What Is Prurigo Nodularis?
The exact cause of PN is unknown. Although scratching is known to cause more nodules to appear, it is unclear what causes the itching to develop in the first place. Diagnosis of the disease is based on observing signs such as extremely itchy skin with the formation of nodules. In some cases, a skin biopsy is used to confirm the diagnosis. Treatment may include corticosteroid creams, oral medications, cryotherapy, or photochemotherapy.
Source: Genetic and Rare Diseases (GARD) Information Center