Nemolizumab with concomitant topical therapy in adolescents and adults with moderate-to-severe atopic dermatitis (ARCADIA 1 and ARCADIA 2): results from two replicate, double-blind, randomised controlled phase 3 trials.

BACKGROUND: Nemolizumab, an interleukin (IL)-31 receptor subunit α antagonist, inhibits the IL-31 pathway of itch and skin inflammation in atopic dermatitis. Two international phase 3 studies were done to assess the efficacy and safety of nemolizumab in atopic dermatitis. In this Article we report results for the 16-week initial treatment period of both trials. METHODS: ARCADIA 1 and ARCADIA 2 were identical 48-week randomised, double-blind, placebo-controlled phase 3 trials in adult and adolescent participants (aged ≥12 years) with moderate-to-severe atopic dermatitis, associated pruritus, and inadequate response to topical steroids. Participants were enrolled from 281 clinics, hospitals, and academic centres in 22 countries across both trials, and were randomly assigned (2:1) to receive nemolizumab 30 mg subcutaneously (baseline loading dose 60 mg) or matching placebo once every 4 weeks with background topical corticosteroids (TCS) with or without topical calcineurin inhibitors (TCI; ie, TCS-TCI background treatment). Randomisation was done via interactive response technology and stratified by baseline disease and pruritus severity. Study staff and participants were masked throughout the study, with outcome assessors masked until database lock. Coprimary endpoints at week 16 post-baseline were Investigator's Global Assessment (IGA) success (score of 0 [clear skin] or 1 [almost clear skin] with a ≥2-point improvement from baseline) and at least 75% improvement in Eczema Area and Severity Index score from baseline (EASI-75 response). Outcome rates were compared between groups with the Cochran-Mantel-Haenszel test adjusting for randomisation strata. The key secondary endpoints were the proportion of participants with Peak Pruritus Numerical Rating Scale (PP-NRS) score improvement of at least 4 points at weeks 1, 2, 4, and 16; PP-NRS score below 2 at weeks 4 and 16; Sleep Disturbance Numerical Rating Scale score improvement of at least 4 points at week 16; EASI-75 response plus PP-NRS score improvement of at least 4 points at week 16; and IGA success plus PP-NRS score improvement of at least 4 points at week 16. Efficacy analyses were done on an intention-to-treat basis; safety analyses included all participants who received one dose of nemolizumab or placebo. Both studies are completed (ClinicalTrials.gov: ARCADIA 1, NCT03985943 and ARCADIA 2, NCT03989349). FINDINGS: Between Aug 9, 2019, and Nov 2, 2022, 1728 participants were enrolled across both trials: 1142 were allocated to nemolizumab plus TCS-TCI (620 in ARCADIA 1 and 522 in ARCADIA 2) and 586 to placebo plus TCS-TCI (321 in ARCADIA 1 and 265 in ARCADIA 2). ARCADIA 1 included 500 (53%) male participants and 441 (47%) female participants, and ARCADIA 2 included 381 (48%) male participants and 406 (52%) female participants. Mean age ranged from 33·3 (SD 15·6) years to 35·2 (17·0) years across the treatment groups. Both trials met the coprimary endpoints; at week 16, a greater proportion of participants receiving nemolizumab plus TCS-TCI versus placebo plus TCS-TCI had IGA success (ARCADIA 1: 221 [36%] of 620 vs 79 [25%] of 321, adjusted percentage difference 11·5% [97·5% CI 4·7-18·3], p=0·0003; ARCADIA 2: 197 [38%] of 522 vs 69 [26%] of 265, adjusted difference 12·2% [4·6-19·8], p=0·0006) and an EASI-75 response (ARCADIA 1: 270 [44%] vs 93 [29%], adjusted difference 14·9% [7·8-22·0], p<0·0001; ARCADIA 2: 220 [42%] vs 80 [30%], adjusted difference 12·5% [4·6-20·3], p=0·0006). Significant benefits were observed with nemolizumab for all key secondary endpoints including improvement in itch, as early as week 1, and sleep improvement by week 16. The safety profile was similar between nemolizumab plus TCS-TCI and placebo plus TCS-TCI. In the safety sets, 306 (50%) of 616 participants (ARCADIA 1) and 215 (41%) of 519 participants (ARCADIA 2) who received nemolizumab plus TCS-TCI had at least one treatment-emergent adverse event (serious treatment-emergent adverse events in six [1%] and 13 [3%], respectively); and 146 (45%) of 321 (ARCADIA 1) and 117 (44%) of 263 (ARCADIA 2) who received placebo plus TCS-TCI had at least one treatment-emergent adverse event (serious treatment-emergent adverse events in four [1%] and three [1%], respectively). Ten serious treatment-emergent adverse events possibly related to nemolizumab were reported in five (1%) participants in ARCADIA 2. No deaths occurred. INTERPRETATION: Nemolizumab plus TCS-TCI was efficacious and showed statistically and clinically significant improvements in inflammation and itch in adults and adolescents with moderate-to-severe atopic dermatitis. Nemolizumab might offer a valuable extension of current therapies if approved. FUNDING: Galderma.

