Allergy to weeping fig--a new occupational disease

High incidence of sensitization to ornamental plants in allergic rhinitis

BACKGROUND

A few indoor plants have been described as potential allergens, in single case reports of allergic rhinitis. There is no data evaluating the prevalence of allergic sensitization to these plants.

AIM

The relationship between owning indoor ornamental plants with the risk to be sensitized has been evaluated in atopic rhinitis.

METHODS

A group of 59 patients with allergic rhinitis were submitted to skin prick tests (SPT) using both the leafs of their own plant and commercial extracts of the most frequent airborne allergens. A control group of 15 healthy subjects was tested with the same allergens.

RESULTS

While no subject from the control group developed a significant SPT to any of the tested plants, 78% of allergic rhinitis had positive SPT to at least one plant, the most frequent sensitization being Ficus benjamina, yucca, ivy and palm tree.

CONCLUSION

In allergic rhinitis, indoor plants should be considered as potential allergens.

Allergische Kontakturtikaria durch ein Chamäleon

A 31-year-old man presented with a long history of rhinoconjunctivitis and sneezing that lasted from March to May. The man kept a chameleon (Chamaeleo calyptratus) as a pet and reported about recurrent urticarial lesions, erythema, and itch after skin contact with the animal. The reactions started within a few minutes and were restricted specifically to the contact sites with the animal's claws. No comparable reactions occurred in other subjects. Allergy testing confirmed allergy to hazel, alder, birch, and ash pollen, and additionally revealed sensitization to house dust mite, cat, and Ficus benjamina. Apparently the contact dermatitis originated from passive transfer of Ficus benjamina allergens to the patient's skin by the reptile which habitually climbed on a big Ficus benjamina tree in the patient's home, thereby contaminating its claws with the plant's allergenic milky sap. Careful examination revealed strong perforation of many leaves by the pointed claws. The patient denied respiratory symptoms from Ficus benjamina and intolerance of Ficus-associated fruits.

Sensitization to Ficus benjamina: relationship to natural rubber latex allergy and identification of foods implicated in the Ficus-fruit syndrome

BACKGROUND

Ornamental Ficus benjamina (FB) has been recognized as a new indoor allergen. Little is known about the prevalence in moderately exposed subjects and the proposed association with fruit and Hevea latex hypersensitivity.

OBJECTIVE

To study the prevalence of FB sensitization and the relationship with Hevea latex allergy, to identify cross-reacting fruits, and to characterize the responsible allergens.

METHODS

A skin prick test solution prepared from FB latex (200 microg/mL) was included in our routine screening programme for suspect inhalant allergy. Patients reacting with the FB extract were further skin tested with exotic fruits by the prick-to-prick method. Inhibition of fig and FB CAP by FB latex, fig (Ficus carica), kiwi, the thiolproteases ficin and papain, Hevea latex and rHev b 6.02 (hevein) was performed in selected patients.

RESULTS

Of 2662 patients with a positive skin test to any aeroallergen, 66 (2.5%) reacted with FB. Ten patients showed isolated sensitization to FB. Although FB-positive subjects were more often co-sensitized to Hevea latex than FB-negative (10.6% vs 3.8%, P< 0.01), nearly 90% tested negative for Hevea latex. Sensitization to FB was specifically associated with positive skin tests to fresh fig (83%), dried fig (37%), kiwi fruit (28%), papaya (22%), avocado (19%), banana (15%), and pineapple (10%) (n = 54). Clinical reactions were reported mainly from fresh and dried fig and kiwi (47%, 60%, and 64%, respectively, of skin test-positive patients), including seven patients with systemic reactions (urticaria, angiooedema, asthma). CAP to fig in 11 patients with clinical fruit allergy was inhibited on average by 87% by FB latex, 89% by fresh fig, 80% by dried fig, 38% by kiwi (100 microg/mL each), and by 59% and 44% by ficin and papain (50 microg/mL), respectively. No inhibition was obtained with Hevea latex and rHev b 6.02. CAP to FB was inhibited on average by 95% by FB, 60% by fresh fig, 41% by ficin, 29% by papain, and less than 7% by rubber latex allergens.

