CONTACT dermatitis and IgE-mediated reactions to decorative plant species (hyacinth and easter lily) and after inhalation and/or ingestion of Liliaceae family plant foods (salsaparilla, garlic, asparagus, and leek) have been previously described (1-8). The Liliaceae family contains about 3700 species and 250 genera (1). We report a case of acute urticaria and rhinoconjunctivitis induced by contact with airborne particulates of yucca leaves, associated with immediate skin reactions and specific IgE antibodies. Yucca (Yucca filamentosa), a plant of the Liliaceae family, is native to Central America, but is very well adapted to Italy, where it is common as a decorative indoor and outdoor plant. A 38-year-old male nurse reported slight angioedema of the eyelids, urticaria, and itching of the face in his garden while working very close to a yucca plant. A month later, he suffered from an outbreak of acute urticaria-angioedema of the face and the neck and rhinoconjunctivitis after trimming a yucca plant. Prompt treatment with antihistamines and steroids I.M. relieved the symptoms. After this episode, he had no further contact with this plant. Two years later, when he was studied for this reaction, his case history was negative for inhalant or food allergic diseases, as was the skin prick test with a large panel of inhalant and food (such as onion, garlic, and asparagus) commercial extracts (Lofarma Milano, Italy) was negative. The prick by prick test was performed with raw yucca leaves and flowers of yucca in our patient and in 10 controls (six atopic and four nonatopic); saline solution and histamine (10 mg/ml) were used as negative and positive controls, respectively. A wheal at least 3 mm larger than the negative control was considered to be positive. The prick by prick test with yucca leaves, but not flowers, elicited a strong wheal and flare reaction in our patient (8 mm), but both were negative in the control subjects. Serum total IgE was 52 kU/l (CAP System, Pharmacia, Sweden). Specific IgE to yucca leaves was detected with RAST, which was performed with the commercial kit Sferikit IgE (Lofarma SpA, Milan, Italy). The solid phases were polystyrene beads sensitized with an extract obtained with yucca leaves and yucca flowers. The allergenic extract was especially prepared at 5% w/v in PBS (0.15 M), pH 7.2, by the following procedure: . 5 g of yucca leaves or yucca flowers in 100 ml of PBS . extraction overnight at room temperature with stirring . centrifugation at ,25 000 g for 15 min . supernatant prefiltered and dialyzed against PBS containing Thimerosal in a tube with cutoff of 3500 Da at 48C for 24 h . filtration with 0.8-mm Millipore filters. With this extract, the solid phase was prepared, and we detected specific IgE to yucca leaves in the patient's serum: a positivity of class 2 was obtained, and the IgE content was 3.4 RAST AU (arbitrary units). No positivity was obtained with yucca flowers. The patient's IgE reactivity to both yucca leaf and flower extracts was assessed by immunoblot. There was no speci...