Stable Response and Sustained Improvement of Itch and Sleep Symptoms in Patients with Atopic Dermatitis Treated with Lebrikizumab over 52 Weeks.

BACKGROUND: Lebrikizumab demonstrated significant improvement versus placebo for measures of skin clearance and patient-reported outcomes at weeks 16 and 52 in patients with moderate-to-severe atopic dermatitis (AD). We report the sustained impact of lebrikizumab monotherapy, over 52 weeks and between visits, on the frequency of itch and sleep loss symptoms, as assessed by Patient-Oriented Eczema Measure (POEM), in patients with moderate-to-severe AD. METHODS: In ADvocate1 and ADvocate2, Week-16 lebrikizumab responders (EASI75 or IGA 0/1 with ≥ 2-point improvement and without rescue medication) were randomized to lebrikizumab every 2 weeks (Q2W), every 4 weeks (Q4W), or placebo for 36 weeks. This pooled analysis reports improvement from Week 16 to 52 in patients achieving POEM response 0 (no days) or 1 (1-2 days) for Items 1 (itch) and 2 (sleep disturbance) for the lebrikizumab Q2W and Q4W treatment arms. Observed (excluding data collected after treatment discontinuation, rescue medication use, or patient transfer to escape arm) results were reported. RESULTS: At Week 16, for lebrikizumab Q2W and Q4W, 35.9% (n = 37/103) and 39.3% (n = 42/107) of patients responded 0 or 1 to Item 1 of POEM (Itch) and 12.6% (n = 13/103) and 12.1% (n = 13/107) responded 0. A total of 66.0% (n = 68/103) and 72.6% (n = 77/106) of patients responded 0 or 1 to Item 2 of POEM (Sleep) and 37.9% (n = 39/103) and 44.3% (n = 47/106) responded 0, respectively. By Week 52, for lebrikizumab Q2W and Q4W, 44.6% (n = 29/65) and 48.0% (n = 36/75) responded 0 or 1 to Item 1 of POEM (Itch), and 21.5% (n = 14/65) and 18.7% (n = 14/75) of patients responded 0. A total of 83.1% (n = 54/65) and 78.4% (n = 58/74) responded 0 or 1 to Item 2 of POEM (Sleep), and 67.7% (n = 44/65) and 59.5% (n = 44/74) responded 0, respectively. CONCLUSION: Weekly POEM responses for itch and sleep disturbance remained stable between doses and visits, and continued to improve from Week 16 through 52, in lebrikizumab-treated patients, demonstrating consistent improvement over time for key AD symptoms. TRIAL REGISTRATION NUMBERS: ADvocate1 (NCT04146363) and ADvocate2 (NCT04178967).

Phase 3 Trial of Nemolizumab in Patients with Prurigo Nodularis.

