Lamotrigine is widely used to prevent bipolar depression. Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) is a rare, potentially life-threatening adverse effect. The long latency between drug exposure and disease onset, added to the high variability of its clinical presentation, can increase the risk of misdiagnosis lamotrigine withdrawal delay.

To highlight potential risk factors that can be related to a worse clinical onset and evolution of lamotrigine-induced DRESS syndrome.

We report the case of a 25-year-old-man, with a type I bipolar disorder, treated with lithium and lamotrigine 50mg per day during the first 13 days of treatment, progressively increase up to 200mg. Thirty-five days after the treatment initiation, a pruritic rash appeared in his upper arms, and scabies infestation was diagnosed. After 72hours, the patient required urgent hospitalization due to hemodynamic instability.

On admission, facial edema and erythrodermia were involving 70 to 80% of the body surface. DRESS diagnosis due to lamotrigine was made following RegiSCAR criteria (Table 1). Psychiatric medication was stopped and DRESS treatment established. Complete recovery without recurrence was achieved after 2 months.

The lamotrigine up titration faster than recommended may have facilitated the DRESS syndrome reaction. Moreover, the latency between lamotrigine introduction and the rash onset could have increased the possibilities of misdiagnosis. In light of this, physicians need to consider at least the last 3 months treatment history when assessing a rash, as the delay of DRESS syndrome diagnosis can fastly lead to a fatal event.

Table not available.