Fig. 2
From: Nickel-induced labial angioedema in a pediatric patient with orthodontic braces: a case report
This image depicts an orthodontic appliance damaged by corrosion, outlining various contributing factors and the nickel’s release. On the left, nickel triggers Type I hypersensitivity reactions or directly initiates mast cell degranulation. On the right, the mechanism of a Type IV allergic response is illustrated. APC: antigen-presenting cell