Brian P. Vickery, MD


Curr Opin Allergy Clin Immunol. 2012;12(3):278-282. 

In This Article

'Rush' Pilot Studies

Other investigators have also reported desensitization with more rapid updosing protocols, for example, 'rush' immunotherapy. In the first known study of rush OIT for egg allergy, Itoh et al.[21] enrolled six Japanese children aged 7–12, all of whom had grade 4 or 5 anaphylaxis to egg in the preceding year. These children were admitted to the hospital and given a baseline DBPCFC, during which the median dose eliciting symptoms was 0.152 g of egg protein. All six patients could tolerate 60 g of egg protein (approximately one whole medium egg) after an inpatient rush protocol that required a median 12 days to complete. Side effects were common, but most responded to conventional allergy therapies and no patients required epinephrine. Thereafter, patients were asked to consume at least one cooked (i.e. scrambled) egg at least twice a week. Interestingly, after 1 year, and evidently despite consuming heated egg regularly, only three of six patients (50%) passed a food challenge to 1 g of powdered egg protein, whereas the remaining three had allergic symptoms during the challenge. Compliance with the maintenance diet was not reported. In keeping with other studies, egg-specific IgE levels declined, whereas egg-specific IgG4 levels increased. At 1 year after rush OIT, there were no changes from baseline in values for skin prick tests, egg-specific basophil histamine release assays, or T cell cytokines after incubation with egg allergen.

Recently, Garcia Rodriguez et al. [22•] reported a larger uncontrolled study of rush egg OIT in 23 Spanish children aged between 5 and 17 years. In contrast to the Itoh study, this rush protocol was conducted in an outpatient research facility, enrolled patients with a milder phenotype, and utilized a 5-day protocol, although slower alternatives were permitted in patients having reactions to the rush protocol. Patients stayed in the research unit for 7h per day and underwent multiple updosings of a liquid raw egg extract, beginning with the equivalent of 0.13mg egg white powder and culminating in a 2 g equivalent of a heated egg product (i.e. an omelette). Patients did not undergo followup food challenges but were considered desensitized if they could eat a whole cooked egg and 8 ml of raw egg white extract after the rush procedure. Fourteen patients were able to complete the protocol in 5 days. When compared with the eight patients that required longer than 5 days to complete the protocol, those patients adhering to the original protocol had statistically significantly smaller egg skin test size (8.6 versus 11.2mm) and lower egg white-specific IgE levels (4.35 versus 18.6 kUA/l). One patient was withdrawn after multiple reactions during desensitization. Overall, 78% of the patients had reactions during rush OIT, most of which were mucosal or gastrointestinal; 35 reactions were judged to be mild and 20 were moderate, and no severe reactions were reported. Interestingly, seven of twenty (35%) of those patients able to complete the rush protocol within 10 days had a reaction to the omelette on the final day of the desensitization procedure. Patients completing desensitization were advised to eat one whole cooked egg per day for 3 months, and then one egg every other day for 3 additional months, and finally one egg at 72 h intervals. With a follow-up period ranging between 6 and 14 months, three patients have had three total reactions that were possibly attributable to egg exposure. Egg white-specific skin prick test wheal diameter and specific IgE levels were significantly reduced at 6 months after desensitization and IgG levels were increased. Given the high rates of allergic side effects during the rush procedures, the frequency with which treated patients had subsequent reactions, the labor-intensive nature of this approach,andthe relative ease of foodallergenavoidance (as compared with stinging insect avoidance), rushprotocols appear to offer no clear advantage over standard OIT.


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