What are allergies - how they are diagnosed and treated?

What is allergy?

Allergy is a chronic disease caused by an inadequate, unwanted, and unexpected response of the immunity substances that usually do not lead to any illness and do not harm humans, for example, food, medicines, pollen, insect poison, etc.

An allergic response to these substances occurs when various tissues of the body are exposed to them. Usually, they cause the manifestation of allergic symptoms namely in these tissues. For example, skin, in the gastrointestinal tract, in the respiratory tract, etc.

Allergic reaction

The immunity is our organism’s defense system the main purpose of which is to fight against such external aggressors as bacteria, viruses, fungi, and other pathogens.

The immune system of people suffering from allergies sees an aggressor (allergen) in a foreign substance and begins to fight it by producing a specific antibody called the type E immunoglobulin. These antibodies activate various cells of the immunity, mainly mast cells, and induce them to secrete various substances, i.e. histamine, leukotrienes, and others that cause the symptoms of allergy, i.e. runny nose, rash, indigestion, and so on.
Antibodies of type E are unique for various specific allergens, and therefore some people, for example, may suffer from an allergic response to olive pollen, while others only to cat hair, nuts, etc.

An allergic response can provoke various symptoms. For instance, breathing in of substances that a person is allergic to cause a runny nose, itching of the nose and throat, sneezing, tears, involvement of the lower respiratory tract will cause an asthma attack, skin involvement is manifested in rashes and itching, the involvement of the digestive system causes pain in the abdomen, indigestion, and involvement of the heart and blood vessels leads to anaphylactic shock – the most dangerous type of reaction that can be fatal if no adequate help is received within minutes.

Prevalence of allergies

Although there are many types of allergic reactions, some allergies are more common than others. The most widespread manifestation allergic rhinitis then comes asthma, atopic dermatitis, and allergic sensitivity to food, medicines, and insect bites.

About 25-40% of people around the world suffer from some kind of allergic disease, and this number has been growing steadily over the past decades.

Types of allergic diseases

- Allergic rhinitis. This disease is manifested by frequent sneezing, runny or clogged nose, itching in the pharyngeal cavity, and also frequent itching and redness of the eyes.
Multi-season allergic rhinitis (which can occur in any season) is usually caused by allergens in the home, such as house dust mites (in this case, the allergy develops to a protein secreted by the mites), mold spores, or allergens secreted by the saliva or mammary glands of cats and dogs.
The most common type is seasonal sensitivity to pollen from various plants. The symptoms only occur during the flowering seasons of these plants. Seasonal allergies, sometimes called hay fever, usually occur in spring (when olive trees and pecans are in bloom) or fall (when other plants are in season).
- Allergic inflammation of the eyes.This type of allergy manifests itself in tearfulness, redness, and itching of the eyes or eyelids, and it often accompanies allergic rhinitis. The most common cause for symptoms occurrence is also pollen from various plants and mites in house dust.
- Allergic (bronchial) asthma.
Asthma manifestations (troubled breathing, coughing, and suffocation) develop due to inflammation of the airways. The inflamed airways swell and become narrower resulting in suffocation. Nearly 70% of patients with asthma suffer from this type of disease and half of them also suffer from allergic rhinitis. In kids, this type of asthma is more frequent than in adults.
- Atopic dermatitis (atopic eczema). This condition is also called skin asthma. We are talking about skin inflammation, which usually has a recurrent course. It is distinguished by itching, dry skin, and a red rash. Sometimes, the spots are also covered in dandruff or rough skin. This condition is more frequent in infants and young children. A typical rash appears in various parts of the body based on the age of the sick person: in kids and teens, it usually affects elbows and under the knee area, and in adults - the palms, neck, etc. In individuals will this type of allergy, the likelihood of food sensitivities, rhinitis, and asthma is increased.
- Urticaria (hives). A is a type of allergic reaction distinguished by an itchy rash and red spots with a raised, edematous center that appears in various parts of the body. This rash is very itchy, but usually goes away on its own within a few hours after onset, and then appears and disappears elsewhere. At the same time, its color does not change and it does not leave scars on the skin. In addition to the rash, nearly 42% of patients will have subcutaneous swelling (angioedema), usually on the lips, hands, eyelids, etc. Urticaria can manifest itself in an acute form (it does not go away for a long time: from several hours and days, and up to six weeks). In these cases, a systemic/skin reaction may occur.

