Evaluating the Role of Vitamin D in Alleviating Chronic Pruritus: A Meta-Analysis

Chronic pruritus is a distressing condition that significantly impacts patients' quality of life. Recent research has increasingly focused on the potential role of vitamin D, given its immunomodulatory properties, in managing this condition. This meta-analysis seeks to systematically assess the effectiveness of vitamin D supplementation in alleviating chronic pruritus across diverse clinical contexts. We conducted an extensive search through multiple databases, covering literature up to July 2024, to identify relevant randomized controlled trials (RCTs) that evaluated the effect of vitamin D on chronic pruritus. Eligible studies were those that provided data on changes in pruritus severity, as measured by standardized tools, before and after vitamin D treatment. The data were synthesized using a random-effects model to address variability among the studies. This meta-analysis is registered with PROSPERO (registration number: CRD42024579353). The findings indicate that vitamin D supplementation is associated with a significant reduction in pruritus severity, the skin lesion area, and levels of inflammatory cytokines, including tumor necrosis factor (TNF), interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hs-CRP), compared to controls. These results suggest that vitamin D could be a promising therapeutic option for chronic pruritus, though further rigorous studies are required to validate these findings and to elucidate the mechanisms involved.

Skin barrier: new therapeutic targets for chronic kidney disease-associated pruritus - a narrative review

The current incidence of chronic kidney disease-associated pruritus (CKD-aP) in patients with end-stage renal disease (ESRD) is approximately 70%, especially in those receiving dialysis, which negatively affects their work and private lives. The CKD-aP pathogenesis remains unclear, but uremic toxin accumulation, histamine release, and opioid imbalance have been suggested to lead to CKD-aP. Current therapeutic approaches, such as opioid receptor modulators, antihistamines, and ultraviolet B irradiation, are associated with some limitations and adverse effects. The skin barrier is the first defense in preventing external injury to the body. Patients with chronic kidney disease often experience itch due to the damaged skin barrier and reduced secretion of sweat and secretion from sebaceous glands. Surprisingly, skin barrier-repairing agents repair the skin barrier and inhibit the release of inflammatory cytokines, maintain skin immunity, and ameliorate the micro-inflammatory status of afferent nerve fibers. Here, we summarize the epidemiology, pathogenesis, and treatment status of CKD-aP and explore the possibility of skin barrier repair in CKD-aP treatment.

Chronic kidney disease-associated pruritus in patients undergoing hemodialysis: Xerosis and topical therapy

Chronic kidney disease-associated pruritus (CKD-aP) is a common and distressing symptom for patients with CKD and a difficult challenge for nephrologists and dermatologists. Recent results showed the multifactorial nature of the pathophysiology, and therapeutic trials were only successful in certain subsets of patients. The clinical manifestations are varied, with xerosis being the most common dermatological manifestation and correlated with the intensity of CKD-aP. A better understanding of the pathophysiology of xerosis in CKD-aP and appropriate topical treatment could correct xerosis to reduce the intensity of CKD-aP and improve the patient's quality of life.

Itch: Epidemiology, clinical presentation, and diagnostic workup

Itch, or pruritus, is the uncomfortable sensation underlying the desire to scratch. Itch is a very common complaint in the general population that can result from dermatologic, systemic (eg, renal, hepatobiliary, endocrine), paraneoplastic, neuropathic, and psychogenic etiologies. Chronic itch is associated with significant sleep disturbances and profoundly reduces overall quality of life. Certain populations, including elderly and African Americans, are at increased risk of experiencing heightened burden of itch. Because of the variable clinical presentation and wide-ranging etiologies, itch presents a challenge for clinicians. The initial evaluation should include a complete blood count, with differential, hepatic, renal, and thyroid function testing along with diabetes screening. Further testing should be guided by history and physical examination findings. There should be a heightened concern for underlying malignancy in individuals older than 60 years of age who have a history of liver disease and diffuse itch less than 12 months of duration. For individuals with chronic pruritus of unknown origin, increased blood eosinophils may serve as a biomarker of T helper cell type 2 polarization and response to immunomodulator therapies. In this first part of a 2-part continuing medical education series, we describe the broader epidemiology and specific conditions associated with itch and the clinical presentation and diagnostic workup for patients with itch.

