Allergic and nonallergic rhinitis and skin sensitization to metals: is there a link?

Chromium, Cobalt and Nickel are responsible for contact dermatitis, that is largely prevalent in the general population. They can act also as irritants in the upper and lower respiratory airways. Also rhinitis (allergic and nonallergic) is a high prevalence disorder. Both diseases could share some common inflammatory mechanisms, but the clinical association between skin sensitization to metals and rhinitis was never studied. We assessed the presence of skin sensitization to metals in subjects with rhinitis. Patients suffering from rhinitis underwent a standard diagnostic procedure, including skin testing, nasal endoscopy and nasal cytology. Control healthy subjects were also included. None of the patients had skin diseases. All subjects underwent patch test with Chromium, Cobalt and Nickel. None of the 26 controls had positive skin prick test or nasal cytology. The 82 rhinitis patients were subdivided into allergic (group A = 27), nonallergic (group B = 31) and overlapping (group C = 24). The prevalence of positive patch test to metals was 26% in group A, 45% in group B, 42% in group C and 31% in controls. The percentage of patch-positive subjects was significantly different between Group A and B (p = 0.0045; OR: 0.43), Group A and C (p = 0.0186; OR: 0.49), and Group B and controls (p = 0.0360; OR: 1.85). There was a significant difference between groups A + controls and B + C. Even in the absence of skin diseases, the prevalence of sensitization to metals (patch test) is greater in nonallergic and overlapping rhinitis, as compared to allergic rhinitis and controls.