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Query: UMLS:C0033774 (pruritus)
 14,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pruritus is a common manifestation of dermatologic diseases, including xerotic eczema, atopic dermatitis, and allergic contact dermatitis. Effective treatment of pruritus can prevent scratch-induced complications such as lichen simplex chronicus and impetigo. Patients, particularly elderly adults, with severe pruritus that does not respond to conservative therapy should be evaluated for an underlying systemic disease. Causes of systemic pruritus include uremia, cholestasis, polycythemia vera, Hodgkin's lymphoma, hyperthyroidism, and human immunodeficiency virus (HIV) infection. Skin scraping, biopsy, or culture may be indicated if skin lesions are present. Diagnostic testing is directed by the clinical evaluation and may include a complete blood count and measurement of thyroid-stimulating hormone, serum bilirubin, alkaline phosphatase, serum creatinine, and blood urea nitrogen levels. Chest radiography and testing for HIV infection may be indicated in some patients. Management of nonspecific pruritus is directed mostly at preventing xerosis. Management of disease-specific pruritus has been established for certain systemic conditions, including uremia and cholestasis.
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PMID:Pruritus. 1452 1

Itching is defined as an unpleasant cutaneous sensation leading to the desire to scratch. It serves as a physiological self-protective mechanism as do other cutaneous sensations like pain, touch, vibration, cold, and heat to help defend the skin against harmful external agents. Pruritus can be evoked in the skin directly by mechanical and thermal stimuli or indirectly through chemical mediators. It may also be generated in the central nervous system independently of peripheral stimulation. Single-nerve-fiber recordings have shown that histamine-evoked itch is transmitted by selective slow-conducting subpopulations of unmyelinated C-polymodal neurons. Recent experimental studies using improved methods have demonstrated which of the suspected chemical itch mediators such as histamine, neuropeptides, prostaglandins, serotonin, acetylcholine, or bradykinin act pruritogenically on C-fibers. Moreover, investigations have revealed new receptor systems such as vanilloid, opioid, and cannabinoid receptors on cutaneous sensory nerve fibers that may modulate itch and thereby represent targets for antipruritic therapy. This review focuses on the peripheral generation of itch, including neurotransmitters, neuropeptides, and inflammatory mediators.
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PMID:Neurophysiology of pruritus: cutaneous elicitation of itch. 1462 6

The antipruritic effects of the diets containing German chamomile on the compound 48/80-induced scratching in ddY mice were examined. Since it is reported that an injection of compound 48/80, but not histamine, induced scratching behaviour due to itch but not to pain in ddY mice (Kuraishi et al., 1995), compound 48/80-induced scratching in ddY mice seems to be a suitable parameter for evaluating antipruritic agents independent of histamine receptor antagonism. In the mice fed the diet containing 1.2 w/w % of the ethyl acetate extract of dried flower of German chamomile (Matricaria recutita L.) for 11 days, the compound 48/80-induced scratching behaviour was significantly suppressed. The ethyl acetate extract of German chamomile dose dependently suppressed compound 48/80-induced scratching without affecting body weight increase. The ethyl acetate fraction of the ethanol extract and the ethanol extract of hot water extraction residue of German chamomile flower also showed strong inhibition on the compound 48/80-induced scratching. The inhibitory effects of the dietary intake of the German chamomile extracts on compound 48/80-induced itch-scratch response were comparable to oxatomide (10 mg/kg, p.o.), an anti-allergic agent.
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PMID:Dietary intake of the flower extracts of German chamomile (Matricaria recutita L.) inhibited compound 48/80-induced itch-scratch responses in mice. 1469 26

Itch is a major symptom of skin disease and remains poorly studied. We have used limb-worn digital accelerometers, and infrared video of patients as a gold standard, on children with atopic dermatitis and control subjects in their own homes at night. Video analysis shows that nocturnal scratching and restlessness are more complex than we first thought, with many movements that potentially damage the skin not conforming to stereotypical scratch movements. Children with atopic dermatitis spent a mean of 46 minutes less time motionless or sleeping at night than control subjects (468 +/- 3 [SEM] vs 422 +/- 37 [SEM], P<.001). Children with atopic dermatitis showed 2 to 3 times as much scratching or restlessness activity as control subjects, with little overlap between groups (P<.01). Scratching and restlessness were highly correlated with each other (0.94, P<.01). Accelerometer scores were highly correlated with video results (rho>0.02, P<.01, for scratching, restlessness, and sleeping time). Individual limb scores were highly correlated with each other (rho approximately 0.87-0.98), suggesting that little information would be lost if only 1 limb was measured. There was little relation between parental assessment of scratch and objective measured scratch. Accelerometers provide a useful and practical way of assessing scratching at night in the patient's own home and could be used as an objective measure of disease activity both in clinical trials and in everyday clinical practice.
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PMID:The development of an objective method for measuring scratch in children with atopic dermatitis suitable for clinical use. 1469 62

The effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on experimental allergic conjunctivitis, induced by ocular challenge with antigen in actively sensitized guinea pigs, were investigated. NSAIDs reduced the increase in prostaglandin D2 (PGD2) and E2 (PGE2) in the ocular lavage fluid. The inhibition of NSAIDs to these increases was approximately 90%-95%. NSAIDs also lowered itch-scratch response (ISR) to approximately one-third to one-half of the vehicle-treated group. However, these drugs scarcely affected plasma exudation in the conjunctiva. Ketotifen, an H1 histamine receptor antagonist, inhibited both pathophysiological changes (inhibition: 70%-80%). However, this drug was less efficacious than NSAIDs in reducing PGD2 and PGE2 levels. Moreover, topical administration of histamine induced ISR and plasma exudation; in contrast, PGD2 induced ISR exclusively. These results suggest that a part of antigen-induced ISR may be attributable to PGs. However, PGs may not play a key role in plasma exudation; other mediators such as histamine may be involved.
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PMID:Effects of nonsteroidal anti-inflammatory drugs on experimental allergic conjunctivitis in Guinea pigs. 1473 14

Allergy to human seminal fluid is a rare but potentially life-threatening disorder. Acute symptoms range from local reactions to generalized symptoms. A 30-year-old woman experienced vulvovaginal itching, erythema and swelling as well as generalized urticaria and angioedema of the neck and face after unprotected sexual intercourse. A scratch test with undiluted seminal fluid and the detection of specific IgE antibodies revealed a type I allergy to seminal fluid. Risk factors and therapeutic options are discussed.
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PMID:[Type I sensitization to seminal fluid. Urticaria and angioedema]. 1474 70

Albumin dialysis has been shown to improve the outcome in patients with cholestatic liver failure caused by chronic liver disease. This study reports 7 liver transplant recipients who were treated with albumin dialysis for intractable pruritus of different origin (ductopenic graft rejection, non-anastomotic strictures, and recurrence of hepatitis C). Treatment with histamine (H1) blockers, opioid antagonists, and cholestyramine had not been effective. The Molecular Adsorbent Recirculating System (MARS; Teraklin, Rostock, Germany) was used for albumin dialysis. All patients presented with numerous scratch marks, 6 of whom had a pronounced icterus. Six patients (86%) responded to 3 consecutive treatments with significant reduction of pruritus. The mean pruritus score, which was quantified by a visual analog scale (VAS), decreased from 9.7 +/- 0.5 to 3.7 +/- 0.8 (SD). The mean duration of 1 treatment was 15.6 hours. The procedure was well tolerated by all patients. The mean total serum bilirubin in patients who responded to therapy declined from 19.11 +/- 16.96 mg/dL (SD) before MARS therapy to 9.24 +/- 3.52 mg/dL after treatment. The mean serum concentration of 3 alpha-hydroxy bile acids decreased from 192.67 +/- 58.12 micromol/L (SD) to 42.33 +/- 31.58 micromol/L (SD). Follow-up in 3 cases showed sustained improvement of pruritus lasting for more than 3 months. In 3 patients, however, pruritus relapsed. One patient, who showed severe pruritus, without relevant elevation of serum bile acids before treatment, did not respond to albumin dialysis. Our data indicate that MARS is an effective therapeutic option for patients with intractable cholestatic pruritus.
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PMID:Treatment of refractory cholestatic pruritus after liver transplantation with albumin dialysis. 1475 86