Western and complementary alternative medicine treatment of uremic pruritus: A literature review

Uremic pruritus (UP), also called chronic kidney disease-associated pruritus (CKD-aP), is a bothersome symptom that causes sleep disturbance, anxiety, depression, and reduced quality of life. Pruritus often occurs in patients with end-stage renal disease. There is still no definite treatment for UP due to its unclear pathogenesis. We searched electronic databases (PubMed and Google Scholar) and gathered the latest clinical trials and pilot studies of Western and complementary alternative medicine (CAM) therapies for UP in English. These UP studies were separated into three main groups: systemic, topical, and others and CAM. Gabapentin, nalfurafine, acupuncture, and Chinese herbal bath therapy (CHBT) show antipruritic effects, with higher evidence grades in the meta-analysis. Emollients with additive compounds are more effective for reducing itch than emollients without additives. Supplements for deficient elements, such as zinc, omega-3, and omega-6, also show benefits for pruritus improvement. CAM therapies such as acupuncture, herbs, and herbal baths or creams all have good results for UP treatment. We summarize the treatments and suggest a treatment algorithm for UP according to severity. Some UP therapies are already supported by large-scale clinical evidence, and some new treatments can provide patients with new hope and treatment options. However, these new methods still need large population studies and further exploration.

Chronic Kidney Disease-Associated Pruritus: A Review

BACKGROUND

Chronic kidney disease-associated pruritus (CKD-aP), also known as uraemic pruritus, is a disabling symptom for patients and a challenging condition for clinicians. Despite being common amongst end-stage kidney disease (ESKD) patients, it remains underestimated and underdiagnosed. The exact pathogenesis remains largely elusive, which hampers the synthesis of a definite treatment approach.

SUMMARY

Chronic pruritus (lasting 6 weeks or more in duration) is a common and potentially disabling symptom in patients with advanced CKD. A unified hypothesis of pathogenesis has not yet been concluded. Studies have shown changes in the immunochemical milieu of the skin in patients with CKD-aP with several inciting stimuli identified. However, other unrecognized factors are likely to be involved. This article will review the current observations and understanding of the postulated pathogenesis of CKD-aP, as well as the evidence for current management strategies. Key Messages: CKD-aP is a common and troubling symptom amongst ESKD patients that is associated with decreased quality of life and poor prognosis. Its exact pathogenesis, at the time of writing, is not well-understood. A stepwise approach is recommended for management. Systematic reviews show the largest body of evidence was found for the effectiveness of gabapentin. Comparison is needed between newly emerging pharmacological agents such as kappa-opioid receptor agonists and more established agents, such as the gabapentinoids. Finally, renal transplantation should be considered in severe and refractory cases who are suitable transplant candidates as it has shown an excellent outcome in most cases.

Itching as the onset of pain (part 2)

Itching of the skin is a particularly unpleasant subjective sensation that causes the need to scratch. Physiological itching occurs in response to environmental irritants (friction, insect crawling, temperature changes, etc.) and disappears after elimination of the cause. Pathological itching is caused by changes in the skin or throughout the body and causes a strong need to get rid of itching by combing or any other method. Itching is a common symptom of local (dermatological) or general (systemic) disease. It can be limited (localized) or diffuse (generalized).One of the causes of itching is often noted endocrine diseases and metabolic disorders: hyper- and hypofunction of the thyroid gland, diabetes mellitus and hyperparathyroidism. In thyroid hyperfunction, generalized (inconstant and little-pronounced) itching of the skin is observed in the clinical picture only in 10 % of patients. It is accepted that itching of the skin in thyrotoxicosis syndrome is due to increased activity of kinin in combination with an increase in major metabolism and an increase in body and skin temperature (123).Itching caused by impaired bile secretion is characteristic of many diseases of the liver: primary biliary cirrhosis, sclerosing cholangitis, viral hepatitis caused by cholestasis medications and other causes of obstructive jaundice. It is in these cases that prurigo is usually generalized, but in some typical cases it is more pronounced on the feet and palms. With this pathology, itching is caused by obstruction of the biliary tract, however, and to this day, no close correlation has been found between serum bilirubin and the severity of itching.If it was previously thought that itching in pathology of the peripheral or central nervous system, such as multiple sclerosis, neuropathy, compression or irritation of nerves (e.g., paraesthetic dorsalgia, brachioradial itching) is also a significant symptom, then modern studies prove that in more cases, itching is not characteristic of most pathologies of the nervous system, so after a detailed anamnesis, examination and initial research, the patient should be referred to a related specialist, except in cases of about obvious postherpetic neuropathy, painless paresthesia, or brachioradial itching, which can often be guided in the provision of primary care.Instead, there are some psychological conditions and a number of psychiatric illnesses (obsessive-compulsive disorders, depression, and parasite illusions) that are most commonly diagnosed with the exclusion method. Neurotic squabbles are scattered on the body of the excorii, covered with scales that may occur in any area of the body that the patient may reach, but are often limited by limbs.

