Egg allergy accounts for one of the most prevalent food hypersensitivities in industrialized countries. The majority of the relevant egg allergens have been identified in the egg white: ovomucoid (Gal d 1), a Kazal-type serine protease inhibitor; ovoalbumin (Gal d 2), a serine protease inhibitor; ovotransferrin (Gal d 3); and the egg lysozyme (Gal d 4). Ovomucoid consists of three tandem domains, each homologous to pancreatic secretory trypsin inhibitor (Kazal) and each with an actual or putative reactive site for inhibition of serine proteinases.