Introduction: Lamotrigine is an anti-epileptic drug indicated for the treatment of bipolar disorder and recurrent depressive disorders. Its efficacy has been demonstrated. However, its use may be limited by the risk of severe, life-threatening allergic reactions. Objectives And Methods: We report hereafter the clinical case of a patient suffering from bipolar depression treated with lamotrigine which induced skin allergies in her. Our objective will be to detail the rules of prescribing the treatment, to describe Steven Johnson syndrome, a serious adverse effect to lamotrigine, to discuss the urgent course of action in the event of severe allergic reactions to lamotrigine as well as the therapeutic options after a hypersensitivity reaction to lamotrigine. Clinical Vignette:This is a patient followed in psychiatry for bipolar disorder, put on esitalopram clomipramine, aripiprazole and Lamotrigine, who was admitted to dermatology for minimal erythematous maculo-papular rash on the face and limbs with involvement of the oral and genital mucosa appeared 4 weeks after introduction of lamotrigine. Conclusion: Despite the efficacy of lamotrigine as an effective mood regulator in the treatment of recurrent depressive episodes and depressive episodes in bipolar disorder, this antiepileptic drug must be used with caution to avoid serious life-threatening reactions.