***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Purpose : Pruritus ani is a common and embarrassing proctological condition which can be very difficult to treat . We report the results of a double blind placebo controlled study of treatment with capsaicin . Methods : Firstly , a pilot open study was carried out on five patients to establish which of two doses was the most acceptable by comparing effectiveness and side effects . Secondly , a double blind , placebo controlled , crossover study of topical capsaicin was performed . This study involved two four week treatment phases separated by a one week washout phase . Forty four patients were r and omised to receive locally either active capsaicin ( 0.006 % ) or placebo ( menthol 1 % ) ointment over a four week period ( 22 patients per group ) . After four weeks of treatment and a one week washout period , the placebo group began to receive capsaicin while the treated group received placebo ( menthol 1 % ) for another four weeks . At the end of the controlled study , responders from both groups continued with capsaicin treatment in an open labelled manner . Results : Thirty one of 44 patients experienced relief during capsaicin treatment periods and did not respond to menthol ; all patients not responding to capsaicin also failed on menthol ( p<0.0001 ) . In 13 patients , treatment with capsaicin was unsuccessful : eight patients did not respond to capsaicin treatment , one responded equally to capsaicin and placebo , and four others dropped out because of side effects . During the follow up period ( mean 10.9 ( SD 5.8 ) months ) , 29 “ responders ” needed a mean application of capsaicin every day ( 1.6 ( SD 1.2 ) ; range 0.5–7 days ) to remain symptom free ( or nearly symptom free ) . Conclusion : Capsaicin is a new , safe , and highly effective treatment for severe intractable idiopathic pruritus ani Pruritus is a significant symptom among patients receiving hemodialysis . However , its underlying mechanisms remain obscure . Substance P , a neuropeptide , has been implicated in the mediation of pain and some itch sensations . Local application of capsaicin depletes the peripheral neurons of substance P and may block the conduction of pain or pruritus . This study aims to assess the efficacy and safety of capsaicin 0.025 % cream in the treatment of hemodialysis-related pruritus and to further explore the underlying pathomechanism . Nineteen hemodialysis patients with idiopathic , moderate ( n = 5 ) to severe ( n = 14 ) pruritus were examined in a double-blind , placebo-controlled , crossover study and 17 of them completed the study . Topical agent of capsaicin or placebo base cream was applied to localized areas of pruritus 4 times a day . The severity of pruritus and treatment-related side effects ( cutaneous burning/stinging sensations , dryness , or erythema ) were evaluated weekly . The results showed ( 1 ) that 14 of 17 patients reported marked relief and 5 of these 14 patients had complete remission of pruritus during capsaicin treatment ( Wilcoxon signed-ranks test , 2p < 0.001 ) ; ( 2 ) capsaicin was significantly more effective than placebo ( Mann-Whitney rank sum test , 2p < 0.001 ) and a prolonged antipruritic effect was observed 8 weeks posttreatment ; ( 3 ) no serious side effects were noted during the study and ( 4 ) there were no significant changes in serum concentrations of albumin , calcium , phosphorus , alkaline phosphatase , or intact parathyroid hormone during the treatment with either capsaicin or placebo . In summary , the present study indicates indirectly that idiopathic pruritus in some patients on maintenance hemodialysis may be transmitted by substance P from the peripheral sensory neurons to the central nervous system . Topical capsaicin with the unique pharmacological effect is demonstrated to markedly improve the pruritus of these patients INTRODUCTION Pruritus is one of the common problems in patients on hemodialysis . There are several causes for pruritus , and different treatment modalities are applied to control it . The aim of this study was to evaluate the therapeutic effect of capsaicin on pruritus , compared with placebo , in patients on hemodialysis . MATERIAL S AND METHODS This r and omized double-blinded cross-over clinical trial was performed on 34 patients on hemodialysis with uremic pruritus . The patients were divided into 2 groups , one group received capsaicin 0.03 % and the other , placebo , for 4 weeks . Treatment was stopped for 2 weeks as washout period and continued as a cross-over technique . Pruritus scores were analyzed and