The range of possible allergies is huge - whether pollen, grasses, pet hair, food, cosmetics, medicines or fragrances: When the immune system attacks these actually harmless environmental substances, there can be many complaints: The eyes burn, the nose runs and itches, Allergy sufferers even have breathing problems. To alleviate the symptoms of an allergy, it is often only a relief and a change in behavior. However, in certain allergies, hyposensitization can also relieve the symptoms.
Expiration of an allergic reaction
If the immune system overreacts in contact with normally harmless substances, by viewing them as enemies and then forms antibodies, the next contact with this substance will lead to an allergic reaction. Antibodies such as immunoglobulin E ensure that the body's own immune cells release aggressive inflammatory substances. Histamine and other messengers then cause swelling, itching and dilated blood vessels. This reaction may be local or affecting the whole body, depending on whether the nose, skin, bronchi or circulatory system are affected.
In addition to the reaction via antibodies, which often occurs just minutes after contact with the "hostile" substance (the allergen), the immune system also has the ability to allow certain cells (T cells) to react to substances - this leads to contact allergies. Here, the reaction often occurs only after hours or days.
Causes of an allergy
Why the immune system suddenly has an allergic reaction is still unknown. Allergies are increasing worldwide - it is speculated whether in addition to hereditary influences, the increasing pollution or the inadequate germ contact in childhood are responsible. In total, more than 20, 000 allergens are known: they can be inhaled, taken with food or as a medicine and have contact with them through the skin - even involuntarily as in a wasp sting.
Distinguished from the allergic reaction is the pseudoallergy, which shows similar symptoms as an allergy, but already occurs at the first contact with a substance - without the body forms antibodies. Thus people react against salicylates (also against ASA) often pseudoallergic. In cross-allergic reactions, on the other hand, the body responds to substances that are somewhat similar to the substance on which it has formed antibodies - so people with a birch pollen allergy often respond to apples or nuts.
Typical symptoms of allergies
An allergy can be associated with a variety of symptoms: swelling, itching and dilated blood vessels cause the eyes to redness and conjunctivitis. It can cause colds and a swollen nasal mucous membrane that obstructs breathing. When the lungs react with it, asthma develops: in the tense, swollen bronchi, tough mucus forms, which is difficult to cough up. Added to this is the typical, grunting-sounding asthma breathing sound.
The skin of allergy sufferers itches and tenses frequently, it is also dry and red: In the area of these eczema, the appearance of the skin changes from soft to coarse (especially strong in atopic dermatitis). In addition, digestive problems with diarrhea, flatulence, constipation or bloating in the area of the gastrointestinal tract are possible. In addition, the dilation of the blood vessels can lead to serious circulatory problems - when the blood with a running throughout the body quasi "sagging", it comes to cardiovascular failure. This life-threatening situation is called anaphylactic shock, it often occurs in insect venom allergies or after intravenous administration of certain drugs.
Anamnesis (ask for medical history): All complaints can be further limited by specific questions - nevertheless, allergy diagnostics often remain detective work. Thus, a nose stuffed every morning may indicate a house dust allergy and pets can be held responsible for so many allergies.
In various skin tests a variety of substances are tested - redness, itching and swelling indicate that the immune system really responds to the substance. Unfortunately, the skin tests are not always reliable.
Blood test: The concentration of immunoglobulin E in the blood indicates whether allergy is present (RIST test), the more expensive RAST test confirms an allergy to a certain substance, if the skin test was previously noticeable. In a provocation test, the person concerned is deliberately confronted with the potentially allergenic substance - because of the risk of a severe reaction (the anaphylactic shock) is performed only rarely and under medical supervision.