Case report
Rhinoconjunctivitis and asthma caused by cornplant (Dracaena fragrans)Francisco Feo Brito, MD*; Pilar Mur, MD†; Borja Bartolome, PhD‡; Elisa Gomez, MD*;Pedro A. Galindo, MD*; Jesus Borja, MD*; and Ana Alonso, MD*
Background: Respiratory symptoms caused by decorative flowers have seldom been reported in the literature.Objective: To describe a housewife who experienced episodes of asthma, rhinoconjunctivitis, and contact urticaria in relation
to corn plant (Dracaena fragrans) in her home.Methods: Skin prick testing (SPT) was performed with extract from the leaves of D fragrans and a standard battery of
aeroallergens. An air sampler was installed close to the plant in her house. We performed skin, conjunctival, and bronchialprovocation tests with the extract of D fragrans. Serum specific IgE was measured using enzyme allergosorbent testing.
Results: The patient showed positive SPT reactions to the D fragrans extract at a concentration of 0.05 mg/mL. Results ofSPT with the extract prepared from the Air Sentinel filter were also positive. Skin provocation testing with the leaves of cornplant on the patient’s forearm provoked dense wheal formation. The conjunctival provocation test response was positive to anantigen concentration of 0.05 mg/mL. The peak expiratory flow rate varied by 20% to 40% on exposure days and by 5% to 10%on nonexposure days. The bronchial provocation test response was positive to an antigen concentration of 0.5 mg/mL. SpecificIgE to D fragrans extract was 15.1 kUA/L.
Conclusions: These findings strongly suggest that an IgE-mediated immunologic mechanism is responsible for the patient’srespiratory and cutaneous symptoms in relation to corn plant.
Ann Allergy Asthma Immunol. 2007;98:290–293.
INTRODUCTIONSubstances derived from plants are common causes of occu-pational respiratory allergy. These substances include differ-ent types of wood, cereal flour, coffee beans, latex, plantfood, and enzymes.1,2
The Liliaceae family is extensive, including approximately4,000 species in 280 genera, and is formed principally ofgrasses with bulbs (Allium sativum), lianas (Smilax aspera),and trees (Dracaena draco). They may be found all over theplanet except in the arctic.3 Some species of the Liliaceaefamily, such as the tulip, hyacinth, and white and coloredlilies, have long been popular decorative plants and arecauses of skin and respiratory allergy.4,5
Other genera of Liliaceae include decorative species suchas corn plant (Dracaena fragrans). This includes approxi-mately 40 tropical species from Africa and Asia that, ingeneral, have the appearance of a palm. They are character-ized by a straight, woody trunk from which dark green leaves
sprout. In suitable humidity and temperature conditions, theycan produce highly aromatic flowers, from which the namefragrans is derived.
The aim of this study is to describe a patient with asthma,rhinoconjunctivitis, and contact urticaria caused by corn plant(D fragrans) documented on the basis of the clinical history,skin prick test (SPT) results, specific IgE levels, specificbronchial and conjunctival challenge test results, and dailypeak flow measurements during the symptomatic period.
CASE REPORT AND METHODSA 54-year-old woman with no personal or family history ofatopy who, for 2 years, had ocular and nasal pruritus, con-junctival hyperemia, sneezing, hydrorrhea, coughing, tight-ness of the chest, and wheezy dyspnea. The episodes wereinitially sporadic but in the previous 6 months had increasedin frequency and intensity, with exacerbations occurring 4 to6 hours after cleaning a D fragrans plant in her house (on 3occasions she required emergency medical treatment forasthma crises). Furthermore, contact with the plant gave riseto itchy wheals, predominantly on the hands and forearms,which resolved spontaneously within 20 to 30 minutes.
Preparation of Corn Plant ExtractLeaves from corn plant (D fragans) were ground into smallpieces, defatted, and extracted by means of magnetic stirringin agitation in 50-mmol/L phosphate-buffered saline at pH
* Allergy Section, General Hospital, Ciudad Real, Spain.† Allergy Unit, Hospital Santa Barbara, Puertollano, Spain.‡ R&D Department, Bial-Arıstegui, Bilbao, Spain.This work was supported by grant GC 04010 from Instituto de Ciencias dela Salud de Castilla-La Mancha (Spain).Received for publication June 22, 2006.Received in revised form July 17, 2006.Accepted for publication July 27, 2006.
