Epidemiology of Prurigo Nodularis compared with Psoriasis in Germany: A Claims Database Analysis

Prurigo nodularis is an itchy skin disease with unknown epidemiology. This study aimed to describe the epidemiology of prurigo nodularis compared with that of psoriasis. The German sickness fund claims database, with 2,783,175 continuously insured patients, included 1,720 patients diagnosed with prurigo nodularis and 51,390 with psoriasis. Patients with prurigo nodularis were averagely 8 years older than psoriasis patients and more often were women (p < 0.001). Annual incidence was a constant 0.02% in prurigo nodularis, and decreased steadily from 0.53 to 0.42% in psoriasis; cumulative incidence was 0.1% for prurigo nodularis and 1.9% for psoriasis. Prevalence was 0.1% for prurigo nodularis and 4.7% for psoriasis, with a one-year mortality of 5.4% for prurigo nodularis and 1.2% for psoriasis (p < 0.001). The most frequent pre-existing comorbidities in patients with prurigo nodularis were inflammatory dermatoses and depression. This epidemiological study found a low prevalence of prurigo nodularis, manifesting different demographics and comorbidities compared with psoriasis.