A systematic review of evidence-based treatments for prurigo nodularis

Prurigo nodularis is a chronic dermatologic condition involving the development of multiple cutaneous nodules in the setting of intractable pruritus. Given emerging treatment options for this difficult-to-treat condition, a current review of therapeutics is needed. A systematic review was performed for clinical studies investigating prurigo nodularis treatment published from 1990 to present including ≥5 subjects. A total of 35 articles were assigned a level of evidence according to the Oxford Center for Evidence-based Medicine. All 5 studies investigating topical agents, including corticosteroids, calcineurin inhibitors, calcipotriol, and capsaicin, conveyed some beneficial effect with level of evidence 2b or higher. Six of 8 reports investigating photo- and photochemotherapy achieved levels of evidence 2b or greater and showed good partial response rates. Thalidomide was studied by 6 reports providing evidence of good symptom response, only 2 of which were rated level 2b or greater. Cyclosporine and methotrexate have demonstrated benefit in 4 combined studies, albeit with level 4 evidence. Pregabalin, amitriptyline, paroxetine, fluvoxamine, and neurokinin-1 receptor antagonists have demonstrated promising evidence in 5 level 2b studies. Higher-powered studies and additional randomized controlled trials are needed for the evaluation of safe and efficacious systemic treatment options for prurigo nodularis.