Mediators of Chronic Pruritus in Atopic Dermatitis: Getting the Itch Out?

For centuries, itch was categorized as a submodality of pain. Recent research over the last decade has led to the realization that itch is in fact a separate and distinct, albeit closely related, sensation. Chronic itch is a common complaint and has numerous etiologies. Various receptors (TRPA1, TRPV1, PAR2, gastrin-releasing peptide receptor (GRPR), Mas-related G proteins), secreted molecules (histamine, nerve growth factor (NGF), substance P (SP), proteases), and cytokines/chemokines (thymic stromal lymphopoietin (TSLP), IL-2, IL-4, IL-13, and IL-31) are implicated as mediators of chronic pruritus. While much remains unknown regarding the mechanisms of chronic itch, this much is certain: there is no singular cause of itch. Rather, itch is caused by a complex interface between skin, keratinocytes, cutaneous nerve fibers, pruritogenic molecules, and the peripheral and central nervous systems. Atopic dermatitis is one of the most itchy skin dermatoses and affects millions worldwide. The sensation of atopic itch is mediated by the interplay between epidermal barrier dysfunction, upregulated immune cascades, and the activation of structures in the central nervous system. Clinicians are in possession of an arsenal of different treatment options ranging from moisturizers, topical immunomodulators, topical anesthetic ion channel inhibitors, systemic immunomodulators, as well as oral drugs capable of reducing neural hypersensitization. Emerging targeted therapies on the horizon, such as dupilumab, promise to usher in a new era of highly specific and efficacious treatments. Alternative medicine, stress reduction techniques, and patient education are also important treatment modalities. This review will focus on the mediators of chronic pruritus mainly associated with atopic dermatitis (atopic itch), as well as numerous different therapeutic options

Psychological Interventions in the Treatment of Chronic Itch

Patients with chronic itch suffer from higher levels of depression and anxiety than their healthy counterparts. Furthermore, psychological factors, such as stress, are known to aggravate itch. The mere act of thinking about itching can induce the sensation. Interventions like habit reversal training and arousal reduction have been shown to have positive effects on itch relief. Yet, there is still limited data on the psychological management to control the itch scratch cycle and a description of methods suitable to address itch. In this review, we describe different psychological interventions shown to be effective in the treatment of chronic itch. We also provide suggestions based on our experience of suitable interventions for patients with different types of itch

Practical approaches for diagnosis and management of prurigo nodularis: United States expert panel consensus

Prurigo nodularis (PN) is a chronic disease characterized by intensely pruritic, raised, nodular lesions. Because there are currently no United States Food and Drug Administration-approved therapies specifically for PN, management is highly variable, and no consensus exists on treatment regimens. To provide practical guidance to help United States dermatologists diagnose and effectively treat patients with PN. We participated in a roundtable discussion to develop consensus recommendations on diagnosis and treatment of PN from a United States perspective. The core findings in PN are the presence of firm, nodular lesions; pruritus lasting at least 6 weeks; and a history or signs, or both, of repeated scratching, picking, or rubbing. The diagnostic workup involves a complete review of systems, considering potential systemic diseases, and assessment of disease severity, including disease burden and pruritus intensity. Treatment should be selected based on a patient's clinical presentation, comorbidities, and response to prior treatments and should address both neural and immunologic components of pruritus. Data on PN are from anecdotal or small clinical trials, and all treatments are currently used off-label. An effective treatment approach for patients with PN should be based on clinical judgment and tailored to the individual needs of the patient

Eosinophilic dermatosis of hematologic malignancy responding to dupilumab in a patient with chronic lymphocytic leukemia.

Leukemia cutis (LC) and eosinophilic dermatosis of hematologic malignancy (EDHM) are rare cutaneous manifestations of hematologic malignancies. Various therapeutic options have been reported, with largely underwhelming responses. We present a patient with chronic lymphocytic leukemia (CLL) with concomitant LC and EDHM who was treated with dupilumab

510 - Dupilumab is efficacious in patients with prurigo nodularis regardless of stable use of topical corticosteroids and topical calcineurin inhibitors: pooled results from two phase 3 trials (LIBERTY-PN PRIME and PRIME2)

