Diagnostic and treatment algorithm for chronic nodular prurigo.

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.