Feinglos M N, Jegasothy B V
Lancet. 1979 Jan 20;1(8108):122-4. doi: 10.1016/s0140-6736(79)90517-8.
An investigation of two unrelated patients who had local cutaneous hypersensitivity reactions after injection of any commercially available insulin preparation has shown that the cause of the allergy was zinc. Zinc-insulin and zinc sulphate induced transformation and proliferation of peripheral-blood lymphocytes from these patients; they also induced the production of a specific leucocyte inhibitory factor. Intradermal skin-tests for zinc were positive in both patients. Similar studies carried out in a patient whose cutaneous allergy to insulin was corrected by changing from mixed beef-pork to pure pork insulin were negative. Zinc-free insulin did not produce any allergy in the first patients. The number of patients in whom zinc (which is present in all commercially available insulin preparations) is a cause of "insulin" allergy is unknown. These patients may by identified by intradermal skin-tests. This previously unrecognised allergy should be considered in all patients whose insulin allergy does not respond to conventional therapy.