Development and Validation of a Uremic Pruritus Treatment Algorithm and Patient Information Toolkit in Patients With Chronic Kidney Disease and End Stage Kidney Disease

CONTEXT

Uremic pruritus (UP) affects up to half of all patients with kidney disease and has been independently associated with poor patient outcomes. UP is a challenging symptom for clinicians to manage as there are no validated guidelines for its treatment.

OBJECTIVES

The study aimed to develop and validate an algorithm and patient information toolkit for the treatment of UP in patients with kidney disease.

METHODS

The study involved a literature search and development of an initial draft algorithm, followed by content and face validation of this algorithm. Validation entailed three rounds of interviews with six nephrology clinicians per round. Participants assessed the relevance of each component of the algorithm and then rated a series of statements on a scale of 1-5 to assess face validity of the algorithm. After each round, the content validity index (CVI) of each algorithm component was calculated, and the algorithm was revised by the study team in response to findings. This process was followed by a second study that developed and validated a patient information pamphlet and video.

RESULTS

Algorithm validation participants were affiliated with three institutions and included seven physicians, four registered nurses, three nurse practitioners, three pharmacists, and a dietician. The average CVI of the algorithm components across all three rounds was 0.89, with 0.80 commonly cited as the lower acceptable limit for content validation. More than 78% of participants rated each face validity statement as "Agree" or "Strongly Agree". For the patient information tools, five clinicians and 15 patients were included in validation. The average CVI was 1.00 for both tools, and the average face validity was 92%.

CONCLUSION

A treatment algorithm and patient information toolkit for managing UP in patients with kidney disease were developed and validated through expert review. Further research will be conducted on implementation of the treatment algorithm and evaluating patient-reported outcomes.

Current treatment strategies in refractory chronic pruritus

Chronic pruritus is a highly prevalent, debilitating disease, which is often refractory to conventional therapies. A step-wise, guideline-driven approach should be adopted in the management of these patients. Emollients as well as topical corticosteroids if appropriate should be initiated whilst looking for the cause underlying the pruritus. If these measures fail, and the origin of the pruritus remains unknown, cannot be treated or does not respond to therapy, systemic therapies as for example gabapentinoids, antidepressants, mu-opioid-receptor antagonists or, in case of inflammatory conditions, immunosuppressive drugs should be recommended. Novel agents, especially systemic monoclonal antibodies, neurokinin-1 receptor antagonists and opioid receptor modulators, are promising in providing relief in refractory cases.

Epidemiology and determinants of pruritus in pre-dialysis chronic kidney disease patients

PURPOSE

There are only a few small studies investigating chronic kidney disease-associated pruritus (CKD-P) in pre-dialysis chronic kidney disease (CKD). None of these has taken into account the associations of CKD-P with clinical features and laboratory data. We aimed to study prevalence of and clinical and laboratory associates of CKD-P in pre-dialysis CKD patients.

METHODS

A total of 402 consecutive stage 2-5 pre-dialysis CKD patients were included in this cross-sectional study. Pruritus was scored based on visual analog scale (VAS). Demographic and clinical features, comorbidities, smoking status and current medication use were recorded. 25 (OH) Vitamin D, urea, creatinine, uric acid, calcium, phosphorus, intact parathyroid hormone (PTH), magnesium, albumin, C-reactive protein (CRP), complete blood count and differential and other laboratory tests were studied for each participant.

RESULTS

This is the largest study conducted in pre-dialysis population with respect to pruritus and associated factors. The prevalence of CKD-P was 18.9%. Hemoglobin level was significantly lower, and eosinophil count and frequency of xerosis cutis were significantly higher in patients with CKD-P than those of patients without pruritus. However, there was no statistical difference between the pruritus and nonpruritus groups regarding vitamin D, PTH, calcium, phosphorus, neutrophil-to-lymphocyte ratio (NLR) and CRP.

CONCLUSIONS

CKD-P was almost present in one in every five pre-dialysis CKD patients. Interestingly, the prevalence was not affected by the stage of the CKD. For the first time, our results showed a significant association between CKD-P and peripheral eosinophilia and anemia. Besides this, xerosis cutis seems a determinant factor for CKD-P and its severity.