What is it?
An allergy is a situation in which the body presents an immune response (defense) different from the expected protective response, causing undesirable changes. The term “allergy” comes from the Greek “allos,” meaning original status changes. So, allergy is a specific reaction of the body's defense system to normally harmless substances. People who have allergies often are sensitive to more than one substance.
Types of allergens – substances that cause allergic reactions – include:
pollens powder particles fungal spores food latex insect venom drugs
When the allergy affects the respiratory system, called respiratory allergy.
How it develops?
We think today that allergic diseases, in general, have complex and multifactorial. It is believed that, for instance, there must be a combination of a person's genetic predisposition and environmental situation for facilitating the disease to externalize.
Among the factors that favor the development of allergic rhinitis in children, for example, we can mention passive smoking in the first year of life, history of allergies in first-degree relatives, exposure to allergens animals (cat dander, dog, etc.) and shortly breastfeeding among others.
Normally, the immune system functions as the body's defense against invading agents such as bacteria and viruses. However, most allergic reactions, immune system (defense) is responding to a false alarm. The person first comes into contact with an allergen and the immune system treats it as an invader and mobilizes to attack him.
The immune system generates large amounts of an antibody called immunoglobulin E (IgE).
Each IgE antibody is specific for a particular type of allergen.
In the case of pollen allergy, one type of antibody can be produced to react against one type of pollen, while another may be produced to combat other types of pollen.
When an allergen (pollen, dust or other) comes in contact with your specific IgE antibody, various chemicals are released into the blood and start to act in various parts of the body, as well as the respiratory system, causing allergy symptoms.
In the respiratory system, allergy can manifest as an allergic disease in the nose (allergic rhinitis) or in the lungs and airways (asthma or bronchial hyperreactivity).
There are also pollinosis (hay fever), a disease that occurs when the same time of year – spring, when pollination occurs. The pollen grains of plants are deposited in the nose and eyes, leading to an allergic reaction. Among the plants that cause allergies are: rye grass, cypress, eucalyptus, sycamores, acacia and others.
What do you feel?
sneezing coryza (runny nose) nasal obstruction cough post-nasal drip (“catarrh dripping behind the neck”) eyes, nose and throat slightly reddened wheezing
How is it diagnosed?
When the doctor talks with his patient, he has the ability to gather data that indicate the presence of disease.
The physical examination will help in this regard. In addition, the doctor may perform skin tests and blood tests as complementary.
In the skin test, the doctor can determine if the patient has on your skin type IgE antibodies that react to a particular allergen. Use of allergen extracts diluted as dust mites, pollens or molds in the test, which can be done by inserting the allergen under the skin or by application of scratch under a miniature done on the arm.
This skin test is easy to do, besides being cheap. However, it should not be done in those with eczema (type allergic disease disseminated skin). In such cases, it may be made a different diagnostic test called RAST, which uses a blood sample to determine the levels of circulating blood IgE antibody against a particular allergen.
Under medical supervision, some antidepressants and antihistamines should be discontinued before the diagnostic tests are performed, so the results are not affected. According to current medication, the suspension may be required up to 3 months in advance.
Regarding the interpretation of test results, we must remember that children and the elderly can be no underestimation of such results due to decreased reactivity in this group.
How is it prevented?
The doctor may recommend the use of anti-allergy to combat or prevent symptoms of respiratory allergies. Among these, we highlight corticosteroids and antihistamines. May be systemic use (that act on the whole body, such as injections, tablets and syrups) or localized action (creams, ointments, drops, sprays or inhalers). The best treatment option should be set by the doctor for the treatment and prevention of asthma, bronchial hyperresponsiveness and allergic rhinitis. Another option for treatment is immunotherapy (“vaccine”) injections with dosage which uses progressive substances that cause allergy, in order to “used” the body to receive such allergens, decreasing the sensitivity of the organism to these. Besides the medications, your doctor may advise the patient on how to avoid contact with allergens. Avoid mainly contact with strong odors, dust, fumes and do not stay in places that are being sanitized. Mattresses and pillows should be shielded or hypoallergenic materials should be used. Places with mold should be avoided and air conditioning filters should be cleaned weekly. Although there is no cure for allergies, one of these strategies or a combination of them can provide varying degrees of relief from allergy symptoms.
Questions you can ask your doctor
What can we do in the home environment to decrease the frequency of allergic events? What foods should be avoided to prevent allergies? Allergy medicines may cause drowsiness? May be used chronically anti-allergic?