Psychiatric disorders and pruritus

Being female with vitiligo disease in traditional societies within North Africa

This study aims to assess the influence of vitiligo illness on the quality of life of female individuals residing in Ajdabiya, Libya. Through this investigation, we aim to enhance our comprehension of the potential impact of cultural norms and conventional gender roles on managing and caring for skin disorders within a North African society. Over a 20-week period, 65 female participants diagnosed with vitiligo were recruited. The participants' quality of life was assessed using the Skindex-16 scale. This validated tool measures the impact of skin disease on several aspects of an individual's life, including physical, emotional, and social well-being. The findings of this study indicate that the quality of life of women with vitiligo significantly differed with age, social and functional status, and economic status. However, the illness profoundly impacted patients' lives emotionally, with clear consequences, including diminished emotional satisfaction and reduced social participation. The results of this study highlight the negative effects that vitiligo disease can have on women's quality of life within traditional Libyan society. This investigation also indicates that cultural norms and traditional gender patterns may contribute to these effects.

CKD-Associated Pruritus and Clinical Outcomes in Nondialysis CKD

Rationale & Objective

Itching is a frequent symptom experienced by people with chronic kidney disease (CKD). We investigated the associations of CKD-associated pruritus (CKD-aP) with clinical outcomes.

Study Design

This was a longitudinal cohort study.

Setting & Participants

Patients from Brazil, France, and the United States enrolled in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) from 2013 to 2021, an international prospective cohort study of adults with nondialysis dependent CKD, and an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2 were included.

Exposure

CKD-aP was self-reported by response to the question: "During the past 4 weeks, to what extent were you bothered by itchy skin?"

Outcomes

The outcomes were as follows: CKD progression, kidney replacement therapy (KRT) initiation, mortality, hospitalization, cardiovascular events, infection events.

Analytical Approach

Associations with time-to-event outcomes were investigated using Cox proportional hazards models adjusted for potential confounders.

Results

There were 4,410 patients from 91 clinics with a median age of 69 years and a median eGFR at patient questionnaire completion of 29 (21-38) mL/min/1.73 m2. The proportion of patients not at all, somewhat, moderately, very much, and extremely bothered by itchy skin was 49%, 27%, 13%, 7%, and 3%, respectively. Patients with more advanced stages of CKD, older age, and greater comorbidities reported to be more likely bothered by itchy skin. Among patients at least moderately bothered, 23% were prescribed at least 1 pharmacotherapy (35% in the United States, 19% in France, 4% in Brazil), including antihistamine (10%), gabapentin (6%), topical corticosteroids (4%), pregabalin (3%), or sedating antihistamine (3%). The HR (95% CI) for patients extremely (vs not at all) bothered was 1.74 (1.11-2.73) for all-cause mortality, 1.56 (1.11-2.18) for all-cause hospitalization, and 1.84 (1.22-2.75) for cardiovascular events. As CKD-aP severity increased, patients also had higher rates of infection events (P = 0.04); CKD-aP severity was not associated with KRT initiation (P = 0.20) or CKD progression (P = 0.87).

Limitations

The limitations were 25% nonresponse rate, recall bias, and residual confounding factors.

Conclusions

These results demonstrate a strong association between severe itch and clinical outcomes, providing the nephrology community new insights into the possible adverse consequences of CKD-aP in individuals with nondialysis CKD, and warrant further exploration.

Plain-Language Summary

Chronic kidney disease-associated pruritus (CKD-aP) is a common disturbing symptom of chronic kidney disease (CKD). This article analyzes longitudinal data from the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) to describe prevalence of CKD-aP in 4,410 individuals with nondialysis CKD, and its association with clinical outcomes. We found that 51% of the surveyed population were bothered by pruritus. CKD-aP was more prevalent in those with more advanced stages of CKD, older age, and with more comorbid conditions. Compared to those not at all bothered by pruritus, those who were extremely bothered had a higher risk of all-cause mortality, hospitalizations, and cardiovascular events. Severity of CKD-aP was not associated with CKD progression or initiation of kidney replacement therapy.