CONCLUSIONS

Sensitization to FB latex is found in 2.5% of atopic individuals and mostly occurs independently of Hevea latex allergy. Sensitization is commonly associated with allergic reactions to figs and other tropical fruits ('Ficus-fruit syndrome'). This cross-reactivity is mediated at least in part by thiolproteases.

A history of latex allergy

Archaeologists have found that latex items were used as early as 1600 BC, but it took until approximately 1900 AD before surgical gloves were commonly used. Descriptions of apparent allergic reactions to natural rubber appeared in the medical literature in 1927, and irritant and delayed-contact reactions were reported in 1933. Although irritant and delayed-contact reactions to rubber products were increasingly recognized, immediate-type allergic reactions were not reported again until 1979. However, after 1980, increasing numbers of contact urticarial reactions to latex were reported, and investigations suggested that many of these reactions were IgE-mediated. In 1984, the first anaphylactic reactions caused by latex surgical gloves were reported, followed in 1991 by the first report of a fatal anaphylactic reaction to latex. Increasing recognition of latex allergy led to divergent paths of investigation. Critical early questions were whether the observed reactions were truly IgE-mediated, and if they were IgE-mediated, what was the source of the allergen? If the allergen was present in latex products, where did it come from? Was it present in raw latex or was it added during processing? As knowledge about the allergens improved, efforts were made to develop and test materials for skin testing and for allergen-specific IgE assays. Now more than 10 unique proteins are recognized as major latex allergens. Although much has been learned about latex allergy, important unanswered questions remain, including the sources of latex exposure that led to sensitization, why latex allergy increased dramatically during the 1980s, and the prevalence of latex allergy in diverse populations. This review concentrates on the history of latex use in medicine and the dramatic emergence of immediate-type latex allergy.

Occupational allergic contact urticaria to yucca (Yucca aloifolia), weeping fig (Ficus benjamina), and spathe flower (Spathiphyllum wallisii)

BACKGROUND

Occupational contact urticaria (CU) from plants is often reported, but it is less often attributed to decorative houseplants. We present an atopic gardener and caretaker of plants who developed CU when occupationally exposed to weeping fig, spathe flower, and yucca.

METHODS

Sensitization was evaluated by skin prick tests (SPT) and analyses for IgE antibodies.

RESULTS

SPT were positive to all three plants, and IgE antibodies were found to weeping fig and spathe flower. SPT were also performed with several decorative houseplants in more than 600 patients. Positive SPT was found to weeping fig (12%), African milk tree (8.3%), yucca (5.8%), Chinese rose (4.7%), massangana (4.6%), bird's nest fern (3.2%), and spathe flower (3.2%).

CONCLUSION

Our study indicates that SPT and tests for IgE antibody are useful in detecting occupational CU caused by houseplants.

Asthma caused by Ficus benjamina latex: evidence of cross-reactivity with fig fruit and papain

BACKGROUND

Ficus benjamina or weeping fig is a plant used increasingly for indoor decoration that can cause allergic rhinitis and asthma.

OBJECTIVE

We report a clinical and immunologic study in a patient with perennial asthma caused by F. benjamina latex in whom several episodes of angioedema of the oropharyngeal tract and tongue followed ingestion of figs and kiwi.

METHODS

Hypersensitivity to latex from F. benjamina and from Hevea brasiliensis, fig fruit, kiwi, papain, and bromelain was investigated by means of skin prick test, specific IgE determination by CAP, histamine release test, and bronchial provocation test to F. benjamina latex. CAP-inhibition assays were carried out to study possible cross-reactivity among these antigens.

