Prurigo nodularis (PN) is a chronic skin disorder characterized by multiple, firm, pruritic nodules typically localized to the extensor surface of the extremities (picture 1A-B). PN is frequently associated with a history of atopic dermatitis or chronic pruritus [1,2].
Prurigo nodularis will be discussed in this topic. Other skin conditions associated with chronic pruritus, including atopic dermatitis, nodular scabies, lichen planus, and bullous pemphigoid, are discussed separately.
The incidence and prevalence of prurigo nodularis (PN) are not known. PN can occur in all age groups but primarily affects older adults. In a review of 108 cases of PN, the median age was 62 years . Both sexes are equally affected.
In approximately half of cases, PN is associated with a history of atopic dermatitis . Patients with atopic dermatitis may have PN at an earlier age than nonatopic patients . Prurigo nodularis occurs in approximately 5 percent of patients with HIV infection, particularly among individuals with a CD4+ count <200 cells/mm3 . In tropical areas, PN may be the first manifestation of HIV infection .