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Importance: Chronic pruritus, defined as itch experienced for 6 weeks or longer, affects approximately 22% of people in their lifetime. Approximately 1% of physician visits are for the chief concern of chronic pruritus. Chronic pruritus is associated with adverse outcomes, including impaired sleep and reduced quality of life. Observations: Chronic pruritus can be categorized by etiology into inflammatory, neuropathic, or a combination of inflammatory and neuropathic pruritus. Chronic pruritus is due to inflammation in approximately 60% of patients and may be caused by eczema, psoriasis, or seborrheic dermatitis. Chronic pruritus is due to a neuropathic or mixed etiology in approximately 25% of patients. Neuropathic causes of chronic pruritus include postherpetic neuralgia and notalgia paresthetica and are typically due to localized or generalized nerve dysregulation. Approximately 15% of people with chronic pruritus have other causes including systemic diseases with secondary itch, such as uremic pruritus and cholestatic pruritus, medication-induced pruritus such as pruritus due to immunotherapy, and infectious etiologies such as tinea corporis and scabies. When few primary changes are present, a thorough history, review of symptoms, and laboratory evaluation should be performed, particularly for people with chronic pruritus lasting less than 1 year. Clinicians should consider the following tests: complete blood cell count, complete metabolic panel, and thyroid function testing to evaluate for hematologic malignancy, liver disease, kidney disease, or thyroid disease. First-line treatment for inflammatory chronic pruritus includes topical anti-inflammatory therapies such as hydrocortisone (2.5%), triamcinolone (0.1%), or tacrolimus ointment. Approximately 10% of patients do not respond to topical therapies. In these patients, referral to dermatology and systemic oral or injectable treatments such as dupilumab or methotrexate may be considered. When no underlying systemic disease associated with pruritus is identified, patients are likely to have neuropathic chronic pruritus or mixed etiology such as chronic pruritus of unknown origin. In these patients, neuropathic topical treatments such as menthol, pramoxine, or lidocaine can be used either alone or in combination with immunomodulatory agents such as topical steroids. Other effective therapies for neuropathic pruritus include gabapentin, antidepressants such as sertraline or doxepin, or opioid receptor agonist/antagonists such as naltrexone or butorphanol. Conclusions and Relevance: Chronic pruritus can adversely affect quality of life and can be categorized into inflammatory, neuropathic, or a combined etiology. First-line therapies are topical steroids for inflammatory causes, such as hydrocortisone (2.5%) or triamcinolone (0.1%); topical neuropathic agents for neuropathic causes, such as menthol or pramoxine; and combinations of these therapies for mixed etiologies of chronic pruritus. This narrative review summarizes current evidence regarding diagnosis and treatment of chronic pruritus. [ABSTRACT FROM AUTHOR]

Introduction/Background Prurigo nodularis (PN) is a chronic inflammatory skin disease characterized by pruritic papulonodular lesions that substantially affect quality of life. Dupilumab is the first systemic treatment approved by the US Food and Drug Administration for the treatment of PN. Objectives The aim of this post hoc subgroup analysis was to assess the efficacy and safety of dupilumab in North American patients with PN. Methods LIBERTY-PN PRIME and PRIME2 were randomized, double-blind, multi-center, parallel-group, 24-week, phase 3 trials in adults with PN with ≥20 nodules and severe itch, inadequately controlled with topical prescription therapies or for whom these therapies were inadvisable. This pooled subgroup analysis of LIBERTY-PN PRIME/PRIME2 (NCT04183335/NCT04202679) included adults with moderate-to-severe PN receiving 300 mg dupilumab (n = 153) or matched placebo (n = 158) every 2 weeks for 24 weeks. Approximately 20% and 16% of enrolled patients were based in North America in the PRIME and PRIME2 trials, respectively. This analysis included the proportion of patients in the North American subpopulation who achieved (i) ≥4-point improvement in the Worst Itch Numerical Rating Scale (WI-NRS); (ii) Investigator's Global Assessment for PN stage of disease (IGA PN-S) score of 0 (no nodules) or 1 (≤5 nodules); (iii) both (i) and (ii); (iv) 9-point improvement in the Dermatology Life Quality Index (DLQI); (v) 3-point improvement in the Sleep Numerical Rating Score (NRS); (vi) 4-point improvement in Skin Pain NRS. Reported P values calculated using Chi-square or Fisher's exact tests are nominal and not adjusted for multiplicity. Treatment-emergent adverse effects (TEAE) and severe adverse effects (SAE) were assessed. Results Baseline disease characteristics of the North American subpopulation were consistent with the overall population, except for a longer duration of disease (North American subpopulation, mean [SD] years: dupilumab 7.2 [9.97] years; placebo 7.5 [9.72] years. Overall population: dupilumab 5.68 [7.21] years; placebo 5.44 [6.60] years). At Week 12, a numerically greater proportion of dupilumab-treated patients in the North American subpopulation achieved ≥4-point improvement in the WI-NRS (dupilumab vs placebo: 41.4% vs 21.9%; P = 0.1), and IGA PN-S score 0/1 (41.4% vs 28.1%; P = 0.28). By Week 24, the proportion of dupilumab-treated patients who achieved these endpoints was significantly greater than the proportion of patients who were given placebo (WI-NRS: 62.1% vs 21.9%; P = 0.0014. IGA PN-S 0/1: 55.2% vs 21.9%; P = 0.007). The proportion of patients who achieved both ≥4-point improvement in the WI-NRS and IGA PN-S score 0/1 was numerically greater at Week 12 (20.7% vs 12.5%; P = 0.5) and significantly greater at Week 24 (44.9% vs 12.5%; P = 0.009). Patients in the dupilumab group were significantly more likely to achieve a ≥9-point improvement in DLQI, vs placebo (Week 12: 65.5% vs 21.9%; P = 0.0006. Week 24: 65.5% vs 25%; P = 0.0015). Patients who received dupilumab were significantly more likely to achieve a 3-point improvement in the Sleep NRS (Week 12: 34.5% vs 9.4%; P = 0.027. Week 24: 48.3% vs 3.1%; P < 0.0001). The proportion of dupilumab-treated patients who achieved a 4-point improvement in the Skin Pain NRS was numerically greater at Week 12 (41.4% vs 18.8%; P = 0.053) and significantly greater at Week 24 (58.6% vs 21.9%; P = 0.003) compared with placebo. Incidences of TEAE and SAE in the North American subpopulation were consistent with the overall population. Conclusions Dupilumab treatment led to improvements in itch, skin lesions, and health-related quality-of-life, in North American patients with PN. Overall safety was generally consistent with the known safety profile of dupilumab. [ABSTRACT FROM AUTHOR]