[Sensitization to nickel sulfate in patients with ileitis terminalis (Crohn disease)].

The history of inpatients with Crohn's disease revealed several occurrences of contact dermatitis due to metal ions. Therefore, we considered the question as to whether allergic reactions to amalgam fillings or mercury, delivered in small amounts, could be a factor in the activity of regional enteritis. 23 patients with Crohn's disease (15 females, 8 males), aged from 20 to 44 years were screened by an extended standard patch test (following the rules of the ICDRG). Surprisingly, no case of hypersensitivity to amalgam and/or mercury was found. However, nickelsulfate yielded positive reactions in 39.1% of all tested patients (9/23). In comparison to the normal population this prevalence of nickelsulfate hypersensitivity is distinctly increased. It may be an epiphenomenon of Crohn's disease (sensitization via an enhanced permeability of the irritated mucous membranes for nutritive nickelsulfate) or an etiopathogenetic co-factor. In the latter case regional enteritis might be regarded as an allergic-irritative disease of the bowel.