Isotretinoin-associated exercise-induced anaphylaxis in a patient with birch pollinosis and soybean sensitization: case presentation and literature review.

Background. Peanut and soybean allergies are listed as contraindication in the package leaflet of isotretinoin, a widely used treatment of acne vulgaris. Cross-reactivity between PR10-proteins in peanut, tree nuts, and soybean is particularly common in patients with birch pollinosis and may lead to anaphylactic reactions in sensitized patients after intake of soybean oil containing isotretinoin capsules. Case presentation. Here, we describe a young man with hazelnut and birch pollen allergy, who experienced exercise-induced anaphylaxis after isotretinoin intake on the third day of treatment. A complete allergy work-up was carried out, and sensitization to both peanut and soybean PR10-proteins was confirmed. However, oral provocation with isotretinoin remained negative in the absence of intense physical activity and longterm treatment was well tolerated. Conclusion. To our knowledge, this is the first report of an exercise-induced anaphylaxis due to isotretinoin therapy. Our literature review to assess tolerability of isotretinoin in patients allergic to peanut,...