Micol: The Chameleon FPIES
Since her birth, Micol had taken CM four-times. The first time, when she was ten days old, she vomited twice. Then, three times within the third and fourth months of life, 3 h after the ingestion of 30 ml of formulated milk, the baby started to vomit repetitively and presented with pallor, lethargy and diarrhea. 6−8 h after the symptoms started, Micol was fine. SPTs performed with casein, β-lactoglobulin and lactalbumin were negative, while fresh CM SPT was weakly positive (mean wheal diameter: 4 mm). We diagnosed atypical FPIES and from the age of 8 months, Micol consumed an extensively hydrolyzed formula of casein instead of CM as breast milk was terminated. At the age of 16 months, a year after the last adverse episode, Micol performed and passed an OFC, ingesting 200 ml of CM without showing any symptoms, so we suggested to reintroduce CM into the child's diet. However, after 5 days of ingestion of CM without any other problems except a slight erythema in the perioral region, Micol presented with cough and vomiting 20 min after drinking 200 ml of CM. On the 7th day, 40 min after she finished her CM meal, the child presented with vomiting without coughing, and hives and rash appeared on the anterior surface of the body, which was the skin area that came in contact with vomit. Eating parmesan did not, however, cause symptoms. So, eight days after the first OFC, a second one was performed; SPTs were positive for fresh CM (mean wheal diameter: 5 mm), β-lactoglobulin (mean wheal diameter: 3 mm) e lactalbumin (mean wheal diameter: 4 mm), while the one with casein was negative. Micol consumed 220 ml of CM in one dose; some hives showed on the perioral area where some drops of milk dripped. 20 min after the child finished the CM meal, she presented with cough and vomiting; hives and erythema appeared also on the body surfaces that came in contact with vomit. In conclusion, in Micol's case, we observed a shift from FPIES to an IgE-mediated generalized reaction, where, however, the involvement of the GI tract remains important. This means that Micol was cured of FPIES – that is, she no longer presented symptoms compatible with FPIES when she ate CM again. Only a few days later the symptoms of IgE-mediated allergy appeared. And before 16 months of age, symptoms compatible with an IgE-mediated form had never presented. The two clinical expressions have never been contemporaneous. Similar stories were also reported by Katz et al. and Kessel et al. Micol's story can support, according to us, the hypothesis that there are different phenotypes of FPIES; in some cases the role of specific IgE becomes more important. But we want to emphasize once again that there is controversy surrounding this idea and mention that some researchers may not agree with this concept.
Expert Rev Clin Immunol. 2013;9(8):707-715. © 2013 Expert Reviews Ltd.