Dietary Interventions in Pollen-Related Food Allergy

In practice, it remains unclear what the best dietary approach is in subjects with pollen-related food allergy (PRFA). Our objective was to evaluate the effect of (1) dietary avoidance advice, (2) oral immunotherapy (OIT), (3) (heat) processing, and (4) consumption of hypoallergenic cultivars on frequency, severity, and eliciting dose of pollen-related food allergic reactions. A systematic search was conducted in PubMed, Embase, and Cochrane. All studies performing an in vivo investigation of one of the four interventions in adults with PRFA were included. Each study was assessed for quality and validity. Available data on frequency, severity, and eliciting dose of allergic reactions were extracted. Ten studies matched the eligibility criteria. No studies were retrieved on dietary avoidance advice. Two studies (N = 92) on apple OIT reported that tolerance was induced in 63% and 81% of subjects. Four studies (total N = 116) focused on heat processing. Heating was found to completely eradicate symptoms in 15–71% of hazelnut allergic and 46% of celery allergic individuals. Four studies (N = 60) comparing low to high allergenic apple cultivars revealed that Santana (and possibly Elise) apples seemed to cause milder reactions than Golden Delicious. In the awareness that overall level of evidence was low, we conclude that OIT, heat processing, and hypoallergenic cultivars may diminish or completely prevent allergic reactions in some but not all subjects with PRFA.

Development of a standardized low-dose double-blind placebo-controlled challenge vehicle for the EuroPrevall project

BACKGROUND

  Double-blind placebo-controlled food challenge (DBPCFC) is the gold standard for diagnosing food allergy. Standardized materials and protocols are essential for comparing DBPCFC results for multicentre studies such as EuroPrevall. This required the development and piloting of a standardized vehicle and low-dose protocol for confirming food allergy and determination of minimum eliciting doses (MEDs).

METHODS

  A low-dose DBPCFC protocol was developed, with eight titrated protein doses from 3 μg to 1 g. This was delivered using a simple, microbiologically stable food base incorporating allergenic food ingredients manufactured at three sites and centrally distributed to clinical centres. Allergen blinding was assessed by a professional sensory testing panel using a triangle test. Homogeneity and allergen content were confirmed by ELISA and clinical efficacy was assessed in a pilot study, using celeriac and hazelnut as exemplars.

RESULTS

  Celeriac and hazelnut ingredients were sufficiently blinded in the dessert. The dessert meals were successfully piloted with hazelnut in allergy clinics in Spain, the Netherlands and Italy and with celeriac and hazelnut in Zurich. The challenges elicited a range of subjective and objective reactions ranging in severity from mild itching of the oral mucosa to bronchospasm.

CONCLUSIONS

  A standardized challenge vehicle proven to sufficiently blind processed, powdered hazelnut and celeriac ingredients and that can be reproducibly manufactured has been developed. This pilot study shows that the vehicle is promising for the confirmation of food allergy and determination of MEDs in adults and children with body weight >28.8 kg (approximately 7-11 years old).

Food-dependent exercise-induced anaphylaxis: possible impact of increased basophil histamine releasability in hyperosmolar conditions

We present a case of anaphylactic shock induced by exercise following celery ingestion. The possible mechanism of food-dependent exercise-induced anaphylaxis (FDEIA) and the laboratory tests for its diagnosis are discussed. We evaluated spontaneous, celery-allergen-induced, and anti-FcepsilonRI-antibody-induced histamine release from basophils obtained from the patient, 2 celery-allergic controls, and 3 healthy controls. Buffers of increasing osmolarity were used to mimic conditions of vigorous physical exercise. Only the patient's basophils showed an increase in spontaneous, anti-FcepsilonRI antibody-induced and allergen-induced histamine release under physiological conditions and with slightly increased medium osmolarity. To our knowledge, this is the first report on the possible role of increased histamine releasability in the pathogenic mechanism of FDEIA. We suggest that FDEIA results from increased histamine releasability triggered by physical effort after exposure to a sensitizing food allergen.

Can dietary furanocoumarin ingestion enhance the erythemal response during high-dose UVA1 therapy?

As phototoxic skin reactions caused by psoralen are induced by wavelengths within the UVA1 spectrum, we assessed the potential of the small amount of psoralen in a normal diet to provoke phototoxicity in volunteers with skin types I and II. Threshold erythema was unaffected by ingestion of a 200-g portion of parsnip.

Occupational asthma due to carrot in a cook

BACKGROUND

Few previous reports of carrot-induced asthma have been confirmed by objective tests. Hypersensitivity to carrot is frequently associated with allergy to Apiaceae spices and sensitization to birch and mugwort pollens.

CLINICAL CASE

A 40-year-old cook woman was seen with sneezing, rhinorrhea, contact urticaria and wheezing within few minutes of handling or cutting raw carrots. She needed to leave out of the kitchen while the other cooks cut raw carrots.

METHODS AND RESULTS

Skin tests were positive to carrot, celery, aniseed and fennel. Rubbing test with fresh carrot was positive. Specific IgE to carrot was 4.44 kU/L. Determinations of specific IgE to mugwort, grass and birch pollens were negative. Inhalative provocation test, performed as a handling test, was positive. The IgE-immunoblotting showed two bands in carrot extract: a band with apparent molecular weight of 30 kd and other band of 18 kd. This band of 18 kd was Dau c 1. The band of 30 kd could correspond a phenylcoumaran benzylic ether reductase. Dau c 1 did not appear to be the unique allergen in this case. Additional allergens may induce the sensitization. Primary sensitization due to airborne allergens of foods and the lack of pollen allergy in this patient are notorious events.