Causes and Symptoms of Allergy
It is very important to distinguish between the causes of allergy and its triggers. The cause of all allergies is hypersensitivity of some individuals to certain substances which are known as the allergens and trigger an excessive reaction to a substance which in similar amount has no effect on other people. The triggers or allergens greatly vary from person to person, while different types of allergies result different symptoms.
Different types of allergies and hypersensitivity of some individuals to certain substances greatly depend from several factors which can be divided into host and environmental factors. If one will be affected by allergy greatly depends on gender, race, age and heredity but also from the environmental impacts. It turned out that people in urban areas are more frequently affected by allergies that the rural population although the differences between rural and urban population is slowly disappearing due the pollution of countryside with pesticides, insecticides, artificial fertilizers, etc. Scientists also assume that besides pollution allergies are in some cases also a result of too sterile homes what prevents contact with sufficient amount of pathogens in the early childhood resulting oversensitivity in later period of life. A human body normally deals with certain level of pathogens all the time but if living in too sterile environment in the early childhood one's immune system will likely attack harmless antigens such as dust and animal hair. However, according to the newest researches changed structure of conventionally cultivated foods has also great impact on rising number of people suffering from various types of allergy. Besides treatment with pesticides, insecticides, antibiotics, artificial fertilizers, etc. while growing the majority of foods are added or treated with preservatives before ending on our plates, while their structure is often additionally alternated with heating in the microwaves, etc. Potential risk factor for allergies and perhaps also for other diseases also represent genetically modified organisms impact of which will be known few years or decades later.
If the allergy-causing substance are airborne particles such as dust or pollen the symptoms usually occur in areas which are in direct contact with the air: nose, lungs and eyes causing symptoms of asthma attacks, hay fever, sneezing, coughing, itching and/or redness of the eyes, but can also affect the skin causing rashes. Allergies which affect the skin are widely known as dermatitis and cause inflammation, itching, swelling, rashes, hives and eczema. Besides respiratory system and skin the allergens can also affect gastrointestinal system causing nausea, vomiting, diarrhea and abdominal pain, while certain drugs and insect stings often affect multiple organ systems including digestive system, respiratory system and circulatory system causing violent reactions which can be in worst case even fatal.