The sting challenge test in Hymenoptera venom allergy: pros and cons.

This paper examines the main features of the deliberate sting challenge with regard to the type of insect, the advantages and disadvantages of its use in untreated and treated patients and after discontinuation of specific immunotherapy.

Asthma after consumption of snails in house-dust-mite-allergic patients: a case of IgE cross-reactivity.

A group of 28 patients from Italy was studied who had asthma after consumption of snail. All patients also had asthma and/or rhinitis caused by house-dust mite. RAST analyses confirmed the combined sensitization to snail and mite. In a few sera, IgE antibodies reactive with other foods of invertebrate origin (mussel and shrimp) were detected. RAST inhibition showed that most IgE antibodies against snail were cross-reactive with house-dust mite. In contrast, the mite RAST was not significantly inhibited by snail. This indicates that house-dust mite was the sensitizing agent. Immunoblot analyses revealed multiple bands in snail extract recognized by IgE. In contrast to what has been described for cross-reactivity between shrimp and mite, tropomyosin played only a minor role as a cross-reactive allergen in these patients. The observations in this study indicate that snail consumption can cause severe asthmatic symptoms in house-dust-mite-allergic patients. It might, therefore, be advisable to screen mite-allergic asthma patients for allergy to snail and other invertebrate animal foods.

Possible induction of food allergy during mite immunotherapy.

Sera of 17 patients receiving immunotherapy for house-dust mite allergy were tested for IgE antibodies against snail and shrimp. Serum samples were taken at the start of immunotherapy and 14-20 months later. While the average IgE response to mite, Der p 1, and Der p 2 did not alter significantly, the average response to snail showed a significant increase. This included two conversions from negative to strongly positive. These novel IgE antibodies against snail were shown to be cross-reactive with mite. Three patients had a positive RAST for shrimp. For one of them, a strong increase of IgE against shrimp (and snail) was observed. In 2/3 snail/shrimp-positive sera, IgE antibodies against the cross-reactive allergen tropomyosin from mite, snail, and shrimp were demonstrated. A clear IgE response to snail (> 10% binding in a snail RAST) was confirmed by a positive skin prick test (SPT) for 6/10 patients. The two patients with antitropomyosin IgE also had a positive SPT for shrimp, and demonstrated the oral allergy syndrome (OAS) after eating shrimp. The observations in this study indicate that house-dust mite immunotherapy is accompanied by the induction of IgE against foods, including tropomyosin-reactive IgE. Food allergy (OAS) was observed in patients that had IgE antibodies against this cross-reactive allergen. In conclusion, induction of IgE during mite immunotherapy might occasionally cause allergy to foods of invertebrate animal origin.

Shortness of interval between two stings as risk factor for developing Hymenoptera venom allergy.

The aim of the study was to determine whether a short interval (< 2 months) between two consecutive stings influences the development of Hymenoptera venom allergy. The study compared the sting-interval distribution in 120 allergic patients who experienced a first-time systemic reaction to a Hymenoptera sting, and in 100 healthy controls. A significant difference in sting-interval distribution between the two groups was found (P = 0.0001). In 71 of 120 allergic patients, the sting that provoked the systemic reaction had been preceded by another, completely tolerated sting not more than 2 months before. However, in the control group only four subjects out of 100 had received two consecutive stings within less than 2 months. In conclusion, a short interval between two consecutive stings seems to be a risk factor for the onset of Hymenoptera venom allergy.

Early decrease in skin reactivity after rush venom immunotherapy.

Previous studies have documented changes in skin reactivity after specific immunotherapy. The aim of this study was to evaluate the time course of this phenomenon after rush venom immunotherapy. According to the method of endpoint evaluation, the skin reactivity of 38 patients allergic to venom was studied 24 h before and after the end of a rush venom immunotherapy protocol (7 days). The results were compared with 13 controls. An early significant decrease in skin reactivity was documented (p < 0.001), which was not related to an increase in specific IgG. Thus, rush venom immunotherapy induces a very early decrease in skin reactivity.