BACKGROUND: Prurigo nodularis is a chronic, debilitating, and severely pruritic neuroimmunologic skin disease. Nemolizumab, an interleukin-31 receptor alpha antagonist, down-regulates key pathways in the pathogenesis of prurigo nodularis. METHODS: In this phase 3, double-blind, multicenter, randomized trial, we assigned adults with moderate-to-severe prurigo nodularis to receive an initial 60-mg dose of nemolizumab followed by subcutaneous injections of 30 mg or 60 mg (depending on baseline weight) every 4 weeks for 16 weeks or matching placebo. The primary end points were an itch response (a reduction of ≥4 points on the Peak Pruritus Numerical Rating Scale [PP-NRS; scores range from 0 to 10, with higher scores indicating more severe itch]) and an Investigator's Global Assessment (IGA) response (a score of 0 [clear] or 1 [almost clear] on the IGA [scores range from 0 to 4] and a reduction from baseline to week 16 of ≥2 points). There were five key secondary end points. RESULTS: A total of 274 patients underwent randomization; 183 were assigned to the nemolizumab group, and 91 to the placebo group. Treatment efficacy was shown with respect to both primary end points at week 16; a greater percentage of patients in the nemolizumab group than in the placebo group had an itch response (56.3% vs. 20.9%; strata-adjusted difference, 37.4 percentage points; 95% confidence interval [CI], 26.3 to 48.5), and a greater percentage in the nemolizumab group had an IGA response (37.7% vs. 11.0%; strata-adjusted difference, 28.5 percentage points; 95% CI, 18.8 to 38.2) (P<0.001 for both comparisons). Benefits were observed for the five key secondary end points: itch response at week 4 (41.0% vs. 7.7%), PP-NRS score of less than 2 at week 4 (19.7% vs. 2.2%) and week 16 (35.0% vs. 7.7%), and an improvement of 4 or more points on the sleep disturbance numerical rating scale (range, 0 [no sleep loss] to 10 [unable to sleep at all]) at week 4 (37.2% vs. 9.9%) and week 16 (51.9% vs. 20.9%) (P<0.001 for all comparisons). The most common individual adverse events were headache (6.6% vs. 4.4%) and atopic dermatitis (5.5% vs. 0%). CONCLUSIONS: Nemolizumab monotherapy significantly reduced the signs and symptoms of prurigo nodularis. (Funded by Galderma; ClinicalTrials.gov number, NCT04501679; EudraCT number, 2019-004789-17.).

Perceived Stigmatization among Dermatological Outpatients Compared with Controls: An Observational Multicentre Study in 17 European Countries.

Perceived stigmatization places a large psychosocial burden on patients with some skin conditions. Little is known about the experience of stigmatization across a wide range of skin diseases. This observational cross-sectional study aimed to quantify perceived stigmatization and identify its predictors among patients with a broad spectrum of skin diseases across 17 European countries. Self-report questionnaires assessing perceived stigmatization and its potential predictors were completed by 5,487 dermatology outpatients and 2,808 skin-healthy controls. Dermatological diagnosis, severity, and comorbidity were clinician-assessed. Patients experienced higher levels of perceived stigmatization than controls (p < 0.001, d = 0.26); patients with psoriasis, atopic dermatitis, alopecia, and bullous disorders were particularly affected. Multivariate regression analyses showed that perceived stigmatization was related to sociodemographic (lower age, male sex, being single), general health-related (higher body mass index, lower overall health), disease-related (higher clinician-assessed disease severity, presence of itch, longer disease duration), and psychological (greater distress, presence of suicidal ideation, greater body dysmorphic concerns, lower appearance satisfaction) variables. To conclude, perceived stigmatization is common in patients with skin diseases. Factors have been identified that will help clinicians and policymakers to target vulnerable patient groups, offer adequate patient management, and to ultimately develop evidence-based interventions.

Narrowband-ultraviolet B vs Broadband-ultraviolet B in Treatment of Chronic Pruritus: A Randomized, Single-blinded, Non-inferiority Study.

Narrowband-ultraviolet B has shown increased efficacy over broadband-ultraviolet B in pruritic skin diseases, such as psoriasis and atopic dermatitis. In patients with chronic pruritus, e.g. in end-stage renal disease, broadband-ultraviolet B is recommended, but narrowband-ultraviolet B has also shown efficacy in reducing pruritus. This randomized, single blinded, non-inferiority study investigated the effects of narrowband-ultraviolet B compared with broadband-ultraviolet B. Patients with chronic pruritus were treated with either broadband- or narrowband-UVB 3 times a week for 6 weeks and clinical response was monitored. Pruritus, sleep disturbance, and the patients' subjective overall response to treatment were evaluated by the patients on a visual analogue scale (0-10). Skin excoriations were evaluated by investigators on a 4-point scale (0-3). Both phototherapeutic modalities showed significant antipruritic activity (itch reduction 48% and 66.4%, respectively) by broadband-ultraviolet B and narrowband-ultraviolet B. Narrowband-ultraviolet B proved to be not inferior to broadband-ultraviolet B in treating pruritus in patients with chronic pruritus, assuming a 20% non-inferiority margin.