Complementary and integrative remedies in the treatment of chronic pruritus: A review of clinical trials

BACKGROUND

Chronic pruritus is one of the most common conditions in dermatology and a common manifestation in many systemic diseases. Since the etiology of chronic pruritus remains somewhat unknown, hence, conventional medications may not always show a good therapeutic response. This finding has led both investigators and patients to use herbal and complementary remedies for its treatment. The aim of this study was to review clinical trials in which herbal and complementary medicine was used in the control and treatment of chronic pruritus.

MATERIALS AND METHODS

In this study, we reviewed related articles in this domain, from 2000 to 2020. The search involved electronic databases including PubMed, Scopus, Web of Science, Cochrane, Google Scholar, and SID databases using the keywords "pruritus," "itch," "herb," "complementary medicine," "traditional medicine," "integrative medicine," and their related MeSH terms. Finally, we extracted the pertinent information from these articles and summarized the results.

RESULTS

The findings of this study showed that 17 clinical trials have been conducted till date in order to evaluate the efficacy of herbal remedies and complementary medicines in the treatment of chronic pruritus. Herbal remedies including turmeric, Fumaria parviflora, Avena sativa, capsaicin, sweet almond oil, peppermint oil, violet oil, vinegar, as well as manual therapies including aromatherapy, auricular acupressure, and acupuncture, were significantly effective in the treatment of chronic pruritus.

CONCLUSION

There are only a few studies published on the therapeutic efficacy of herbal remedies and complementary medicine in the treatment of chronic pruritus. Some have shown promising results. Therefore, more evidence-based studies are needed in order to determine if herbal remedies and complementary medicine could be an effective alternative or adjuvant treatment modality in chronic pruritus.

Associations Between Atopic Dermatitis and Anxiety, Aggression, and Fear-Based Behaviors in Dogs

The goal of this study was to determine if anxiety, aggression, and fear-related behaviors are more common in pruritic dogs with atopic dermatitis than nonpruritic, healthy dogs. One hundred forty-one pruritic dogs >1 yr of age with a clinical diagnosis of atopic dermatitis and a >3 mo history of pruritus were recruited. Dog owners completed a behavioral survey (canine behavioral assessment and research questionnaire) and a pruritus scale (pruritus visual analog scale). Pruritic, atopic dogs showed significant increases in fear- and anxiety-related behaviors as well as aggression compared with a large control group of healthy dogs. Stranger-directed aggression, owner-directed aggression, familiar-dog aggression, dog-directed fear, nonsocial fear, touch sensitivity, excitability, and attention-seeking behaviors were all increased in the study group. Trainability was decreased in the study group. Chronically pruritic dogs experience fear and anxiety and are more likely to display aggression. This is an important welfare issue for these animals. Early recognition of the behavioral derangements that can be associated with chronic pruritic skin disease could allow early intervention with a multidisciplinary approach for these patients, thus improving patient and owner quality of life and long-term treatment outcomes.

The Effects of Cannabinoid Agonist, Heat Shock Protein 90 and Nitric Oxide Synthase Inhibitors on Increasing IL-13 and IL-31 Levels in Chronic Pruritus

BACKGROUND

Heat shock protein 90 (Hsp90) inhibitor and cannabinoid agonists ameliorate dry skin-induced chronic itch. We have recently reported that cannabinoids, hsp90 and nitric oxide (NO) are involved in dry skin-induced itch. Here, we investigated the contribution of the Th2 cell signaling pathway to the antipruritic effect of the hsp90 inhibitor 17-Alilamino-17-demethoxygeldanamycin (17-AAG), nitric oxide synthase (NOS) inhibitor Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) and cannabinoid agonist WIN 55,212-2 on a dry skin-induced scratch.