RESULTS

Hypersensitivity to F. benjamina latex, fig, kiwi, and proteases was demonstrated by means of skin prick test, determination of specific IgE and histamine release test. Bronchial provocation test with F. benjamina latex resulted in a dual asthmatic reaction, confirming the etiologic role of this plant. A rise of eosinophil cationic protein in patient's serum was observed 21 hours after bronchial challenge, suggesting activation of eosinophils. Inhibition assays showed that F. benjamina latex as liquid-phase inhibited up to 95% the CAP to fig and up to 57% the CAP to papain. Neither sensitization nor cross-allergenicity with H. brasiliensis latex was found.

CONCLUSIONS

Hypersensitivity to F. benjamina latex may cause IgE-mediated respiratory allergy. The association with allergy to fig and papain is likely due to the existence of cross-reactive allergen structures.

Occupational type I allergy to Christmas cactus (Schlumbergera)

The study aimed to determine whether occupational contact urticaria and symptoms of mucous membranes, reported by five workers in a cactus nursery, were due to IgE-mediated allergy to Schlumbergera cacti. The five persons had positive skin prick tests to the plants as is and positive histamine-release tests, and in three of them specific IgE to the cacti could be demonstrated by Maxisorp RAST and immunoblotting. Four of the patients were atopic, and the fifth had a positive skin prick test to cat dander, indicating latent atopy. Skin prick tests with cacti were negative in most atopic volunteers, and all had negative histamine-release tests. The results suggest a true IgE-mediated allergy to the cacti, and both genetic predisposition and close contact with the plants at work seem to be important factors in the emergence of this new occupational allergy.

Allergy to the ornamental indoor green plant Tradescantia (Albifloxia)

We report on a 32-year-old atopic female office employee with a moderate tree pollinosis who also suffered from indoor-related perennial rhinoconjunctivitis. Once when she repotted her two ornamental nonflowering green plants of the genus Tradescantia (synonym; Albifloxia; family Commelinaceae), she immediately experienced itching of the face, throat, and conjunctiva; swelling of the lips; and dyspnea and wheezing. Skin prick tests with the leaves of Tradescantia (T. albifloxia and T. fluminensis) (Ta and Tf) were strongly positive as was the specific IgE to Ta leaves extract. On RAST inhibition studies, no cross-reactivity was found between Ta and Ficus benjamina (weeping fig), a nonflowering green plant, which produces, in its milky sap, an important respiratory allergen. Green plants should be considered potential indoor allergens and tested in plant-keepers referred for allergologic investigation.

First report of anaphylactic reaction after fig (Ficus carica) ingestion

We report an anaphylactic reaction which occurred very shortly after ingestion of a fresh fig. The IgE-dependent mechanism was demonstrated on the basis of positivity of the prick test performed with fresh fig (Ficus carica) extract. In addition, we were able to detect specific IgE to the same extract in the serum. The patient did not demonstrate sensitization to other common allergens involved in respiratory and food allergies. However, detection of specific IgE to F. benjamina indicated a sensitization to weeping fig. The CAP F. benjamina was partially inhibited by preincubation of the serum with fig extract, suggesting that these two species of Ficus share some common allergens. In this context, the assumption can be made that weeping fig was responsible for the initial sensitization in this patient.

The allergen of Ficus benjamina in house dust

Ficus benjamina, a member of the Moraceae family, is a tropical, non-flowering green plant which is widely used for ornamental purposes. It is an occupational allergen in plant keepers but sensitization is also increasingly found in non-occupationally exposed atopic and non-atopic patients. The allergen of Ficus benjamina is located in the plant sap, a so-called latex. By radioallergosorbent test-(RAST)-inhibition studies allergen could also be demonstrated in the dust collected from the leaf surface and in dust samples from the floor of rooms where the plant was placed. These findings could result in more extensive preventive measures in patients sensitized to Ficus benjamina. In addition there is some evidence that possibly a crossreactivity between latex of Ficus benjamina and latex from the rubber tree Hevea brasiliensis, a member of the Euphorbiaceae family, may exist.

