Mechanism: cellular hypersensitivity
Clinical features:
(1) acute onset with systemic features (fever, malaise, etc)
(2) multiple non-nodular inflammatory skin lesions (with redness, tenderness or swelling of pre-existing skin lesions or new skin lesions)
(3) acute neuritis resulting in motor and/or sensory deficits, paresthesias or nerve pain
(4) disability secondary to neurologic deficits
Triggers:
(1) leprosy chemotherapy
(2) pregnancy and partuition
(3) puberty
Treatment-related onset may start early (during the first month of therapy) or be delayed (appearing years later).
Risk factors:
(1) late adolescence or adulthood (>= 15 years in Vietnamese)
(2) borderline leprosy (BT, BB, BL), although it may occur with any type
(3) positive bacillary index
(4) widespread disease (presence of > 5 skin lesions)
