Episodic edema in type 2 lepra reaction can be caused by transient lymphatic obstruction in the lymph node.

Fourteen patients with lepromatous leprosy developed attacks of edema of the hands and/or feet associated with attacks of type 2 lepra reaction (erythema nodosum leprosum). The regional lymph nodes were enlarged and often tender when edema was present. Lymph node biopsies in five cases showed compression of the subcapsular sinus against the thickened fibrotic capsule of the inflamed node. It is suggested that this obstructs the inflow of lymph into the regional nodes, thereby causing the edema.