Carbamazepine induced erythroderma with systemic lymphadenopathy.

We describe a 13-year-old girl with carbamazepine (CBZ)-induced erythroderma associated with marked generalized lymphadenopathy, a very rare form of CBZ hypersensitivity. The results of lymphocyte stimulation test (LST) and patch testing provided valuable evidence for distinguishing CBZ hypersensitivity from immunoblastic lymphadenopathy (IBL) and infectious mononucleosis (IM). An increased LST value was the only clue leading us to suspect a hypersensitivity reaction against CBZ at a peak stage of the skin eruption. In contrast, CBZ patch testing, which was negative at that time, became positive when the erythroderma regressed after discontinuation of CBZ. These findings suggest that LST can be a useful tool in diagnosing similar cases of hypersensitivity reactions to CBZ and other drugs, especially when patch test results are negative.