METHODS

Dry skin-induced chronic itching was created by topical application of AEW (acetone/diethyl ether/water). WIN 55,212-2 (1 mg/kg, i.p.), L-NAME (1 mg/kg, i.p.) and increasing doses of 17-AAG (1, 3 and 5 mg/kg,i.p.) were administered to Balb/c mice (for each group, n = 6). After these applications, skin tissues were taken from the nape region of all of the mice. Gene and protein expressions of IL-13 and IL-31 were evaluated in skin tissues by RT-PCR and immunohistochemistry, respectively.

RESULTS

IL-13 and IL-31 mRNA expressions and immune positive cell counts were increased in the AEW applied groups. WIN 55,212-2 reduced both of the increased cytokines levels, while L-NAME decreased only the IL-13. 17-AAG dose-dependently reduced the increased cytokine levels. IL-13 and IL-31 levels significantly decreased following the co-administration of these agents.

CONCLUSION

These results show that increased levels of IL-13 and IL-31 are associated with pruritus. Hsp90 inhibition and cannabinoid system activation may induce antipruritic effects through down-regulation of these cytokines.

Atopic dermatitis: Current standards of diagnosis and treatment, including the latest methods of management

Atopic dermatitis (AD) is a chronic relapsing disease which causes characteristic eczematous skin lesions. The most common symptoms of atopic dermatitis are persistent pruritus, xerosis, and skin lesions with a typical location and appearance that changes with the patient’s age. The prevalence of the disease in the pediatric population is estimated at 10% to 30%, while in adults it ranges from 1% to 3%. The number of people who suffer from AD is rising every year. The pathophysiology of the disease is complex and multifactorial. It involves elements of epidermal barrier dysfunction, alterations in cellular immune response, IgE hypersensitivity, and environmental factors. AD significantly reduces the quality of life of both patients and their families. Patients with AD are at higher risk for neuropsychiatric disorders such as depression, attention-deficit/hyperactivity disorder, and headaches. The decreased quality of life of AD patients and their families is associated with the discomfort of recurrent and chronic inflammatory skin lesions, persistent pruritus, and the inconvenience of long-term therapy. It also affects the psychological development of children, contributes to behavioral disorders (hyperactivity, hypersensitivity) and impacts many areas of family life such as sleep, leisure activities, and relationships between family members. The basic treatment of AD is avoidance of potential harmful factors, proper care in the treatment of exacerbations, topical corticosteroids, and calcineurin inhibitors in proactive therapy. In some patients who meet age criteria, phototherapy and cyclosporine should be considered. In individuals with severe AD who do not respond to topical treatment and who will not benefit from general therapy, dupilumab, a biologic drug, is the treatment of choice. Biologic treatment has an increasingly important place in the effective and modern therapy of AD. Currently, new biologic drugs are being researched, which may bring a therapeutic revolution in AD in the future. Allergen immunotherapy in patients with AD should be carefully evaluated on an individual basis, as proper selection of patients with documented IgE-dependent sensitization is important for the success of this therapy. Close collaboration with the patient and their caregivers, education, and psychological support as appropriate are integral to the treatment.

Epidemiological factors in patients with dermatologic conditions referring to the clinic of traditional Persian Medicine: A cross-sectional study

INTRODUCTION

Many patients with chronic diseases often use traditional medicine, as well as conventional medicine. The aim of this study was to evaluate the epidemiological factors of patients with dermatological conditions referring to traditional Persian Medicine (TPM) clinic.

MATERIALS AND METHODS

In this cross-sectional study, we reviewed all the patients' medical documents, from March 2018 to March 2019, with dermatological conditions referred to the TPM clinic at Shiraz, Southern Iran. Then, the epidemiological factors of the patients were recorded in a researcher-made data collection form. SPSS software version 22 was used to analyse the data.

