Two Cases of Occupational Contact Urticaria Caused by Percutaneous Sensitization to Parvalbumin

BACKGROUND: In recent years, it has been proposed that the primary mechanism for the development of food allergies is percutaneous sensitization. Since 2010, in Japan, the number of immediate-type wheat allergy due to hydrolyzed wheat protein has dramatically increased among those who have been using soap containing hydrolyzed wheat. This incidence supports the hypothesis that food allergens arise through percutaneous sensitization. CLINICAL SUMMARY: A 25-year-old man (case 1) and an 18-year-old girl (case 2) with atopic dermatitis visited our Department because of food allergy and hand eczema. After starting their work with fish, severe itchy eczema appeared on their hands. They subsequently started to experience oral allergic symptoms, intraoral itchiness and dyspnea after eating fish. Specific IgE antibodies were detected for many fishes, and skin prick tests showed positive reactions for a variety of fishes in both cases. Furthermore, the fluorescence intensities of specific IgE antibodies against parvalbumin from various types of fish in microarray immunoassay analysis showed positive reactions. We diagnosed them as contact urticaria caused by percutaneous sensitization to parvalbumin through job-related physical contact with fish. CONCLUSION: The patients' histories and findings indicate the possibility of percutaneous sensitization through occupational exposure to parvalbumin, leading to food allergy.