Patterns of anaphylaxis after diagnostic workup: A follow-up study of 226 patients with suspected anaphylaxis

BACKGROUND

Most published studies on anaphylaxis are retrospective or register based. Data on subsequent diagnostic workup are sparse. We aimed to characterize patients seen with suspected anaphylaxis at the emergency care setting (ECS), after subsequent diagnostic workup at our Allergy Center (AC).

METHODS

Prospective study including patients from the ECS, Odense University Hospital, during May 2013-April 2014. Possible anaphylaxis cases were daily identified based on a broad search profile including history and symptoms in patient records, diagnostic codes and pharmacological treatments. At the AC, all patients were evaluated according to international guidelines.

RESULTS

Among 226 patients with suspected anaphylaxis, the diagnosis was confirmed in 124 (54.9%) after diagnostic workup; 118 of the 124 fulfilled WAO/EAACI criteria of anaphylaxis at the ECS, while six were found among 46 patients with clinical suspicion but not fulfilling the WAO/EAACI criteria at the ECS. The estimated incidence rate of anaphylaxis was 26 cases per 100 000 person-years and the one-year period prevalence was 0.04%. The most common elicitor was drugs (41.1%) followed by venom (27.4%) and food (20.6%). In 13 patients (10.5%), no elicitor could be identified. Mastocytosis was diagnosed in 7.7% of adult patients and was significantly associated with severe anaphylaxis. Atopic diseases were significantly associated only with food-induced anaphylaxis. Cofactors were present in 58.1% and were significantly associated with severe anaphylaxis.

CONCLUSION

A broad search profile in the ECS and subsequent diagnostic workup is important for identification and classification of patients with anaphylaxis. Evaluation of comorbidities and cofactors is important.

Prospective evaluation of the diagnostic value of sensitive KIT D816V mutation analysis of blood in adults with suspected systemic mastocytosis

BACKGROUND

Sensitive KIT D816V mutation analysis of blood has been proposed to guide bone marrow (BM) investigation in suspected systemic mastocytosis (SM). The aim of this prospective study was for the first time to compare the D816V status of the "screening blood sample" used to guide BM biopsy in suspected SM to the outcome of the subsequent BM investigation.

METHODS

Fifty-eight adult patients with suspected SM were included. The outcome of sensitive KIT D816V analysis of blood was compared to the result of the BM investigation.

RESULTS

Screening blood samples from 44 of 58 patients tested D816V-positive. In 43 of these, SM was subsequently diagnosed in the BM investigation. One patient with a D816V-positive screening sample was diagnosed with monoclonal MC activation syndrome. Screening blood samples from 14 patients tested D816V-negative. SM was subsequently diagnosed in five of these, whereas nine patients did not fulfill any diagnostic SM criteria (excluding tryptase criterion). Of the 48 SM patients, 90% tested D816V-positive. Thirteen SM patients presented with Hymenoptera venom-induced anaphylaxis, no skin lesions, and baseline serum tryptase ≤20 ng/mL. Of these, 92% tested D816V-positive in the screening blood sample.

CONCLUSION

This prospective study demonstrates that a D816V-positive result in a screening blood sample identifies SM among patients with hymenoptera venom-induced anaphylaxis in whom the diagnosis would most probably have been missed, with potential severe implications. The observed false-negative screening results also underline that BM investigation is mandatory in all adult patients with clear signs of, or highly suspected SM, regardless of the KIT mutation status.

Food allergy and food sensitization in early childhood: results from the DARC cohort

BACKGROUND

The prevalence of food hypersensitivity (FHS) and the relationship with atopic dermatitis (AD) is controversial. The aim of this study was to determine the development of FHS and to correlate this with AD in relation to sensitization and symptoms.

METHODS

This study combines new data from birth to 18 months of age with previous published results from 3 and 6 years. The Danish Allergy Research Centre cohort, including 562 children, is a unique, population-based, prospective birth cohort, with clinical examinations at all follow-ups. All children were examined for the development of AD using Hanifin-Rajka criteria and for FHS using interviews, skin prick test (SPT), specific immunoglobulin E (IgE), and food challenge according to EAACI guidelines.

RESULTS

Twenty children were confirmed with FHS to milk, egg, and peanut. FHS peaked at 18 months (3.6%) and then decreased to 1.2% at 72 months of age. No new cases were found after 3 years. Self-reporting could only be confirmed in 31% of cases. Among the 122 children with AD, 18 had FHS (14.8%). FHS was IgE-mediated in 95% of the cases but 16 of 20 children were additionally sensitized to other foods which they tolerated. Children with AD were neither more IgE-sensitized nor had higher levels of IgE when compared with healthy children but they were more persistently sensitized.

CONCLUSIONS

Sensitization to foods in young children without food allergy seems to be a normal phenomenon. The discrepancy between sensitization, self-reported food-related symptoms and confirmed FHS illustrates the need to perform standardized oral challenges in order to confirm the diagnosis of FHS.