Term for the allergological phenomenon of an "organ-limited" application-dependent allergy manifestation. Exemplary is the heparin allergy with allergic, dermatitic reactions at the injection sites. These patients tolerate intravenous heparin administration despite "cutaneous" sensitization. Purely theoretically, a hematogenic "contact allergic dermatitis" would be expected.
In contrast to subcutaneous injection, heparin molecules remain in the blood circulation after intravenous administration or are rapidly excreted, but do not lead to a dermatitic inflammation phenomenon at the injection sites.
This special feature of an application-dependent allergy manifestation is also observed with thiomersal (skin contact vs. intramuscular vaccination), nickel (skin contact vs. orthopaedic implants).