S2k guideline: Diagnosis and treatment of chronic pruritus.

Pruritus is a cross-disciplinary leading symptom of numerous diseases and represents an interdisciplinary diagnostic and therapeutic challenge. In contrast to acute pruritus, chronic pruritus (CP) is a symptom of various diseases that is usually difficult to treat. Scratching and the development of scratch-associated skin lesions can alter the original skin status. In the presence of an itch-scratch-cycle, even secondary diseases such as chronic prurigo can develop. Chronic pruritus leads to considerable subjective suffering of those affected, which can result in restrictions on the health-related quality of life such as sleep disturbances, anxiety, depressiveness, experience of stigmatization and/or social withdrawal up to clinically relevant psychic comorbidities. Medical care of patients should therefore include (a) interdisciplinary diagnosis and therapy of the triggering underlying disease, (b) therapy of the secondary symptoms of pruritus (dermatological therapy, sleep promotion, in the case of an accompanying or underlying psychological or psychosomatic disease an appropriate psychological-psychotherapeutic treatment) and (c) symptomatic antipruritic therapy. The aim of this interdisciplinary guideline is to define and standardize the therapeutic procedure as well as the interdisciplinary diagnosis of CP. This is the short version of the updated S2k-guideline for chronic pruritus. The long version can be found at www.awmf.org.

Body dysmorphia in common skin diseases: results of an observational, cross-sectional multicentre study among dermatological outpatients in 17 European countries.

BACKGROUND: Body dysmorphic disorder (BDD) is a common psychiatric disorder associated with high costs for healthcare systems as patients may repeatedly ask for different, often not effective, interventions. BDD symptoms are more prevalent in patients with dermatological conditions than in the general population, but there are no large sample studies comparing the prevalence of BDD symptoms between patients with dermatological conditions and healthy skin controls. OBJECTIVES: To compare the prevalence of BDD symptoms between patients with different dermatological conditions and healthy skin controls and to describe sociodemographic, physical and psychological factors associated with BDD symptoms to identify patients who may have a particularly high chance of having this condition. METHODS: This observational, cross-sectional, comparative multicentre study included 8295 participants: 5487 consecutive patients with different skin diseases (56% female) recruited among dermatological outpatients at 22 clinics in 17 European countries, and 2808 healthy skin controls (66% female). BDD symptoms were assessed by the Dysmorphic Concern Questionnaire. Sociodemographic data and information on psychological factors and physical conditions were collected. Each patient was given a dermatological diagnosis according to ICD-10 by a dermatologist. The study was registered with number DRKS00012745. RESULTS: The average participation rate of invited dermatological patients was 82.4% across all centres. BDD symptoms were five times more prevalent in patients with dermatological conditions than in healthy skin controls (10.5% vs. 2.1%). Patients with hyperhidrosis, alopecia and vitiligo had a more than 11-fold increased chance (adjusted Odds Ratio (OR) > 11) of having BDD symptoms compared with healthy skin controls, and patients with atopic dermatitis, psoriasis, acne, hidradenitis suppurativa, prurigo and bullous diseases had a more than sixfold increased chance (adjusted OR > 6) of having BDD symptoms. Using a logistic regression model, BDD symptoms were significantly related to lower age, female sex, higher psychological stress and feelings of stigmatization. CONCLUSIONS: Clinical BDD symptoms are significantly associated with common dermatological diseases. As such symptoms are associated with higher levels of psychological distress and multiple unhelpful consultations, general practitioners and dermatologists should consider BDD and refer patients when identified to an appropriate service for BDD screening and management.

Long-Term Course of Polymorphic Light Eruption: A Registry Analysis.

