Toxic epidermal necrolysis is a severe skin disease, most often triggered as an adverse drug reaction, with high morbidity and mortality. Lamotrigine, together with other mood stabilizer drugs, constitutes the most frequent drug that causes this complication, which consists of necrosis and detachment of the epidermis and mucosa in more than 30% of the body surface, with the consequent loss of water and electrolytes, systemic inflammatory response, susceptibility to infections and even sepsis, in addition to other possible ominous sequelae. Currently, the diagnosis of bipolar disorder is made more frequently, including the age group of children and adolescents, but such a diagnostic process is characterized by difficulties and controversies to a greater extent than other psychiatric diagnoses. This requires meticulous diagnostic process and pharmacological selection, with full knowledge of the molecules in the drug arsenal so, in case of lamotrigine prescription, it should be established scrupulous psychoeducation to the patient and their family members, as well as strict and close follow-up. A propos of the case of an adolescent girl diagnosed with bipolar II disorder, who received lamotrigine during a depressive episode but with an inappropriate posology, and developed toxic epidermal necrolysis, we reviewed and commented on the corresponding literature. We conclude that extreme caution is necessary when deciding the use of lamotrigine to minimize the risk of this severe adverse effect.