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7.5 during 4 hours at room temperature. The sample wascentrifuged at 5,600g for 30 minutes, and the supernatant wasdialyzed against water. The dialyzed extract was filteredthrough a membrane with 0.22-�m-diameter pores andfreeze-dried.
Skin TestsThe SPTs were performed according to the method describedby the Subcommittee on Skin Tests of the European Acad-emy of Allergology and Clinical Immunology using standard-ized lancets (Dome Hollister Stier, West Haven, CT)6; 1sterile device was used for each test. Histamine phosphate (10mg/mL) and sterile 0.9% saline were used as positive andnegative controls, respectively. A mean wheal area of 7 mm2
or greater compared with the negative control, 15 minutesafter puncture, was considered a positive response.
Initially, SPT was performed with a standard battery ofaeroallergens, including mites (Dermatophagoides pteronys-sinus and Dermatophagoides farinae), fungi (Alternaria al-ternata, Cladosporium herbarium, and Aspergillus fumiga-tus), cat and dog dander, and pollens from Gramineae(Lolium perenne, Dactylis glomerata, and Cynodon dac-tylon), Oleaceae (Olea europaea), Chenopodiaceae (Chenop-odium album and Salsola kali), Plantaginaceae (Plantagolanceolata), and Compositae (Artemisia vulgaris). This wasfollowed by SPT with the extract of D fragrans leaves atserial concentrations, starting at 5 mg/mL (wt/vol). Skinprovocation tests were performed with D fragrans by rubbingthe leaves of the plant on the patient’s forearm for 10 min-utes.
A high-volume air sampler (Air-Sentinel; Quan-Tec-AirInc, Rochester, MN) was installed close to the D fragransplant in the patient’s home. Using Teflon filters, a sample wascollected after 8 hours of exposure. An extract was preparedfor SPT using the material obtained.
Conjunctival and Bronchial Provocation TestsThe conjunctival provocation test was performed with Dfragrans extract according to the method described by Molleret al.7 Serial dilutions were prepared at 0.005, 0.05, 0.5, and5.0 mg/mL of D fragrans extract. A nonspecific BPT withmethacholine was performed using the procedure and con-centrations proposed by Chatham et al.8 To evaluate therelationship of the plant with the patient’s asthma, peak flowwas measured daily in the home for 4 weeks, recording thedays of exposure. A specific BPT was performed with Dfragrans extract according to the method described by Chai etal.9 The patient underwent skin testing at concentrations of0.005, 0.05, 0.5, and 5.0 mg/mL of D fragrans extract todetermine a safe starting dose for the provocation test; thisextract concentration was of 0.005 mg/mL (10-fold lowerthan the concentration that produced a 3 � 3-mm wheal). Thepatient inhaled the aerosolized allergen in progressively in-creasing concentrations (0.005, 0.05, 0.5, and 5.0 mg/mL) for2 minutes at tidal volume. The forced expiratory volume in 1second (FEV1) and peak expiratory flow rate (PEFR) were
measured after each inhalation period and also at 5, 10, 15,30, and 60 minutes. To evaluate the bronchial late response,the patient herself monitored PEFR values in parallel withspirometry recordings taken using a portable peak flow meter(Mini-Wright; Clement Clarke International, Harlow, En-gland) for up to 24 hours. The SPTs, conjunctival provocationtests, and BPTs were also performed on a group of controlsubjects (3 nonatopic individuals and 3 allergic to pollen).
Specific IgE DeterminationSerum specific IgE to D fragrans extract was measured usingan enzyme allergosorbent test (EAST) with the allergen cou-pled to cyanogen bromide–activated paper discs (0.4 mg perdisc). Measurement of specific IgE to other common localaeroallergens (pollen from L perenne, O europaea, S kali, Avulgaris, and Brassia verrucosa) was performed using theCAP System (UniCAP; Pharmacia & Upjohn DiagnosticsAB, Uppsala, Sweden). The cross-reactivity studies wereperformed by means of EAST inhibition assays, as previouslydescribed. The D fragrans extract was used as solid phase(inhibited) and the same extract and pollen extracts from Oeuropaea, L perenne, and B verrucosa as free (inhibitor)phases.
RESULTSThis patient showed positive SPT reactions to the D fragransleaf extract at a concentration of 0.05 mg/mL. The SPTresponses to a battery of commercially available commoninhalants were positive to pollen from O europaea, A vul-garis, and S kali. The SPT reaction with the extract preparedfrom the Air Sentinel filter was also positive. Skin provoca-tion testing with the leaves of D fragrans on the patient’sforearm provoked dense wheal formation at 20 minutes. Theconjunctival provocation test response was positive to anantigen concentration of 0.05 mg/mL.