Occupational asthma caused by decorative flowers: review and case reports

Occupational respiratory symptoms caused by decorative flowers are seldom reported in the literature. In the years 1985-1993 four such cases of occupational asthma were diagnosed at the Institute of Occupational Health of Finland. Occupational asthma was caused by freesias (n = 1), chrysanthemums (n = 1), and tulips (n = 2). The diagnoses were based on work-related respiratory symptoms during flower handling in the patients' histories, specific challenge tests, and allergologic examinations. Flower allergy is rare but can even develop into occupational asthma. It usually leads to a change of profession.

Severe isolated allergy to Ficus benjamina after bedroom exposure

Allergies to Ficus benjamina (Fb, weeping fig) have been described first as an occupational disease in plant keepers and later in clearly atopic subjects with known sensitizations to other inhalant allergens. We report a case of a hitherto nonatopic man with allergic rhinoconjunctivitis, contact urticaria, and asthma caused by a Fb kept in his bedroom for 18 months. Rubbing and skin prick test with native fig leaves and sap, and RAST to Fb were clearly positive. No other sensitization could be detected. After eliminating his Fb, he became asymptomatic within a few months. This case shows that private close contact to Fb can also induce allergy even in hitherto nonatopic subjects. Therefore, Fb should not be kept in bedrooms.

Serum reactivity to other indoor ficus plants in patients with allergy to weeping fig (Ficus benjamina)

Ornamental plants have long been used for indoor decoration. An example is the india rubber tree (Ficus elastica). With the increased popularity of green plants, both in private homes and public premises, small-leaf species, such as weeping fig or Ficus benjamina (Fb), have become widely used. Exposure to dust from Fb may cause sensitization and allergic airway symptoms, which among occupationally exposed plant keepers occur both in atopics and non-atopics. The serum reactivity to sap extracts from Fb and seven other indoor plants of the genus Ficus were investigated with RAST and a RAST inhibition technique, using sera from 12 atopic subjects and 12 plant keepers, sensitized to Fb. The allergenic similarity between the different extracts was found to be extensive. The specific IgE antibodies with the highest concentrations in serum were those against Fb and its variegate form, "star light", with decreasing values for the other species, especially those with larger leaves. The binding of IgE antibodies to the other Ficus RAST discs could be completely inhibited by extract of Fb. These reactions were probably due to cross-reactivity. Sensitization is believed to occur by inhalation of allergen-enriched dust, emanating from the leaves of the plants. The high allergenic potency of the species with many small leaves may be due to their large total leaf area.

Flowers and other trigger factors in asthma and rhinitis--an inquiry study

Six hundred and eighty adult patients with asthma and/or rhinitis were questioned about symptoms elicited by 46 different flowers and 10 common non-specific environmental trigger factors listed in a questionnaire. Flowers or birch twigs were reported to elicit symptoms in 79% of the patients, somewhat more often in rhinitis than in asthma patients, and caused symptoms as often in non-atopics as in atopics. Birch twig and marguerite most frequently induced symptoms, followed by strongly smelling flowers such as hyacinth, lilac, and lily of the valley. Unspecific irritants caused symptoms in 98% of the asthmatics and in 67% of patients with rhinitis. Tobacco smoke and perfumes were the most important troublemakers. A significant positive correlation was found for elicitation of symptoms from flowers and from certain non-specific irritants. It is concluded that non-specific hyperreactivity as well as reaginic hypersensitivity are the mechanisms involved when birch twigs and flowers elicit symptoms.

Occupational allergy to weeping fig in plant keepers

Plant keepers take regular care of green plants in public buildings and offices. One of the most common green plants in Scandinavia is weeping fig (Ficus benjamina). We have previously reported on two plant keepers sensitized to this plant, one had asthma and the other allergic rhinitis. We now report a study of four plant-leasing firms employing 60 plant keepers and 24 less exposed. Positive RAST and skin tests in 16 of the plant keepers and two of the employees showed them to be sensitized. All sensitized subjects suffered from conjunctivitis and/or rhinitis and six had asthma. Handling of green plants is a new example of an occupation which may cause IgE-mediated allergy.