Delayed immediate‐type hypersensitivity to red meat and innards: current insights into a novel disease entity

Summary The development of component‐resolved diagnostics instead of whole extracts has brought about major advances in recent years. Particularly remarkable has been the identification of new disease entities based on the detection of IgE antibodies against specific individual components. In this context, delayed immediate‐type hypersensitivity to red meat and innards plays a key role. This disorder is more common in German‐speaking countries and likely still underdiagnosed. Affected individuals exhibit delayed type I reactions following the consumption of red meat or innards (responses to the latter are more rapid). All patients have IgE antibodies against the oligosaccharide galactose‐α‐1,3‐galactose – alpha‐gal. Those affected also have to avoid alpha‐gal‐containing drugs such as cetuximab or gelatin‐containing colloidal solutions. Also referred to as alpha‐gal syndrome, this condition is unique in that it is characterized by type I hypersensitivity to a sugar instead of a protein. Given that many patients have a history of recurrent episodes of acute urticaria or angioedema, dermatologists should be familiar with the alpha‐gal syndrome.