Mechanism: circulating immune complexes
Clinical features of a Type 2 reaction (ENL):
(1) presence of tender skin nodules
(2) systemic symptoms, including fever, anorexia and malaise
(3) variable arthralgias, bone tenderness, dactylitis, neuritis, edema, orchitis and lymphadenopathy
A patient with neuritis may develop neurologic deficits which can result in significant disability.
ENL may occur:
(1) as a single acute episode
(2) as multiple acute episodes
(3) as a chronic condition
Triggers:
(1) leprosy chemotherapy
(2) vaccination or other immune system stimulation
Risk factors for a Type 2 reaction:
(1) LL or BL leprosy with disseminated lesions
(2) bacillary index > 3
(3) female gender