RESULTS

Overall, 631 patients consisting of 151 (23.9%) males and 580 (76.1%) females were enrolled in the study. Most of the patients were aged from 31 to 40 years, 347 (55%) patients were married, and most of them were housewives. The frequency of patients in the spring was higher than in other seasons. Furthermore, most of the patients were university educated. Acne, eczema and hair loss were the three most complaints of the patients who were referred to the traditional medicine clinic. 301(47.7%) patients reported gastrointestinal problems as another complaint concomitant with their skin problems.

CONCLUSION

It seems that women with skin problems, including acne, eczema, and hair loss, were more likely to refer to the TPM clinic. Therefore, the development of TPM clinics in the dermatology field as a scientific and academic approach can be effective in the treatment of patients with dermatological conditions accompanied by traditional medicine.

UK psychodermatology services in 2019: service provision has improved but is still very poor nationally

BACKGROUND

Psychodermatology is an emerging subspeciality of dermatology. Psychodermatology clinics use a multidisciplinary approach to deal with psychological or psychiatric elements related to skin disease. Two previous studies in 2004 and 2012 highlighted the deficiency of psychodermatology services in the UK, despite the evidence that these services have high demand and are cost-effective.

AIMS

To reassess psychodermatology service provision in the UK and outline the developments that have been made.

METHODS

In conjunction with BBC Radio 5 Live, a survey questionnaire was distributed via email to the UK membership of the British Association of Dermatologists (BAD) and Psychodermatology UK. The survey consisted of 13 questions asking about the availability of psychodermatology services.

RESULTS

Basic percentages were used to analyse quantitative data, and content analysis was used for qualitative data. Our results showed that less than a quarter of the respondents (24%) have access to a nearby dedicated psychodermatology service. Additionally, the psychodermatology units do not have a unified configuration and clinical provision model differs nationally. Only around 5% of the clinicians have access to a clinic that provides psychology-dermatology-oncology service, and even fewer have access to a paediatric psychodermatology (4.8%). Engagement in psychodermatology research was reported by around 12% of the participants.

CONCLUSIONS

The psychocutaneous services in the UK have improved to some extent over the past decade; the service has become more widely available nationally, and the investment in research is promising. However, it is still insufficient and unable to fulfil patient demand, especially for vulnerable individuals such as children and dermato-oncology patients.

Affective Touch Reduces Electrically Induced Itch Experience

Introduction: Itch is a common symptom in dermatologic and other diseases and can have a severe impact on quality of life and mental health. As a proportion of patients with itch-symptoms is resistant to commonly used anti-histamine treatments, development of new treatments is desirable. Past research on pain, itch and affective touch (i.e. slow, gentle stroking of the skin activating C-tactile fibers) revealed an inhibitory relationship between affective touch and pain and between pain and itch. Given the overlap in neural processing between these three sensory submodalities, a possible interaction between affective touch and itch might be expected. This study investigated whether there is a relationship between itch and affective touch, and if so, whether affective touch inhibits itch.

Methodology: Itch was electrically induced with the use of electrodes that were placed at the ventral side of the wrist of 61 participants. A within-subject design was conducted with two conditions. An experimental -affective touch- condition (stroking the forearm with a soft brush at 3 cm/s) and a control -non-affective touch- condition (stroking the forearm with a soft brush at 18 cm/s). Touch was applied on the dorsal side of the forearm, the same arm as were the electrodes were placed. For each condition itch was induced for 20 min, with every 2 min a VAS-scale measurement of the level of experienced itch.

Results: Both types of touch reduced the experienced itch compared to baseline (p < 0.01, partial η² = 0.67). However, affective touch had an additional significant relieving effect compared to non-affective touch (p = 0.03, partial η²= 0.08). The alleviation of itch started after 2 min of stroking and continued to increase up till 6 min, where after the relieving effect stabilized but still persisted.

Conclusion: This finding suggest that affective touch, as with acute pain, has a relieving effect on electrically induced itch.

