Plasma cell vulvitis: a rare cause of intractable vulvar pruritus.

Comment. The association between TEN and the use of lamotrigine in patients has been previously reported with concomitant use of valproic acid and lamotrigine. It has been hypothesized that valproic acid may interfere with the metabolism of lamotrigine, leading to increased lamotrigine blood levels. Our patient acquired TEN as a result of lamotrigine being concomitantly used with carbamazepine. Carbamazepine is one of the drugs most frequently implicated in TEN. It decreases lamotrigine blood levels by increasing its clearance. Also, the patient reported prior use of carbamazepine for the previous 3 years with no skin rash, so lamotrigine appears to be the causative agent. However, because of the temporal relationship of the onset of the patient’s rash and use of 2 antiepileptic drugs that are known to cause severe rashes, it is not certain which drug was the definite culprit. Further epidemiologic studies are needed to identify the incidence of lamotrigine-induced severe cutaneous reactions and the relative risk in concomitant use with other antiepileptic drugs.