Peak flow monitoring on days with and without exposureindicated occupational asthma; the PEFR varied by 20% to40% on exposure days and by 5% to 10% on nonexposuredays, although the patient used regular budesonide, 800-�ginhalations, and salbutamol, 200 �g/d. The BPT responsewas positive to an antigen concentration of 0.5 mg/mL,observing declines in the FEV1 to 32% and in the PEFR to44% (Fig 1). No delayed reaction was detected using the peakflow meter during the 24 hours after BPT. The nonspecificBPT response to methacholine was also positive (provocationdose that caused a decrease in FEV1 of 20% � 150 AU) 24hours after specific BPT. None of the control subjects had apositive response to SPTs, conjunctival provocation tests, orBPTs.
Serum specific IgE to D fragrans extract was positive(15.1 kUA/L, class 3) with patient serum and negative(�0.35 kUA/L) with control serum (a pool of sera fromnonatopic individuals). Specific IgE to common aeroaller-gens was negative to L perenne, O europaea, S kali, Avulgaris, and B verrucosa. The EAST inhibition assay, per-formed with D fragrans as solid phase, showed 90% inhibi-
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tion when the same extract was used as inhibitor phase,whereas when pollen extracts from O europaea, S kali, Avulgaris, and B verrucosa were used as inhibitors, an inhibi-tion value of less than 10% was obtained.
DISCUSSIONWe describe a housewife who experienced episodes ofasthma, rhinoconjunctivitis, and contact urticaria related to acorn plant (D fragrans) in her home (Fig 2). The dustyenvironment created by cleaning the plant induced immediaterhinoconjunctivitis and contact urticaria and asthma crises at
4 to 6 hours that required emergency treatment on 3 occa-sions. The results indicate an IgE mechanism (IgE-mediatedasthma, rhinoconjunctivitis, and contact urticaria) demon-strated by SPT, specific IgE determination, and provocationtesting (skin, conjunctival, and bronchial) to D fragrans ex-tract. The PEFR monitoring demonstrated the associationbetween her symptoms and her plant hobby.
Corn plant allergy has not been reported. However, Kan-erva et al10 performed SPT with several decorative plants inmore than 600 patients. The study showed that corn plant (Dfragrans) caused a 4.6% rate of positive SPT reactions. Theclinical relevance of the individual SPT reactions was notspecified. Other decorative plants, such as carnation (Di-anthus caryophyllus)11 and dried flowers (Limonium tatari-cum),12 have also been reported as occupational allergens inflorists, gardeners, and plant cultivators. Decorative plantshave been considered a safe alternative for allergic people,but they too may cause allergy. An extensive series of theFinish Register of Occupational Diseases between 1982 and1994 found 31 cases of occupational allergic rhinitis and 15cases of occupational asthma.13
In occupational allergy due to plants, the pollen and thepollen particles released into the workplace environment areresponsible for the allergic symptoms in exposed workers, asoccurs with saffron (Crocus sativus)14 on separating the stig-mas from the rest of the flower. However, the allergeniccapacity of the plants is not limited to the pollen grains, asother parts of its structure (such as antigens from inflores-cences, leaves, stems, or seeds) also have the capacity toinduce allergic responses.15 In the present patient, the dustyenvironment created by the cleaning of the leaves was re-sponsible for the symptoms of the patient who, furthermore,did not have any professional activity. She was a housewifewho included the care and cleaning of the D fragrans plantamong her tasks, and it was this hobby that gave rise to herallergic symptoms. In conclusion, we present a new indoorallergen derived from a plant that does not produce pollen,demonstrating that this type of plant is not completely safe foratopic individuals.
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Figure 1. Forced expiratory volume in 1 second (FEV1) and peak expi-ratory flow rate (PEFR) recordings after inhalation of 0.5 mg/mL (wt/vol) ofcorn plant (Dracaena fragrans) extract.
Figure 2. A corn plant (Dracaena fragrans) at the patient’s home. Next tothe plant is the Air Sentinel (high-volume air sampler), a device that collectsthe aeroallergens from D fragrans in the filter. It operates at 60 L/min.
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Requests for reprints should be addressed to:Francisco Feo Brito, MDAllergy SectionGeneral HospitalC/ Tomelloso s/n13004 Ciudad Real, SpainE-mail: [email protected]
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