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BackgroundThe aetiology of anaphylaxis differs according to types of foods consumed, fauna and foliage and cultural practices. Although the aetiology of anaphylaxis in Western countries are well known, the causes in South Asian countries have not been reported. We sought to determine the causes of anaphylaxis in patients referred to an immunology clinic in Colombo, Sri Lanka.Methods238 episodes of anaphylaxis were reviewed in 188 patients who were referred and skin prick tests and in vitro tests (ImmunoCap) were carried out to assess the presence of allergen specific IgE. Clinical features and severity of anaphylaxis was also recorded along with treatment received.ResultsAnaphylaxis to food either following direct exposure 90/238 (37.5%) or after exercise in the form of food dependent exercise induced anaphylaxis 29/238 (12.2%) was the predominant cause of anaphylaxis. Allergy to cow’s milk and red meat, after immediate exposure, accounted for 66/238 (27.7%) of instances of all episodes of anaphylaxis and 66/90 (73.33%) of anaphylaxis due to food. Vaccines accounted for 28/238 (11.8%) of instances of anaphylaxis, especially among children. Of those who developed anaphylaxis to the MMR (n = 14), 71.4% of them had specific IgE to cow’s milk and 35.7% of them had specific IgE to beef. Of those who developed anaphylaxis to insect stings, 27/42 of these episodes occurred following stings of ants (family Formicidae). The predominant cause of anaphylaxis changed with the age, with food allergy being the most frequent trigger of anaphylaxis in childhood, while drug allergy and idiopathic anaphylaxis being more frequent after 30 years of age.ConclusionsIn this cohort, anaphylaxis to red meat appears to be the predominant cause of food induced anaphylaxis and presence of beef specific IgE and cow’s milk, appears to be a predisposing factor for vaccine induced anaphylaxis.

BackgroundAllergy to Vespa affinis venom is common in the Asia Pacific region. Venom preparations for diagnosis are not commercially available for this species.MethodsThe prominent allergens in V. affinis venom were identifiedusing immunochemical methods. Use of ImmunoCAP of Vespula vulgaris crude venom/its components and a passive basophil activation test (BAT) in the diagnosis of patients who had anaphylaxis to V. affinis venom (n = 30) were also accessed. The IgE double-positivity rates (positive to both hornet and honeybee) in ImmunoCAP and the passive BAT were determined.ResultsHigh IgE reactivity was seen with the five allergens in V. affinis venom; 96% (29/30) for 34 and 24 kDa, 93% (28/30) for 45 kDa and 90% (27/30) reactivity for the 100 and 80 kDa respectively. IgE cross-reactivity was low with ImmunoCAP using V. vulgaris venom (43%; 13/30) and Ves v1 (3%; 1/30), but relatively high with Ves v5 (73%; 22/30). All patients (100%) were positive to V. affinis venom in passive BAT. In ImmunoCAP, a high double-positivity rate (76%; 23/30) was detected while no double-positivity was detected in passive BAT.ConclusionsHigh IgE reactivity for five allergens of V. affinis points to the potential of using these allergens in component resolved diagnosis (CRD). The passive BAT has shown its importance as a promising diagnostic tool with high accuracy. It would be particularly useful in cases with doubtful double-positive results of other diagnostic tests.

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