[TWO CASES OF ADULT EGG ALLERGY THAT DEVELOPED AFTER USING COSMETIC PRODUCTS CONTAINING OSTRICH EGG YOLK EXTRACT]

Ostrich antibodies have a cost advantage over antibodies derived from small animals and are commercially used in diagnostic reagents. They are also expected to be effective in preventing infection, and products containing them, such as cosmetics, are available on the market. We encountered two cases of egg allergy in adult women after using cosmetics containing ostrich egg yolk extract to which this antibody was applied. Case 1: a 44-year-old woman who consumed Japanese pizza with semi-cooked eggs and experienced eyelid swelling, abdominal pain, vomiting, urticaria, and dyspnea. Case 2: a 21-year-old woman who ate "oyakodon" (a chicken and egg dish) containing raw egg yolk, resulting in a cough, hoarseness, itching and hypotension. They had used cosmetics containing ostrich egg yolk extract for approximately five years and one year, respectively. Both patients had elevated egg yolk-specific IgE antibody titers, consistent with bird-egg syndrome, but neither had a history of bird breeding. In both cases, the results of prick tests for chicken egg white, egg yolk and the cosmetics they used were positive, and the basophil activation tests of the same cosmetic products were also positive. From these results, we speculated that the use of cosmetics containing ostrich egg yolk extract is possibly associated with their development of an egg allergy.