Abstract Introduction Prurigo nodularis (PN) is a chronic inflammatory skin condition characterized by severely itchy skin nodules, which substantially affects quality of life. Although topical treatments are frequently prescribed, these therapies are limited by insufficient demonstrated evidence for efficacy, and/or associated side effects. Objectives This study reports the effect of dupilumab on pruritus, skin lesions, and quality of life in patients with PN, with or without stable use of topical corticosteroids (TCS) and/or topical calcineurin inhibitors (TCI), in an analysis of pooled data from two phase 3 trials. Materials & Methods LIBERTY-PN PRIME (NCT04183335) and PRIME2 (NCT04202679) were two randomized, double-blind, placebo-controlled, 24-week studies. Adults with PN inadequately controlled by topical prescription therapies, or for whom those therapies are inadvisable, were randomized 1:1 to dupilumab 300 mg every 2 weeks or matched placebo. “Stable use” was defined as maintaining the same medicine (low-to-medium potency TCS and/or TCI) during the study, with the same frequency of treatment (once or twice daily) as from 2 weeks prior to screening. Efficacy was assessed from baseline to Week 24 through the Worst Itch Numerical Rating Scale (WI-NRS; scored 0–10; high scores represent a poorer outcome), and the Investigator’s Global Assessment for PN-Stage score (IGA PN-S; scored 0–4; high scores represent a poorer outcome). Impact on Health-Related Quality of Life (HRQoL) was assessed through the Dermatology Life Quality Index questionnaire (DLQI; 10 questions scored 0–3 with a maximum score of 30; high scores represent poorer HRQoL). Results 311 patients were randomized (dupilumab/placebo n = 153/158), including 182 patients with stable use of TCI/TCS (dupilumab/placebo N = 91/91) and 129 patients without (dupilumab/placebo N = 62/67). Baseline demographics and disease characteristics were well balanced in both subgroups. At Week 24, significantly more patients treated with dupilumab with or without stable use of TCI/TCS achieved a ≥ 4-point improvement in WI-NRS (59.3%/58.1%) vs placebo (13.2%/26.9% [nominal P < 0.0001/P < 0.0001]). The proportion of patients achieving an IGA PN-S score of 0 or 1 at Week 24 was also significantly higher in the dupilumab group for patients with or without stable use of TCI/TCS (48.4%/43.5%), vs placebo (11.0%/25.4% [nominal P < 0.0001/P = 0.0319]). The positive impact of dupilumab treatment on HRQoL was greater, for patients with and without a stable use of TCI/TCS vs placebo, as suggested by the mean change from baseline in DLQI at Week 24 (−12.9/−11.9 vs −5.5/−7.1 [nominal P < 0.0001/P < 0.0001], respectively). Although the placebo response was higher for patients without stable use of TCI/TCS, the effect of dupilumab treatment was comparable in the two subgroups. Treatment-emergent adverse events (TEAEs) occurred with similar rates in dupilumab-treated patients with or without stable use of TCI/TCS (59.3%/60.7%), compared with placebo (53.3%/47.8%). Patients with or without stable use of TCI/TCS had similar rates of severe TEAEs in the dupilumab groups (2.2%/4.9%) and placebo groups (3.3%/4.5%). Conclusion Dupilumab treatment improves itch, skin lesions, and quality of life in patients with PN, with an acceptable safety profile, with little to no influence from concomitant treatment with topical therapies (TCI/TCS)

Is orofacial granulomatosis a distinct clinical disorder?

Orofacial granulomatosis is a rare disorder that is heterogeneously defined in the published literature. Herein, we describe a patient with orofacial granulomatosis with clinical and histologic evidence, discuss differential diagnoses, and offer clinical pearls for diagnosing and assessing this disorder. Our case provides support that orofacial granulomatosis is a distinct disorder as opposed to a sequela of other systemic granulomatous diseases. This information will aid dermatologists in decision making and diagnosing the disorder

The Genetics of Chronic Itch: Gene Expression in the Skin of Patients with Atopic Dermatitis and Psoriasis with Severe Itch

To identify itch-related mediators and receptors that are differentially expressed in pruritic skin, we used RNA sequencing to analyze the complete transcriptome in skin from paired itchy, lesional and nonitchy, nonlesional skin biopsies from 25 patients with atopic dermatitis and 25 patients with psoriasis and site-matched biopsies from 30 healthy controls. This analysis identified 18,000 differentially expressed genes common between itchy atopic and psoriatic skin compared with healthy skin. Of those, almost 2,000 genes were differentially expressed between itchy and nonitchy skin in atopic and psoriatic subjects. Overexpression of several genes, such as phospholipase A2 IVD, substance P, voltage-gated sodium channel 1.7, and transient receptor potential (TRP) vanilloid 1, in itchy skin was positively correlated with itch intensity ratings in both atopic dermatitis and psoriasis. Cytokines such as IL-17A, IL-23A, and IL-31 had elevated gene transcript levels in both itchy atopic and psoriatic skin. However, expression of genes for TRP vanilloid 2, TRP ankyrin 1, protease-activated receptor 2, protease-activated receptor 4, and IL-10 was found to be increased only in pruritic atopic skin, whereas expression of genes for TRP melastatin 8, TRP vanilloid 3, phospholipase C, and IL-36α/γ was elevated only in pruritic psoriatic skin. This “itchscriptome” analysis will lead to an increased understanding of the molecular mechanisms of chronic pruritus and provide targets for itch treatment irrespective of disease state