[Two infants with classical polyarteritis nodosa but not Kawasaki disease]

We experienced two infants with polyarteritis nodosa (PN). The symptoms started with high fever and skin rash, which were similar to those of Kawasaki disease (KD). However, the involvement of central nervous system and lung, such as distension of large fontanel, stridor and mild disturbance of consciousness, occurred and the systemic vasculitis resulted in hypoalbuminemia and severe generalized edema. They flared up twice or three times during the long clinical courses. Finally, both had multiple giant coronary aneurysms and lung fibrosis. The clinical courses of these patients were different from those of KD in that: (1) the severity of vasculitis, (2) the wide-spread nature of the vasculitis, and (3) the chronic and recurrent clinical course. It is very difficult to distinguish PN from severe KD in the early stage of the diseases especially in infancy. But in the cases intractable to high-dose gamma-globulin therapy and plasma exchange, it is needed to suspect PN and to induce more aggressive immunosuppressive therapy, such as methylprednisolone pulses and cyclophosphamide pulse therapy as soon as possible.