Background: Little is known about the long-term course of polymorphic light eruption (PLE). Objective: To predict disease course, a questionnaire was sent to patients whose PLE had been diagnosed between March 1990 and December 2018 and documented in the Austrian Cooperative Registry for Photodermatoses. Methods: In January 2019, 205 PLE patients were contacted by mail and asked to complete a questionnaire on their disease course, including whether the skin's sun sensitivity had normalized (i.e., PLE symptoms had disappeared), improved, stayed the same, or worsened over time. Patients who reported normalization of sun sensitivity were asked to report when it had occurred. Results: Ninety-seven patients (79 females, 18 males) returned a completed questionnaire. The mean (range) duration of follow-up from PLE onset was 29.6 (17-54) years for females and 29.4 (16-47) years for males. The disease disappeared in 32 (41%) females after 17.4 (2-41) years and in 4 (24%) males after 11.8 (5-26) years. Twenty-nine (37%) females and 6 (35%) males reported improvement of symptoms over time; 15 females (19%) and 7 males (41%) reported no change; and 3 females (4%) and no males reported worsening of symptoms. Kaplan-Meier analysis revealed that after 20 years 74% (95%CI, 64-82%) of patients still suffered from PLE. PLE lesion persistence (>1 week) tended to predict a prolonged course of PLE. Conclusions: PLE usually takes a long-term course over many years though in most patients its symptoms improve or disappear over time. How improvement relates to the pathophysiology of the disease remains to be determined.

Itch in Atopic Dermatitis - What Is New?

Atopic dermatitis (AD) is among the most frequent inflammatory skin diseases in humans, affecting up to 20% of children and 10% of adults in higher income countries. Chronic pruritus is a disease-defining symptom of AD, representing the most burdensome symptom for patients. Severe chronic pruritus causes significant sleep disturbances and impaired quality of life, as well as increased anxiety, depression and suicidal behavior. Until recently, skin care, topical corticosteroids, and calcineurin-inhibitors were primarily used to treat mild to moderate AD, while phototherapy and immunosuppressive agents such as corticosteroids, cyclosporine, and methotrexate were used to treat patients with moderate to severe AD. The potential short- and long-term adverse events associated with these treatments or their insufficient therapeutic efficacy limited their use in controlling pruritus and eczema in AD patients over longer periods of time. As our understanding of AD pathophysiology has improved and new systemic and topical treatments have appeared on the market, targeting specific cytokines, receptors, or their intracellular signaling, a new era in atopic dermatitis and pruritus therapy has begun. This review highlights new developments in AD treatment, placing a specific focus on their anti-pruritic effects.

Itch in Hymenoptera Sting Reactions.

Insect stings and the resulting itch are a ubiquitous problem. Stings by members of the insect order Hymenoptera, which includes sawflies, wasps, bees and ants, and especially by bees and wasps are extremely common, with 56-94% of the population being stung at least once in their lifetime. The complex process of venom activity and inflammation causes local reactions with pain and pruritus, sometimes anaphylactic reactions and more seldomly, as in case of numerous stings, systemic intoxication. We reviewed the literature regarding itch experienced after Hymenoptera stings, but found no study that placed a specific focus on this topic. Hymenoptera venoms are composed of many biologically active substances, including peptide toxins and proteinaceous toxins. Peptide toxins from bee venom cause cell lysis and ion channel modulation in the peripheral and central nervous systems, while toxins from wasp venom induce mast cell degranulation and chemotaxis of polymorphonuclear leukocytes in the skin. The proteinaceous toxins cause a disruption of the cell membranes and necrotic cell death, degradation of hyaluronan (an extracellular matrix glycosaminoglycan), increased vascular permeability, hemolysis, as well as activated platelet aggregation. Mediators which could be directly involved in the venom-induced pruritus include histamine and tryptase released from mast cells, interleukin-4 and interleukin-13 from Th2 lymphocytes, as well as leukotriene C4. We postulate that a pruriceptive itch is induced due to the pharmacological properties of Hymenoptera venoms.

Chronic Nodular Prurigo: A European Cross-sectional Study of Patient Perspectives on Therapeutic Goals and Satisfaction.

