Write any two physical features of the part of the flower that causes allergic reactions.
Answers
Answer:
.Pollen is one of the most common triggers of seasonal allergies. Many people know pollen allergy as “hay fever.” Experts usually refer to pollen allergy as “seasonal allergic rhinitis.”
Each spring, summer and fall, plants release tiny pollen grains to fertilize other plants of the same species. Most of the pollens that cause allergic reactions come from trees, weeds and grasses. These plants make small, light and dry pollen grains that travel by the wind.
Grasses are the most common cause of allergy. Ragweed is a main cause of weed allergies. Other common sources of weed pollen include sagebrush, pigweed, lamb’s quarters and tumbleweed. Certain species of trees, including birch, cedar and oak, also produce highly allergenic pollen.
Plants fertilized by insects, like roses and some flowering trees, like cherry and pear trees, usually do not cause allergic rhinitis.
Answer:
THERE IS MORE BUT IT CANNOT FIT
Explanation:
Occupational and recreational plant exposure on the skin is fairly common. Plant products and extracts are commonly used and found extensively in the environment. Adverse reactions to plants and their products are also fairly common. However, making the diagnosis of contact dermatitis from plants and plant extracts is not always simple and straightforward. Phytodermatitis refers to inflammation of the skin caused by a plant. The clinical patterns may be allergic phytodermatitis, photophytodermatitis, irritant contact dermatitis, pharmacological injury, and mechanical injury. In this article, we will focus mainly on allergy contact dermatitis from plants or allergic phytodermatitis occurring in Asia.
Keywords: Phytodermatitis, phytophotodermatitis, plant dermatitis
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Introduction
Clinical features
Once an individual is sensitized to a plant allergen, subsequent contact will elicit acute cutaneous lesions within 12-48 hours. The reaction is an acute eczema with severe pruritus, oedema, erythematous papules and urticarial-looking plaques that rapidly become studded with vesicles and tense bullae. Skin lesions appear where the plant has brushed against the skin, typically on the legs, thighs, hands and upper limbs. They classically display a linear morphology of crisscrossing streaks. The sticky sap can be transferred from the fingers to more distant sites, such as the face, trunk, and genitals. New lesions tend to continue to erupt for 1-2 weeks and may last for 4-8 weeks, or to flare up after stopping short courses of systemic corticosteroids. In subsequent episodes, the skin eruptions tend to become more severe, and they tend to appear after a shorter interval following exposure to the plant.
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Plants that Cause Allergic Phytodermatitis in Asia
Allergic phytodermatitis
Several families in the plant kingdom are notorious causes of allergic phytodermatitis. Of particular importance are the Anacardiaceae (i.e., the cashew or sumac family) and Compositae (also known as the Asteraceae, including the aster, daisy or sunflower family). Different types of allergic phytodermatitis exist in different regions of the world.
The Anacardiaceae family
Plants such as the poison ivy, poison oak and poison sumac is a common cause of allergic phytodermatitis in North America. When damaged, all parts of the plant exude a sticky, strongly allergenic oleoresin, called urushiol. The allergens are pentadecylcatechols or heptadecylcatechols which possess benzene rings that bear hydroxyl groups at position 1 and 2, and aliphatic side chains at position 3. The length of the side chain and the number of its double bonds determine the allergenicity of the molecule.
In Asia, the Anacardeaceae family includes the mangoes fruit tree (Mangifera indica), lacquer tree (Toxicodendron vernicifluum) and hardwood (Gluta renghas) are the commonest causes of allergic phytodermatitis. The mango fruits contain urushiol in their exocarp (outer skin). Facial and perioral dermatitis occurs when a sensitized individual bites into an unpeeled mango. Approximately 80% of Japanese cabinetmakers exposed to the varnish extracted from the lacquer tree develop hand and forearm dermatitis. The cashew nut tree, Anacardium occidentale, bears reddish fruits that contain the kidney-shaped nut within a three-layered pericarp. The middle layer is filled with brownish oil rich in cardol and anacardic acid, chemically similar to urushiol. These catechols are destroyed when the nut is properly roasted and processed, but harvesters can develop allergic phytodermatitis from exposure to the oil.
Although unrelated to the Anacardiaceae, the Ginkgo biloba tree, which is found in temperate Asian countries, is also a source of urushiol-like catechols. The allergenic ginkgolic acid is present exclusively in the flesh of the drupe-like ovule