Severe pruritus in a haemodialysed patient: dramatic improvement with granisetron

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.

Uremic Pruritus

Renal itch is a localized or generalized itch, affecting patients with chronic renal failure, where there is no primary skin disease and no systemic or psychological dysfunction that might cause pruritus. Uremic pruritus (UP) is an unpleasant sensation, rarely appearing in earlier stages of chronic kidney disease. Renal transplantation is the definite solution for that problem. The prevalence of UP has been reduced during the last years, possibly, due to a more efficient dialysis, with more biocompatible filters.

During the last decades a big number of substances were considered to be etiologic factors of UP, and an even bigger number of therapeutic substances appeared with promising potentials and conflicting results in the course of their use. The main reason for this disorientation is the lack of sound evidence on the pathogenetic mechanisms that may potentiate UP.

‘Inflammatory’ and ‘opioid’ hypothesis are the best studied and the reduction of UP is a fact. Nevertheless the mechanisms of the pathogenesis of UP are still under investigation and a long way has to be done in order to achieve more definite results.

Pruritus: management algorithms and experimental therapies

Pruritus (itch) is a major symptom in many dermatologic as well as systemic diseases and has a dramatic impact on the quality of life in these patients. The symptom of itch has to be treated on the basis of its pathophysiology and its underlying disease. In daily practice, a "quick" diagnosis of the underlying disease is often difficult, although a rapid relief of the itch is desired. We often treat patients on the basis of the symptomatology. A rational therapeutic ladder for a symptomatic therapy is useful until the final diagnosis has been confirmed. There are probably many subtypes of pruritus, just as there are many diseases that cause itch. The pathophysiology in many subtypes of pruritus is still poorly understood, hindering a rapid and targeted treatment strategy. An extensive diagnostic workup is often required to determine the final cause(s) of the itch. Thus, in daily life, physicians often start with a more or less rational therapeutic strategy to combat the debilitating itch. We present possible therapeutic ladders that form the basis for effective therapeutic itch strategies in various diseases. On the basis of our current knowledge about the different pathophysiologies of itch, on clinical trials or case reports, and our own clinical experience, we aim to present therapeutic ladders for the rapid as well as long-term management of itch. Finally, we summarize current exciting developments of experimental strategies in itch research and in clinical development for itch therapy.

Uraemic pruritus: clinical characteristics, pathophysiology and treatment

Pruritus is a common complication of end-stage renal disease (ESRD), affecting about one-third of dialysis patients. It is a chronic, unpleasant symptom with a strong negative impact on patients' quality of life, often inducing sleeplessness and mood disorders. Recent data show that it is also associated with increased mortality. The pathogenesis of uraemic pruritus (UP) is multifactorial. Triggering factors may include uraemia-related abnormalities (particularly involving calcium, phosphorus and parathyroid hormone metabolism), accumulation of uraemic toxins, systemic inflammation, cutaneous xerosis, and common co-morbidities such as diabetes mellitus and viral hepatitis. Recent findings suggest that the neurophysiology of itch is similar to that of pain; this has led to the hypothesis that the two phenomena also closely interact in ESRD patients, who often also experience uraemic neuropathy. The management of UP needs to address several different issues, such as optimization of dialysis efficacy and skin hydration, and correction of calcium-phosphorus metabolism abnormalities. A wide range of antipruritic drugs have been suggested for the treatment of UP, although most of them have only been tested in small, uncontrolled trials, which have yielded conflicting results. Antihistamines are now known to have little or no efficacy, although they are still often prescribed. Novel neurotropic drugs such as gabapentin, along with opioid receptor modulators such as nalfurafine, appear to be effective and well tolerated, but their efficacy has not yet been directly compared. Finally, physical therapies, including UV radiation, may also have a role in patients with refractory symptoms.

Antipruritic effects of two different 5-HT3 receptor antagonists and an antihistamine in haemodialysis patients

Pruritus is the most distressing symptom in haemodialysis (HD) patients. Its aetiology has not yet been delineated, and thus there are no good therapeutical options. Case reports and series attribute antipruritic potency to the serotonin receptor antagonists of the 5-HT3 type in renal pruritus. It was the aim of this study to investigate the antipruritic effect of two different 5-HT3 receptor antagonists and an antihistamine in 11 patients undergoing HD. Pruritus was induced by iontophoresis with serotonin and histamine and recorded before and after HD. These data were compared to those obtained after oral pretreatment with the 5-HT3 receptor antagonists tropisetron 5 mg and ondansetron 8 mg and the antihistamine cetirizine 10 mg. Ten healthy volunteers served as a control group. Vasocutaneous parameters (wheal and flare), skin temperature and alloknesis were also determined. Itching in HD patients and controls was not significantly diminished by oral pretreatment with the serotonin receptor antagonists. In controls, but not in HD patients, cetirizine significantly reduced itching, skin temperature and vasocutaneous parameters. Our data additionally demonstrate that there are no significant differences in vasocutaneous parameters, itching and alloknesis in HD patients before and after dialysis. We conclude that 5-HT3 receptor blockers such as tropisetron and ondansetron and the antihistamine cetirizine do not sufficiently reduce serotonin- and histamine-induced itching in haemodialyis patients.

Behandlung von Pruritus als Symptom von Hauterkrankungen mit dem Serotonin-Rezeptorantagonisten Ondansetron. Therapy of pruritus associated with skin diseases with the serotonin receptor antagonist ondansetron

BACKGROUND

Pruritus is often a stressing symptom and a therapeutic challenge. We report our experience with the serotonin receptor antagonist ondansetron in the symptomatic treatment of pruritus accompanying various skin diseases.

PATIENTS AND METHODS

The influence of ondansetron (8-12 mg orally per day) on pruritus was assessed in twelve patients with various skin disorders. The intensity of pruritus was quantitated daily by a visual analogue scale over the time period of one week before, during, and one week after treatment.

RESULTS

Ondansetron decreased pruritus intensity in prurigo simplex (four patients), asteatotic eczema (two patients), parapsoriasis en plaques, and pruritus of unknown origin (one patient each). One of two patients with atopic dermatitis experienced relief, whereas no benefit was observed in urticaria factitia and notalgia paraesthetica (one patient each).

CONCLUSIONS

Ondansetron may ameliorate the concomitant pruritus of some dermatologic diseases.