compared . RESULTS Thirty-four patients on long-term hemodialysis , 14 men and 20 women with a mean age of 57.0 + /- 18.6 years were studied . The mean of pruritus score before capsaicin treatment was 15.9 + /- 6.3 , which was reduced to 6.4 + /- 3.9 , 4.7 + /- 3.1 , 3.2 + /- 2.9 , and 2.5 + /- 2.5 on weeks 1 to 4 , respectively ( P < .001 ) . In the placebo group , pruritus score before treatment was 15.0 + /- 6.0 on average , and it was 11.7 + /- 5.8 , 9.4 + /- 5.9 , 7.9 + /- 5.5 , and 7.2 + /- 5.5 , respectively , on weeks 1 to 4 ( P < .001 ) . There was no significant difference in pruritus scores before the treatment between the two groups , but after each week , the difference was significant ( P < .001 ) . Repeated measurement test showed that decreasing in pruritus severity in the capsaicin group was more than that in the placebo group during treatment period ( P < .001 ) . CONCLUSIONS Capsaicin is a new safe and effective topical treatment for hemodialysis-induced pruritus in patients with end-stage renal disease Abstract Capsaicin ( trans -8-methyl- N -vanillyl-6-nonenamide ) is thought to produce analgesic and possibly also antipruritic effects when applied topically . Capsaicin 0.05 % was applied three times daily over a 5-day period to the same infrascapular region . The effects of the pretreatment upon the pruritogenic and wheal and flare reactions to subsequent histamine iontophoresis ( 20 mC ) were evaluated on the following day . The antipruritic effects of the pretreatment were compared with the effects of placebo pretreatment and no pretreatment .  Wheal and flare areas were evaluated planimetrically . Itch or pain were rated every minute over a 24-min period . The areas of alloknesis , i.e. the induction of perifocal itch sensation by usually nonitching ( e.g. mechanical ) stimuli , were also evaluated . In control subjects , but not in atopic eczema ( AE ) patients , capsaicin pretreatment significantly reduced the flare area . Compared with control subjects , AE patients showed a lack of alloknesis or significantly smaller areas of alloknesis in pretreated and nonpretreated skin . In control subjects , capsaicin pretreatment significantly reduced itch sensations compared with nonpretreated skin , whereas in AE patients no differences were seen . Itch sensations in capsaicin-pretreated skin were significantly lower in control subjects than in AE patients . We conclude that capsaicin does effectively suppress histamine-induced itching in healthy skin but has less effect in AE . The diminished itch sensations and the absence of alloknesis in atopic individuals indicate that histamine is not the key factor in itching in AE Capsaicin , which has been studied extensively as a treatment for itch and several chronic pain disorders , induces burning during the first week of therapy , causing a substantial percentage of patients to discontinue treatment prematurely . We examined whether pre-treatment with the topical anesthetic EMLA reduces the burning sensation induced by capsaicin and alters capsaicin effects on thermal sensation and pain thresholds . Healthy adult volunteers participated in the single-blind , 6-day study . After baseline measurement of warmth , cold pain and heat pain thresholds with a computerized thermal sensory analyzer , subjects applied EMLA thrice daily on one forearm and vehicle placebo on the other forearm , 60 min before applying capsaicin 0.075 % on both forearms . Subjects rated burning sensations 3 times a day throughout the study . After 1 and 5 days of thrice daily application of EMLA or vehicle followed by capsaicin , thermal sensory testing was repeated . Subjects rated burning sensations to the significantly less on the EMLA pre-treated forearm compared with the placebo pre-treated forearm during all 5 days of treatment ( p < 0.01 ) . Capsaicin with and without EMLA produced significant heat pain hyperalgesia and cold pain hypoalgesia after 1 day of treatment . After 5 days of treatment , heat pain hyperalgesia persisted on both forearms ; however , it was significantly less on the EMLA-treated forearm vs the vehicle-treated site ( p < 0.03 ) . Cold pain hypoalgesia persisted in both forearms . The warmth sensation threshold was significantly higher on the EMLA-pre-treated forearm after 1 and 5 days of treatment . In conclusion , pre-treatment with EMLA significantly reduced the burning sensation from capsaicin and attenuated heat hyperalgesia during treatment 
    Output:
    
Generalised itching ( not caused by systemic disease or skin lesions ) is quite a common symptom in pregnancy .