Interleukin-31 as a Clinical Target for Pruritus Treatment

In recent years, the published literature has suggested the key involvement of the cytokine interleukin-31 (IL-31) in the symptomatology of pruritus, and both IL-31 and its receptor have become potential therapeutic targets for a range of pruritic diseases. Elevated levels of IL-31 or its receptor have been reported in the tissue or serum of patients with pruritic skin diseases, such as atopic dermatitis, prurigo nodularis, and psoriasis. Pruritus places a heavy burden on patients, and can have a negative impact on daily life, sleep, and mental health. Since current anti-pruritic treatments are often ineffective, affected patients are in urgent need of new therapies. As a result, drug development targeting the IL-31 pathway is evolving rapidly. To date, only nemolizumab, a humanized monoclonal antibody targeting the IL-31 receptor, has successfully completed late-stage clinical studies. This article will highlight our current clinical understanding of the role of IL-31 in pruritic disease, and explore recent progress in drug development as well as the anticipated future advances in this field.

Pruriplastic Itch-A Novel Pathogenic Concept in Chronic Pruritus

The International Association for the Study of Pain (IASP) defined three descriptors for pain: nociceptive pain is “pain that arises from actual or threatened damage to non neural tissue and is due to the activation of nociceptors”; neuropathic pain is “pain caused by a lesion or disease of the somatosensory nervous system”; and nociplastic pain is “pain that arises from altered nociception despite no clear evidence of actual or threatened tissue damage causing the activation of peripheral nociceptors or evidence for disease or lesion of the somatosensory system causing the pain.” Based on clinical and pathophysiological arguments, a similar definition of “pruriplastic pruritus” should be made. Pruriplastic pruritus would include psychogenic pruritus, as well as some cases of pruritus ani, vulvar pruritus, sensitive skin or other poorly understood cases of pruritus. This new descriptor of itch could serve as systematic screening for altered pruriceptive function in patients who suffer from chronic itch and it may also help in defining better tailored treatment by identifying patients who are likely to respond better to centrally rather than to peripherally targeted therapies.

Itch processing in the brain

Itch is a sensation defined as the urge to scratch. The central mechanisms of itch are being increasingly studied. These studies are usually based on experimental itch induction methods, which can be classified into the following categories: histamine-induced, induction by other non-histamine chemicals (e.g. cowhage), physically induced (e.g. electrical) and mentally induced (e.g. audio-visual). Because pain has been more extensively studied, some extrapolations to itch can be proposed and verified by experiments. Recent studies suggest that the itch-processing network in the brain could be disrupted in certain diseases. This disruption could be related to the implication of new regions or the exclusion of already engaged brain regions from itch-processing network in the brain.

Management of Itch in the Elderly: A Review

Chronic itch is common in the elderly patient and may be caused by a variety of known dermatologic and non-dermatologic conditions and can have a significant effect on quality of life. Age-related changes in barrier function, immunosenescence, and neuronal changes and neuropathies are common predisposing factors to chronic itch in this age group. Certain primary dermatologic conditions are more common in the elderly and can cause chronic itch. Also, co-morbid diseases particularly of the renal, hepatobiliary, or hematologic systems, psychologic conditions, or medications may contribute to chronic itch in this population. Thus, medical workup for an elderly patient with chronic itch requires special attention to the patient's medical history, current health status, and medications. Topical treatments and emollients may be recommended for elderly patients, with consideration of specific adverse effects and alternatives. Systemic medications pose a higher risk of adverse effects and many are contraindicated in the elderly for this reason. In addition, management in the elderly may be complicated by differential pharmacokinetics of medications, the presence of co-morbid health conditions, cognitive disorders, physical limitations, and polypharmacy. New and emerging treatment modalities hold promise for use in the elderly due to these special considerations.

