Prurigo nodularis is a chronic skin disorder with very pruritic skin lesions which can adversely impact a patient's quality of life.
Pathogenesis: uncertain
Clinical features:
(1) multiple firm papules, plaques and nodules
(2) located on the extensor surfaces of the extremities with a symmetrical distribution
(3) flesh-colored to pink to brown or black
(4) very pruritic, either intermittently or continuously
(5) hyperkeratotic
(5) may be concurrent with another skin lesion
Concurrent conditions may include:
(1) chronic renal failure
(2) malignancy
(3) chronic liver disease
(4) HIV infection
(5) gout
(6) parasitic infection
(7) drugs
Pruritic nodules can occur in:
(1) scabies
(2) leprosy
(3) actinic prurigo
Differential diagnosis:
(1) lichen simplex chronicus
(2) hypertrophic lichen planus
(3) pemphigoid nodularis
(4) epidermolysis bullosa
(5) small fiber neuropathy
(6) foreign body reaction
