching in the past two weeks and showed a moderate average score (5/10). Xerosis was found in 63%, and scratch lesions such as excoriation in 34%. NB-UVB phototherapy was used twice per week on nonconsecutive days, with protection of the genital area and also the eyes using UVB-blocking goggles. The initial dose was 0.4 J/cm and further doses were introduced according to the erythema response until a maximum of 2 J/cm. No sunburn, hyperpigmentation, or blistering was noted. Emollients were maintained in patients with xerosis. Average number of sessions was 13 (6-24) and reduction of itch intensity was observed starting from the sixth session. Total improvement was obtained at the end of treatment duration except for three patients who required additional sessions. One patient had recurrence one year later.  Conclusion: In conclusion, phototherapy represents a significant advancement in the treatment options for CKD-associated pruritus. Its positive impact on reducing itching and improving the quality of life for many patients is undeniable. However, to fully unlock its potential, ongoing research is needed to optimize dosing, understand relapse mechanisms, and identify the patients who will benefit most from this therapy.