BACKGROUND: 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.
OBJECTIVE: To provide practical guidance to help United States dermatologists diagnose and effectively treat patients with PN.
METHODS: We participated in a roundtable discussion to develop consensus recommendations on diagnosis and treatment of PN from a United States perspective.
RESULTS: 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.
CONCLUSIONS: Data on PN are from anecdotal or small clinical trials, and all treatments are currently used off-label.
CONCLUSIONS: An effective treatment approach for patients with PN should be based on clinical judgment and tailored to the individual needs of the patient.

Chronic nodular prurigo (CNPG) is a subtype of chronic prurigo, also called prurigo nodularis, and a chronic skin condition characterized by intensely pruritic nodular lesions. Although the exact cause of CNPG is unknown, it appears to result from a repetitive itch-scratch cycle induced by neuronal sensitization to chronic pruritus. CNPG is associated with an underlying dermatologic condition in about half of patients, and it can also be attributed to systemic, neurologic, psychogenic, or unknown causes. For most patients, multiple underlying causes are identified. Patients with CNPG often experience impaired quality of life, sleep disturbance, anxiety, and depression. To encourage consistent and accurate diagnosis and treatment of CNPG across regions, we are proposing a diagnostic and treatment algorithm that includes initial assessment of core symptoms, detailed dermatologic history and clinical examination, patient-reported outcomes, diagnostic workup, and recommended therapies. This information is supplemented with photographs to illustrate clinical appearance and disease severity. Because CNPG is often multifactorial and it can take months to years for lesions to heal, interdisciplinary cooperation and long-term management are important.

Introduction: Pruritus is a common symptom associated with several potential underlying causes, including both dermatologic and systemic diseases; it can also occur without an identifiable cause. Current treatment options are limited and most patients experience impaired quality of life. Serlopitant is a neurokinin 1 (NK1) receptor antagonist under development for the treatment of pruritus associated with various dermatologic conditions and chronic pruritus of unknown origin. Areas covered: This review describes the epidemiology and unmet needs of patients with chronic pruritus, focusing specifically on patients with prurigo nodularis, psoriatic itch, and chronic pruritus of unknown origin; the rationale for targeting the NK1 receptor for treatment of chronic pruritus; and the clinical development of serlopitant, including efficacy and safety data from completed phase II studies. Expert opinion: There is an unmet need for novel, safe, and effective therapies to treat chronic pruritus. Serlopitant has shown promising efficacy, safety, and tolerability across different patient populations, including adolescents and elderly patients. In contrast to less convenient administration options, serlopitant is a once-daily oral tablet, which is expected to facilitate compliance.

The aim of this multicentre, randomized, double-blind, placebo-controlled, cross-over, phase-II study was to determine the antipruritic effect of aprepitant vs. placebo in 58 patients with anti-histamine-refractory chronic pruritus in chronic nodular prurigo. Patients were randomized to receive either first oral aprepitant 80 mg/day or placebo for 4 weeks. Following a 2-week wash-out phase, the patients were crossed-over to receive the other treatment for 4 weeks. Primary efficacy criterion was the intra-individual difference between mean itch intensity (visual analogue scale) at baseline compared with the end of treatment period. Prurigo lesions, pruritus course, quality of life, patient benefits, and safety were secondary parameters. No significant differences were found between aprepitant treatment and placebo for any of the parameters investigated. Under the experimental conditions of the study, aprepitant, 80 mg daily for 4 weeks, did not have an antipruritic effect in patients with chronic prurigo. (DRKS00005594; EudraCT Number: 2013-001601-85).