Racial and Gender Differences in the Presentation of Pruritus

Background: Pruritus is a common disease symptom with a variety of etiologies known to reduce patient quality of life. We aimed to characterize the racial and gender differences in the presentation of pruritus for itch-related patient visits both within a single institution and nationally. Methods: Cross sectional study of patients ≥ 18 years old seen at Johns Hopkins Health System between 1/1/12 and 1/1/18. Results were compared to data from 2005–2011 from the National Ambulatory Medical Care Survey (NAMCS) and the National Health Ambulatory Medical Care Survey (NHAMCS). Results: Our findings indicate that itch patients at JHHS (n = 18,753) were more likely to be black compared to white patients (37% vs. 19%, p < 0.01) when compared to patients without itch—a trend also noted nationally based on data from NAMCS/NHAMCS (26% vs. 21%, p = 0.05). Black itch patients are also more likely to be diagnosed with prurigo nodularis (OR 2.37, p < 0.0001), lichen planus (OR 1.22, p < 0.0001), and atopic dermatitis OR 1.51, p < 0.0001). Female itch patients are more likely to be diagnosed with autoimmune (OR 1.66, p < 0.0001) and psychiatric comorbidities (OR 1.2–1.8, p < 0.0001) than male itch patients. When compared to black itch patients nationally, white itch patients were more likely to visit a dermatologist (29% vs. 18%, p = 0.028). Our data can identify associated conditions and demographic differences but are unable to support a causal relationship. Conclusions: Black and female patients are more likely to present with pruritus, a symptom associated with comorbidities such as prurigo nodularis, lichen planus, atopic dermatitis, and psychiatric conditions.

Diagnostic Workup and Evaluation of Patients with Prurigo Nodularis

Prurigo nodularis (PN) is a chronic inflammatory skin disease characterized oftentimes by symmetrically distributed, severely pruritic nodules. Currently, the pathophysiology of PN remains to be fully elucidated, but emerging evidence suggests that neuroimmune alterations play principal roles in the pathogenesis of PN. There are several associated etiologic factors thought to be associated with PN, including dermatoses, systemic, infectious, psychiatric, and neurologic conditions. We conducted a systematic literature review to evaluate the clinical presentation, diagnosis, and etiologic factors of PN. In this review, we discuss common differential diagnoses of PN and recommend an evidence-based, standardized diagnostic evaluation for those with suspected PN.

Chronic itch impairs mood and HPA axis function in mice: modulation by CRFR1 antagonist

Chronic itch is clinically correlated with the development of mood disorders such as anxiety and depression. Nonetheless, whether this relevance exists in rodents is unknown, and evidence demonstrating chronic itch can affect mood is lacking. The aim of this study is to characterize the affective consequences of chronic itch, and explore potential mechanisms and interventional strategy. We subjected mice to chronic itch by repetitive cutaneous treatment with acetone and diethylether followed by water (AEW) that models "dry skin." After 3 to 4 weeks AEW treatment, the mice developed behavioral phenotypes of anxiety and depression assessed by a battery of behavioral paradigms, such as light-dark box and forced swim test. These behavioral symptoms of mood disturbance were independent of cutaneous barrier disruption, but correlated well with the degree of the irritating itch sensation. Although AEW mice showed normal circadian hypothalamic-pituitary-adrenal (HPA) axis activity, their neuroendocrine functionality was dampened, including impaired endocrine stress responsivity, altered neuroendocrine-immune interaction, and blunted corticosterone response to both dexamethasone and CRF. Parameters of HPA functionality at the level of mRNA transcripts are altered in stress-related brain regions of AEW mice, implying an overdrive of central CRF system. Remarkably, chronic treatment of AEW mice with antalarmin, a CRFR1 antagonist, ameliorated both their mood impairment and stress axis dysfunction. This is the first evidence revealing mood impairment, HPA axis dysfunction, and potential therapeutic efficacy by CRFR1 antagonist in mice with chronic itch, thus providing a preclinical model to investigate the affective consequence of chronic itch and the underlying mechanisms.

