The types of plants grown in the home will frequently differ from those grown in the office or workplace, in that the home gardener may well experiment with different types of plants grown in different locations at various times of the year (e.g., growing herbs in an indoor window box with a southern exposure). Similarly, home gardeners with a greenhouse may grow a wide variety of allergenic plants. Although there is only limited knowledge of the extent of allergic disease from allergenic indoor plants, it seems logical to assume that if increased use is made of indoor plants that are pollen producers, atopic individuals may find indoor environments as unpleasant as the outdoors during the traditional pollen season. In addition, indoor blooming patterns are sometimes manipulated to be different from outdoor ''normal" seasonal patterns.
In addition to the plants themselves, plant materials such as Psyllium and latex can be brought indoors in a variety of consumer products. Psyllium is a grass from India used as a fiber and bulk supplement for bowel control. There are reported cases of severe anaphylactic reactions among workers who produce this product, as well as among those who use it. Airborne exposure to the product can also produce allergic reactions among susceptible individuals during use in the home.
Plant sources of allergens that have been shown to produce asthma in selected occupationally-exposed populations are presented in Chapter 2 (Table 2-4). Some of these plant materials can be present in residential and other indoor environments because of the activities of the occupants. Whether they will pose a hazard to the occupant depends on many factors including the amount of airborne exposures. Dried flowers are another example of a potentially allergenic product that can be brought indoors.
Latex allergy has recently received substantial attention because of increasing reports of its occurrence and its potential, in certain individuals, to produce life-threatening anaphylactic reactions. The latex (or sap) of the Havea brasiliensis plant is the source of natural rubber (cis-1,4-polyisoprene). Although rubber production yields a product that is 93–95 percent polyisoprene, the final product may be as much as 2–3 percent protein by weight (Windholz et al., 1983). The protein component of the latex contains allergens that are responsible for numerous recent reports of latex allergy. Exposure occurs by direct contact or by inhalation of dust or powder that is often used for packaging. Patient reactions to latex have ranged from contact urticaria to systemic anaphylaxis. Persons at increased risk include patients with congenital