Acta Dermato-Venereologica, issue 9 97-9CompleteContent | Page 22

1134 SHORT COMMUNICATION Rare Ingestive Food Allergy to Mushroom Boletus badius Tatjana FISCHER, Bernadette EBERLEIN, Knut BROCKOW, Markus OLLERT, Johannes RING and Ulf DARSOW Department of Dermatology and Allergy Biederstein, Technische Universität München, Biedersteiner Str. 29, DE-80802 München, Germany. E-mail: [email protected] Accepted Jun 8, 2017; Epub ahead of print Jun 9, 2017 Food allergy can occasionally be severe and difficult to diagnose, especially in the event of a rare allergen. We de- scribe here a case of severe immediate-type anaphylaxis to bay bolete mushroom, which demonstrates the value of basophil activation testing (BAT) in the diagnosis of rare food allergies in which there is a lack of specific IgE (sIgE) and high risk of oral challenge testing. CASE REPORT A 25-year-old woman experienced a systemic anaphylactic reac- tion in September 2014 after eating a mushroom omelette made of eggs, bay bolete mushrooms that she had collected, parsley, salt and pepper. Thirty minutes after eating, the patient developed generalized urticaria, pruritus of the oral and nasal mucous mem- branes, dysphagia, feeling of obstruction in the throat and dysp- noea (anaphylaxis grade 2–3 according to Ring and Messmer’s classification). The symptoms ceased after administration of an anti-allergic treatment. Other foods that the patient had consumed that day had been eaten again and tolerated since the incident. Cofactors, such as infections, alcohol consumption or physical exertion, were not present. The patient had a history of grass-pollen induced allergic rhinoconjunctivitis status post-immunotherapy (sublingual immunotherapy; SLIT for a 3-year course) with only minor symptoms at the time of examination, atopic eczema, allergy to animal hair (horse, cat and dog epithelia), oral allergy syndrome to walnuts, and immediate-type hypersensitivity to ciprofloxacin. Skin prick test (SPT) to aeroallergens, spices and nutritive al- lergens, as well as prick-to-prick tests to the mushroom omelette using the same ingredients as the original omelette, bay bolete (Boletus badius, Fig. S1a 1 ), porcino mushroom (Boletus edulis, Fig. S1b 1 ), shiitake, portobello, horse, chanterelle and oyster mushrooms were carried out one year after the anaphylactic reaction. Total IgE and sIgE were also performed. Furthermore, a flow cytometric basophil activation test (BAT) measuring CD63 expression (Flow CAST ® ) with bay bolete was carried out. Frozen and pestled Boletus badius diluted with stimulation buffer (equally weighted) was used at a 1:25 and 1:100 dilution. Higher concentrations of bay bolete could not be tested, due to the mucous texture of the mushroom and buffer mixture. A healthy control was also tested with the BAT. An immunoblot with the bay bolete extract was performed. Ultimately, unblinded oral chal- lenge tests (OCT) using increasing dosages with the fully cooked omelette seasoned with salt, pepper and parsley (without Boletus badius), with chanterelle and brown wood mushrooms as well as Boletus edulis was conducted outside of the grass pollen season. Oral challenge with the suspected mushroom as well as the skin test positive mushrooms was omitted due to the severity of the original anaphylactic reaction. https://www.medicaljournals.se/acta/content/abstract/10.2340/00015555-2721 1 doi: 10.2340/00015555-2721 Acta Derm Venereol 2017; 97: 1134–1135 RESULTS SPT was positive to pollen from tree mix I and II, hazel, alder, birch, olive, grass mix, herbs, mugwort and ash, other aeroallergens, such as Cladosporium, Aspergil- lus, dog, cat, rabbit and guinea pig epithelia, as well as spices, such as garlic, cilantro, curry, and other nutritive allergens, such as hazelnut, apple, walnut, almond, barley flour, and hops. Other perennial and seasonal aeroal- lergens, spices (native), foods, nuts (native) and flour, brain and yeast types (native) tested negative. Prick- to-prick test was positive to the homemade mushroom omelette, raw bay bolete, shiitake, oyster and portobello mushroom. Egg, parsley, porcino, brown wood and chan- terelle mushrooms tested negative in the PPT. Detailed results are shown in Table I. Total IgE level was 341 IU/ ml and sIgE was positive to timothy (> 100 KU/l) and birch tree pollen (11.1 KU/l), cat epithelium (23 KU/l) and hazelnut (1.24 KU/l). SIgE was negative to other food allergens and pollen, including rPhl p7, rPhl p12 and rBet v2, as well as to CCD MUX F3 Bromelain. Flow cytometric BAT showed a positive reaction to bay boletus (bay boletus concentration 1:25 % CD63 91.75%; concentration 1:100 % CD63 86.13%; see Table SI 1 ). A healthy control tested negative to the concentrations used. Immunoblotting analysis indicated the specific bands at 25, 35, 50, 60 and 150 kDa (Fig. S2 1 ). In the OCT, the homemade omelette without bay bolete, and the sautéed brown wood, chanterelle and porcino mushrooms were tolerated. Based on the patient’s history of a grade 2–3 anaphy- laxis according to Ring and Messmer after ingestion of a bay bolete omelette and the findings in the laboratory and skin tests as well as the OCT, we confirmed the Table I. Skin prick test results (diameter of wheals) of tested mushroom allergens. Positive result defined as wheal diameter ≥3 mm (bold) Allergens Wheal size, mm Mushrooms (native) Shiitake mushroom Oyster mushroom Boletus edulis Chanterelle mushroom Boletus badius Brown wood mushroom Portobello mushroom Mixed mushroom omelette Controls Hi stamine NaCl 0.9%   3 3 0 1 7 1 4 4 6 0 This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta Journal Compilation © 2017 Acta Dermato-Venereologica.