Lichen simplex chronicus (LSC) of the anogenital area is an eczematous disease characterized by unremitting itching and scratching. In most instances, it arises in individuals who are genetically atopic, and as such, LSC can be viewed as a localized variant of atopic/neurodermatitis. Common triggers for the development of the disease include psychological distress, and local environmental problems such as heat, sweating, and excess dryness. Lichen simplex chronicus may also develop as a superimposed condition in the presence of other anogenital diseases such as candidiasis, psoriasis, lichen sclerosus, tinea cruris, and neoplasia. Lichen simplex chronicus frequently persists as an itch-scratch cycle, even when environmental triggers are removed and the underlying disease is treated. For this reason, successful therapy requires attention not only to trigger factors, but also to repair of the damaged barrier layer, reduction in inflammation, and breakup of the itch-scratch cycle.
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PMID:Lichen simplex chronicus (atopic/neurodermatitis) of the anogenital region. 1475 86

Scabies is a global problem and a significant source of morbidity in nursing home residents and workers because of its highly contagious nature. It is also a problem in hospitals that care for the elderly, the debilitated, and the immunocompromised. New outbreaks continue to occur, despite controlling the recurrent epidemics. Scabies manifests as papules, pustules, burrows, nodules, and occasionally urticarial papules and plaques. Most of the patients with scabies experience severe pruritus. A subset of patients have crusted or Norwegian scabies. These patients, who are usually debilitated or immunocompromised, do not experience the urge to scratch, and therefore do not scratch their own skin. Diagnosis of scabies is based on patient history, physical examination, and demonstration of mites, eggs, or scybala (black or brown football-shaped masses of feces of scabies) on microscopic examination. Scabies can be treated with topical or oral therapies. Topical treatments include 5% permethrin cream, 1% lindane (gamma benzene hexachloride) lotion, 6% precipitated sulfur in petrolatum, crotamiton, malathion, allethrin spray, and benzyl benzoate. Ivermectin, the only oral treatment, is not approved for scabies in the US. Most authorities advocate using a scabicide several times, specifically once a week over a period of 2-3 weeks. In an outbreak of scabies in a nursing home, residents, staff, and frequent visitors should all be treated even if they are not symptomatic. Ivermectin is useful in treating patients with Norwegian or crusted scabies, or who are debilitated. Ivermectin has no serious reported adverse effects. Model treatment plans to stop scabies epidemics have been developed. These plans coordinate treatment of all persons exposed (including ivermectin for debilitated patients), isolation of infected patients, disinfection of objects that patients have come into contact with, and education and reassurance of the medical staff. Failure to coordinate notification, education, treatment, and disinfection leads to failure to control scabies epidemics. Control of epidemics of institutional scabies requires attention to treatment effects and logistics. Treatment is low risk, but cumbersome because many individuals need be treated. It is advisable to restrict, where possible, the number of staff members that deal with scabies patients to limit the spread of the scabies. Prolonged surveillance is required for the eradication of institutional scabies. While the foregoing plans require coordination of all involved personnel and sustained efforts, they are necessary to halt the spread of scabies to patients and staff, to enhance their morale, and to prevent deterioration of labor and public relations.
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PMID:Controlling scabies in institutional settings: a review of medications, treatment models, and implementation. 1497 41

Platelet-activating factor (PAF) plays important roles in allergic reactions. In particular, there are many concerns about PAF, eosinophils, and the chronicity of allergic diseases. The purpose of the present studies is to elucidate the role of PAF in eosinophil activation at conjunctiva and to confirm the efficacy of Apafant (a potent PAF antagonist) ophthalmic solution in chronic experimental allergic conjunctivitis. Guinea pigs were actively immunized and allergic conjunctivitis was induced by repetitive instillation of 2.5% ovalbumin. PAF solution was topically applied and eosinophil activation was assessed by measuring the eosinophil peroxidase (EPO) activity in the tear fluid. Itch-scratching episodes and clinical symptoms scores were evaluated in the repetitive challenge conjunctivitis. From the instillation of PAF solution into guinea pig eyes, which were in a state of chronic allergic conjunctivitis, a significant increase in EPO activity was observed, and this increase was inhibited by pre-treatment with Apafant. In the repetitive challenge model, the animals treated with Apafant ophthalmic solution showed a significant reduction of clinical symptoms and the itch-scratch response in both the first and the second challenges. PAF has an activity, that induces mediator release from eosinophils in the conjunctival tissues and may be involved in the chronic phase of allergic conjunctivitis.
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PMID:Apafant, a potent platelet-activating factor antagonist, blocks eosinophil activation and is effective in the chronic phase of experimental allergic conjunctivitis in guinea pigs. 1528 29


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