Systemic Contact Dermatitis Triggered by Benzalkonium Chloride in Laundry Detergent A Case Initially Misdiagnosed as Eczema.

This case shows that benzalkonium chloride is an important sensitizer for contact dermatitis.The patient did not respond to conventional eczema treatment. Pathological examination and detailed history-taking revealed that benzalkonium chloride in the detergent was the causative factor. After avoiding exposure to this allergen, the condition improved, emphasizing the need to consider contact dermatitis in patients with refractory eczema.