Anaphylaxis due to potato starch (possibly caused by percutaneous sensitization).

An 8-year-old boy with poor control of atopic dermatitis could eat potato products such as French fries without restrictions until 21 months of age. However, he developed generalized urticaria after eating potato products at the same age. Therefore, potatoes were excluded from his diet; nevertheless, he continued to consume a very small amount of potato starch but was without symptoms until the age of 8 years. At this age, he developed anaphylaxis after consuming potato starch and required administration of intramuscular epinephrine. He tested positive for potato-specific immunoglobulin E, skin prick test, and basophil activation test. He developed severe eczema with dry skin and erosion. We later discovered that potato starch had been used for play clay at his nursery school. Although he discontinued using potato starch play clay, it remained present in his surroundings for 6 years. His potato allergy may have developed and continued to worsen as a result of making indirect contact with surfaces that had previously been exposed to the allergen. Two-dimensional Western blot analysis on potato starch revealed the presence of proteins binding to the immunoglobulin E of the patient. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis findings showed that 5 of the 6 protein bands had a similar molecular weight as that of potato proteins. Thus far, there are no reports of anaphylaxis due to potato starch. Children with atopic dermatitis or damaged skin may have sensitivity to potato starch and could develop anaphylaxis as noted in this case.