Chronic nodular prurigo is characterized by recalcitrant itch. Patient perspectives on therapeutic goals, satisfaction with therapy and efficacy of therapeutic regimens for this condition are unknown. This questionnaire study examined these issues in 406 patients with chronic nodular prurigo from 15 European dermatological centres. Improvements in itch, skin lesions and sleep were the most important goals. Emollients, topical corticosteroids and antihistamines were the most frequently used treatments, while a minority of patients were prescribed potent medications, such as systemic immunosuppressants and gabapentinoids. Most patients were not satisfied with their previous therapy (56.8%), while 9.8% did not receive any therapy despite having active disease. A substantial number of respondents (28.7%) considered none of the therapeutic options effective. Although chronic nodular prurigo is a severe disease, most patients were not treated with potent systemic drugs, which may contribute to the high levels of dissatisfaction and disbelief in available therapies. Specific guidelines for chronic nodular prurigo and the development of novel therapies are necessary to improve care.

Quality of Life, Anxiety, and Depression in Patients With Early-Stage Mycosis Fungoides and the Effect of Oral Psoralen Plus UV-A (PUVA) Photochemotherapy on it.

Background: Little is known about psychological discomfort and quality of life (QoL) in early stage mycosis fungoides (MF) and the effect of psoralen plus UV-A (PUVA) on it. Objective: To evaluate QoL, anxiety, and depression with validated instruments in early stage MF patients and whether PUVA treatment improves it. Methods: Patients with stage IA to IIA MF were treated with PUVA twice weekly for 12-24 weeks, followed by maintenance treatment or not, in a prospective randomized clinical trial. Patients completed a questionnaire on DLQI as well as the Hospital Anxiety and Depression Scale (HADS) prior to therapy, after their last PUVA exposure, and after the PUVA maintenance or observance phase. Results: For 24 patients with early stage MF, completed questionnaires were available and analyzed. Prior to treatment, 17% reported strong (DLQI > 10) and 29% moderate impairment (DLQI 6-10) in QoL; 33% of patients reported HADS scores indicating anxiety, and 21% reported scores indicating depression. PUVA significantly improved overall QoL by reducing mean DLQI scores by 58.6% (p = 0.003), HADS-A by 30% (p = 0.045), and HADS-D by 44% (p = 0.002). Improvements in QoL and psychological well-being seemed to be sustained, irrespective of maintenance treatment or not. Limitations: Small sample size. Conclusions: PUVA sustainably improves QoL and psychological well-being in patients with early stage MF. Clinical trial registration: ClinicalTrials.gov identifier: NCT01686594.

Trial of Nemolizumab in Moderate-to-Severe Prurigo Nodularis.

BACKGROUND: Prurigo nodularis is a chronic pruritic skin disease with multiple nodular skin lesions. Nemolizumab is a monoclonal antibody targeting the interleukin-31 receptor, which is involved in the pathogenesis of prurigo nodularis. METHODS: We conducted a 12-week, randomized, double-blind, phase 2 trial of nemolizumab (at a dose of 0.5 mg per kilogram of body weight) administered subcutaneously at baseline, week 4, and week 8, as compared with placebo, in patients with moderate-to-severe prurigo nodularis and severe pruritus. Moderate-to-severe prurigo nodularis was defined as 20 or more nodules, and severe pruritus was defined as a mean score of at least 7 for the worst daily intensity of pruritus on the numerical rating scale (scores range from 0 [no itch] to 10 [worst itch imaginable]). The primary outcome was the percent change from baseline in the mean peak score for pruritus on the numerical rating scale at week 4. Secondary outcomes included additional measures of itching and disease severity. Safety assessments were performed through week 18. RESULTS: A total of 70 patients were randomly assigned in a 1:1 ratio to receive nemolizumab (34 patients) or placebo (36). The initial pruritus score on the numerical rating scale was 8.4 in each group. At week 4, the peak pruritus score on the numerical rating scale was reduced from baseline by 4.5 points (change, -53.0%) in the nemolizumab group, as compared with a reduction of 1.7 points (change, -20.2%) in the placebo group (difference, -32.8 percentage points; 95% confidence interval, -46.8 to -18.8; P<0.001). Results for secondary outcomes were in the same direction as for the primary outcome. Nemolizumab was associated with gastrointestinal symptoms (abdominal pain and diarrhea) and musculoskeletal symptoms. CONCLUSIONS: Nemolizumab resulted in a greater reduction in pruritus and severity of skin lesions than placebo in patients with prurigo nodularis but was associated with adverse events. Larger and longer trials are needed to determine the durability and safety of nemolizumab for the treatment of prurigo nodularis. (Funded by Galderma; ClinicalTrials.gov number, NCT03181503.).

