Bullous drug eruption with Nigella sativa oil

Nigella sativa is classically used for its various therapeutic properties, particularly in the field of allergic diseases. We report a case of bullous eruption following application of Nigella sativa oil to the skin, possibly involving an associated systemic mechanism linked to ingestion of the oil. A 53-year-old woman was hospitalized for febrile rash consisting of erythematous plaques with vesicles and bullous lesions. She had Nigella sativa oil applied to her skin and ingested it for two weeks. Cutaneous histopathology revealed sub-epidermal detachment and necrosis of the epidermal surface consistent with toxic epidermal necrolysis. The lesions healed slowly, but depigmented macules persisted three months later. Patch tests for Nigella sativa oil were strongly positive. Erythema multiforme due to contact with Nigella sativa oil was initially diagnosed on the basis of lesions on skin where the oil was applied, as well as on cutaneous histopathology and positive patch tests. However, a systemic reaction such as toxic epidermal necrolysis could not be ruled out since the patient had also ingested the oil. The most likely diagnosis was thus systemic and contact bullous drug eruption. The discovery of new therapeutic properties of Nigella sativa in other clinical domains underscores the need for particular vigilance regarding future use of this substance on account of the risk of severe drug eruptions.