The behavioral study on the interactive aggravation between pruritus and depression

BACKGROUND

The interactive aggravation of pruritus and depression is well-known, but an appropriate experimental model that could mimic this behavioral phenomenon is still lacking. Thus, a systematic animal behavioral investigation was carried out in this study. This will promote the research and treatment of pruritus and depression.

METHODS

The 2,4-dinitrofluorobenzene (DNFB)-induced chronic itch model was established to measure the depression index by forced swimming test (FST), tail suspension test (TST), and splash test (ST). The chronic unpredicted mild stress (CUMS)-induced depression model was established to measure spontaneous itch and acute histamine or chloroquine-induced itch behaviors. A depression and itch combining model was also established to measure the scratching and depression behaviors. The motor function of DNFB mice was analyzed by the rotarod test.

RESULTS

The scratching number, the immobility time in the FST and TST, and the grooming number in the ST test were all significantly increased in the chronic itch model. Mice receiving CUMS treatment showed significantly increased spontaneous scratching number, immobility time in the FST and TST tests, and grooming number in the ST. The combined model showed increased immobility time in FST and TST tests and increased grooming number in ST comparing to the depression model, and showed increased scratching number comparing to the chronic itch model. After histamine (His) or chloroquine (CQ) injection, the scratching numbers of CUMS mice were all significantly increased compared to those of His- and CQ-control, respectively. Anti-depression drug ketamine could significantly inhibit the depression-like behaviors of CUMS mice, and simultaneously stopped the promoting effect on His-induced acute itch.

CONCLUSIONS

This study established an appropriate cross aggravation experimental mode and demonstrated that there is cross aggravation between pruritus and depression. The illumination of related mechanisms underlying this cross aggravation effect will provide theoretical basis for the prevention and treatment of depression and pruritus.

Antidepressants as antipruritic agents: A review

Pruritus is a concomitant symptom of various underlying disorders viz. dermatological, systemic and psychiatric disorders that provoke the person to scratch the skin. Many natural as well as, antipruritic therapies are usually practiced in the treatment of pruritus including general preventive measures, topical therapies such as cooling agents, antihistamines, anesthetics, capsaicin, corticosteroids, immunomodulators and; systemic therapies including administration of antihistamines, opioid antagonists/agonists, antiepileptic drugs/neuroleptics (e.g., gabapentin and pregabalin), antidepressants (e.g., doxepin, amitriptyline, paroxetine, fluvoxamine, sertraline, escitalopram and mirtazapine) (Patel and Yosipovitch, 2010; Reich et al., 2011; Martín and Padilla, 2015; Eskeland et al., 2016). Topical therapies are the mainstay of treatment of delicate and localized pruritus while other systemic drug therapies are used to treat stern and generalized pruritus. The reported antipruritic activity of some antidepressant drugs has intrigued this review to focus on the types of pruritus, pruritus mechanism, the antipruritic mechanism of antidepressants and to comprehend the role of antidepressants in the management of pruritus.

Psychogenic itch

Psychogenic itch can be defined as "an itch disorder where itch is at the center of the symptomatology and where psychological factors play an evident role in the triggering, intensity, aggravation, or persistence of the pruritus." The disorder is poorly known by both psychiatrists and dermatologists and this review summarizes data on psychogenic itch. Because differential diagnosis is difficult, the frequency is poorly known. The burden is huge for people suffering from this disorder but a management associating psychological and pharmacological approach could be very helpful. Classification, psychopathology, and physiopathology are still debating. New data from brain imaging could be very helpful. Psychological factors are known to modulate itch in all patients, but there is a specific diagnosis of psychogenic itch that must be proposed cautiously. Neurophysiological and psychological theories are not mutually exclusive and can be used to better understand this disorder. Itch can be mentally induced. Opioids and other neurotransmitters, such as acetylcholine and dopamine, are probably involved in this phenomenon.