Is there still a role for UV therapy in itch treatment?

Itching is a frequent and greatly distressing symptom related to many skin and systemic diseases. New insights into the pathophysiology of itchy skin and potentially involved mediators have increased the interest in and development of new treatments that specifically act on targets involved in the transmission and perception of itching. Phototherapy has long been known and used as an effective treatment for various kinds of chronic itching. However, despite its well-known beneficial effects, the mechanisms behind the antipruritic effect of phototherapy are less well-known. In addition, phototherapy requires the use of expensive equipment in dermatology offices, patients must undergo repeated treatments and no large, randomized, controlled trials have yet supported the antipruritic effect of UV. Therefore, phototherapy is rarely recommended as a treatment method for chronic pruritic diseases or only used as a last recourse. However, the wide range of pruritic conditions that can be successfully treated with phototherapy, together with its low acute side effects, extremely low frequency of interactions with other medications, possibilities to combine phototherapy with other treatment modalities and the fact that patients of almost all ages-from childhood to old age, including women during pregnancy or lactation-can be treated make UV therapy advantageous over other treatments of chronic pruritus. Thus, despite the development of new targeted therapies against pruritus, UV therapy is neither outdated nor the 'last recourse', but should be considered early on in the treatment of chronic pruritus.

The Antipruritic Effect of Phototherapy.

Phototherapy is widely used to treat inflammatory skin diseases such as psoriasis and atopic dermatitis. Repeated suberythemogenic doses of UV-light reduce inflammation in these diseases and ultimately may lead to a complete disappearance of cutaneous symptoms for weeks or months. Chronic pruritus is an important and highly distressing symptom of many of these inflammatory skin diseases. Interestingly, pruritus is also reduced or completely abolished by UV-treatment of psoriasis and atopic dermatitis, and sometimes reduction of pruritus is the first indication for skin improvement by phototherapy. The cutaneous nervous system is an integral part of skin anatomy, and free nerve endings of sensory cutaneous nerve fibers reach up into the epidermis getting in close contact with epidermal cells and mediators from epidermal cells released into the intercellular space. Stimulation of "pruriceptors" within this group of sensory nerve fibers generates a neuronal signal eventually transmitted via the dorsal root and the spinal cord to the brain, where it is recognized as "itch". UV-light may directly affect cutaneous sensory nerve fibers or, via the release of mediators from cells within the skin, indirectly modulate their function as well as the transmission of itch to the central nervous system inducing the clinically recognized antipruritic effect of phototherapy.

Humanistic burden of chronic pruritus in patients with inflammatory dermatoses: Results of the European Academy of Dermatology and Venereology Network on Assessment of Severity and Burden of Pruritus (PruNet) cross-sectional trial.

BACKGROUND: Chronic pruritus is a multifactorial, challenging symptom of global relevance. OBJECTIVE: The European Academy of Dermatology and Venereology Network on Assessment of Severity and Burden of Pruritus (PruNet) investigation aimed to analyze the severity and humanistic burden of chronic pruritus in patients suffering from inflammatory dermatoses across Europe. METHODS: Prospectively collected routine data on 552 patients (with atopic dermatitis, contact dermatitis, prurigo nodularis, psoriasis vulgaris, lichen planus, or mycosis fungoides [pruritus numeric rating scale score ≥3]) from 9 European centers (in Austria, France, Germany, Italy, Poland, Russia, Spain, Switzerland, and Turkey) were analyzed by univariate and multivariate variance analyses of various itch characteristics and quality of life (as measured by the Dermatology Life Quality Index and the ItchyQoL). RESULTS: Duration, frequency, and intensity of pruritus (according to a numeric rating scale and visual analog scale) and related impairment of quality of life differed between European centers and dermatologic diagnoses (P < .05). The country in which the center was located had a greater impact on how patients evaluated pruritus intensity and quality of life than diagnosis did (P < .001). LIMITATIONS: One center per country was included. CONCLUSION: The humanistic burden of chronic pruritus in patients with inflammatory dermatoses is high. European cross-cultural factors may have a stronger influence than a specific dermatologic diagnosis on how patients rate intensity of pruritus and quality of life.