The chronic type of the disease does not go away for more than a month and a half, or even longer, and in severe cases, it may not go away for many months or years. However, chronic disease is usually not an allergic reaction but an immunological response due to unknown reasons.

- Allergy to food. This type of allergy is distinguished by a rapid allergic manifestation that can often be life-threatening (anaphylaxis) to various foods. In most cases, people are allergic to milk, eggs, fish, crustaceans, shellfish (Molluscs), different kinds of nuts, certain seeds, or grains. The percentage of people with food allergies is constantly growing worldwide, and it is supposed that 3-5% of kids under 6 years old and 1-2% of schoolchildren have at least one food allergy. Some of them will also suffer from food allergies in adulthood. The life-threatening complications develop even after consuming a minimum amount of a certain food so it is important to have an emergency medication that must be administered immediately (Epinephrine autoinjector best known as EpiPen).
- Allergy to medicines. Side effects of medicines including allergic reactions are one of the main causes of morbidity and mortality in Western countries because medicines can cause anaphylaxis, and repeated exposure to this medicine (and sometimes another medicine of the same type or group) can be life lethal. For people with known allergies, it is highly advised to do an allergy test before using any new medication. On the other hand, it is very common to misdiagnose allergies, and so many patients are not given proper treatment. The use of alternative drugs due to suspicion of an allergy to the desired medicine may result in the patient being forced to take a less effective and more expensive drug. Therefore, accurate diagnosis of medication allergy is vital. It should also be noted that in special cases, it is possible to allow the intake of an essential medicine (for example, chemotherapy in the case of cancer or therapy with antibiotics for which there is no substitute), even if the patient is sensitive to these medicines. This requires a procedure by an allergist called desensitization.
- Other forms of allergy. There are other forms of allergy widespread around the world, such as bee venom allergy. For this life-threatening allergy, there is treatment through allergy vaccination (immunotherapy), which protects 99% against the anaphylactic reaction caused by repeated bites.

Another type of allergy that significantly worsens the quality of life of sick people is allergic skin inflammation as a result of contact with an allergen. This is an itchy skin infection accompanied by an eczema rash that appears after prolonged skin contact with a foreign substance (for example, nickel, cosmetics, rubber, gloves, etc.). To allow the skin to heal and prevent exacerbations, it is important to find out the allergen experimentally, i.e. stop wearing certain fabrics or metals as jewelry, etc. and see how your skin reacts.

How is diagnostics of allergies made?

Allergies are diagnosed by doctors - clinical allergists and immunologists who specialize in the treatment of various diseases of the immune system.

The allergy diagnosis process includes:

- Obtaining detailed information about the symptoms experienced by the person who applied;
- Examination of the patient;
- Skin reaction tests or blood tests to check for allergies to find out which substance is causing the allergy;
- In some cases, specific provocative tests are required to confirm or exclude suspicion of allergy. It is a diagnostic procedure during which the patient is exposed to a substance to which he may be allergic. This can be life-threatening, and thus is carried out gradually under medical supervision in allergy clinics, whose employees are able to conduct these tests and treat possible reactions.

Allergy therapy

After identifying the allergy factors, it is possible to choose the right individual treatment for each patient.

Allergy treatment includes:

- Instructions to prevent further contact with the allergen;
- Drug treatment: drug therapy is offered if needed (only when symptoms appear) or on a regular basis (in severe cases and based on the appointment of an allergist);
- In addition to medication to alleviate the symptoms of the disease, biological and chemical forms of therapy are now used. They render an impact on the immune system and stop the incorrect response leading to disease.
- Immunotherapy - treatment with allergy vaccinations (used only for allergic rhinitis, asthma, sensitivity to bee stings), which can lower allergic sensitivity.

Correct diagnosis and therapy of allergies can significantly improve the quality of life of patients and even lead to recovery. Thus, if you suspect that you have allergy, you should not postpone a visit to a therapist or allergist and do all prescribed tests.

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Post by: Natalie Keller, M.D. General Health Centre, Minneapolis, Minnesota