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Most humans mount significant Immunoglobulin E (IgE) responses only as a defense against parasitic infections. However, some individuals mount an IgE response against common environmental antigens. This hereditory predisposition is called atopy. In atopic individuals, non-parasitic antigens stimulate inappropriate IgE production, leading to type I hypersensitivity. Sensitivities vary from one person to another and it is possible to be allergic to an extraordinary range of substances.
Types of allergies
Dust mite excretion, pollen and pet dander are all common allergens, but it is possible to be allergic to anything from chlorine to perfume. Food allergies are not as common as food sensitivity, but some foods such as peanuts (a legume), nuts, seafood and shellfish are the cause of serious allergies in many people.
Officially, the Food and Drug Administration does recognize 8 foods as being common for allergic reactions in a large segment of the sensitive population, which includes, peanuts, tree nuts, eggs, milk, shellfish, fish, wheat and their derivatives, soy and their derivatives, and sulphites (chemical based, often found in flavors and colors in foods) at 10ppm and over. See the FDA website for complete details. It should be noted that other countries, due to differences in the genetic profiles of its citizens and different levels of exposure to different foods, the "official" allergen list will change. Canada recognizes all eight of the allergens recognized by the US, and also recognizes sesame seeds.
Another type of allergen is urushiol, a resin produced by poison ivy and poison oak. It causes the skin rash condition known as urushiol-induced contact dermatitis by changing a skin cell's configuration so that it is no longer recognized by the immune system as part of the body. A little over half of North Americans are known to be allergic to urushiol and repeated exposure can increase one's sensitivity to the allergen.
An allergic reaction can be caused by any form of direct contact with the allergen—consuming food or drink one is sensitive to (ingestion), breathing in pollen, perfume or pet dander (inhalation), or brushing a body part against an allergy-causing plant (direct contact, generally resulting in hives). Other common causes of serious allergy are wasp, fire ant and bee stings, penicillin, and latex. An extremely serious form of an allergic reaction is called anaphylaxis. One form of treatment is the administration of sterile epinephrine to the person experiencing anaphylaxis, which suppresses the body's overreaction to the allergen, and allows for the patient to be transported to a medical facility.
In 1952 basidiospores were described as being possible airborne allergens and were linked to asthma in 1969. Basidiospore are the dominant airbourne fungal allergens. Fungal allergy is associated with seasonal asthma. They are considered to be a major source of airbourne allergens. The basidospore family include, mushrooms, rusts, smuts, brackets, and puffballs. The airbourne spores from mushrooms reach levels comparable to those of mold and pollens. The levels of mushroom respiratory allergy are as high as 30 percent of those with allergic disorder, but it is believed to be less than 1 percent of food allergies. Heavy rainfall (which increases fungal spore release) is associated with increased hospital admissions of children with asthma. A study in New Zealand found that 22 percent of patients with respiratory allergic disorders tested positive for basidiospores allergies. Mushroom spore allergies can cause either immediate allergic symptomatology or delayed allergic reactions. Those with asthma are more likely to have immediate allergic reactions and those with allergic rhinitis are more likely to have delayed allergic responses. A study found that 27 percent of patients were allergic to basidiomycete mycelia extracts and 32 percent were allergic to basidiospore extracts, thus demonstrating the high incidence of fungal sensitisation in individuals with suspected allergies. It has been found that of basidiomycete cap, mycelia, and spore extracts that spore extracts are the most reliable extract for diagnosing basidiomycete allergy.
In canada 8 percent of children attending allergy clinics were found to be allergic to Ganoderma which is a basidiospore. Pleurotus ostreatus, cladosporium, and calvatia cyathiformis are significant airbourne spores. Other significant fungal allergens include aspergillus and alternaria-penicillin families. In India fomes pectinatis is a predominant air bourne allergen effecting up to 22 percent of patients with respiratory allergies. Some fungal air-bourne allergens such as coprinus comatus are associated with worsening of eczematous skin lesions. Children who are born during autumn months (during fungal spore season) are more likely to develop asthmatic symptoms later in life.
- Animal products
- Insect stings
- Mold spores
- Plant pollens (hay fever)
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