Lamotrigine associated extensive hyperpigmentation: A case report and literature review

Rationale: Lamotrigine (LTG)-associated extensive hyperpigmentation is rare and may persist for a long time or even become permanent. LTG-associated cutaneous adverse reaction (CAR) manifests initially as mild maculopapular exanthema (MPE). The first step in CAR therapy is to immediately discontinue the offending LTG for predicting evolution to mild or severe forms not always possible. Here, we present a rare case of LTG-associated extensive hyperpigmentation for delaying the withdrawal of LTG. Patient concerns: We describe the case of a female adolescent with a history of depression managed with LTG, who developed a mild MPE. Unfortunately, the patient did not discharge LTG after the occurrence of MPE until 20 days later. Then she developed a residual extensive hyperpigmentation in her trunk and extremities. Diagnoses: After a series of physical examinations and retracing past medical history, she was diagnosed with LTG-associated extensive hyperpigmentation. Interventions: The patient refused any treatment. Outcomes: Nine months later, there still existed residual hyperpigmentation in her trunk and extremities, and the range and color of hyperpigmentation have not changed significantly. Lessons: This case suggests that LTG may cause not only MPE but also extensive hyperpigmentation. When a patient displays a mild MPE following the initiation of LTG in the outpatient clinic, LTG-associated CAR should not be overlooked as a diagnosis, and early withdrawal of LTG should be considered at first.