What is it?
The concept of allergy was first introduced by two Viennese paediatricians Piquet and Schick, the first to observe how an alteration of the immune system could trigger abnormal responses in humans.
An allergy is an exaggerated immune reaction to substances that are normally harmless, such as dust, pollen, mites, chemicals, drugs, animal hair and foods.
Immune tolerance refers to unresponsiveness of the immune system toward certain substances or tissues that are normally capable of stimulating an immune response. As a consequence there can be atypical responses of organs and systems such as respiratory, digestive and skin.
Types of allergies
As previously mentioned, allergies can involve different systems or organs and present with different levels of severity.
The most common allergies are rhinitis, asthma, allergies from insect or animal bites, contact, drugs and food.
Depending on the case, the symptoms can be mild or severe. The most serious reactions are chronic asthma, chronic dermatitis and anaphylactic shock.
Mechanism of action
The immune system cells, whose function is to attack pathogens such as viruses or bacteria.
When a harmless substance is encountered by a person who is allergic to that substance, the cells of the immune system such as basophils and mast cells may over react by producing antibodies that “attack” the allergenIn case of an allergy, the immune system overreacts to an allergen by producing antibodies called Immunoglobulin E (IgE). These antibodies travel to cells that release chemicals, causing an allergic reaction. This reaction usually causes symptoms in the various organs or tissues such as skin, nose, eyes and intestines.
Symptoms associated with allergies are very heterogeneous and depend on the target tissues or organs:
- If the nasopharynx is involved, we speak of rhinitis, the symptoms of which include colds, sneezing and intense mucus secretion;
- If the eyes are involved, symptoms such as redness, intense tearing and redness of the eyes occur;
- If the lungs are involved, asthma develops. Asthma is a condition in which your airways narrow and swell and may produce extra mucus. This can make breathing difficult ;
- If the skin is involved, symptoms such as hives, edema, redness, burning, chronic dermatitis, blistering, flaking and crusting occur.
- If the intestine is involved, there are symptoms such as itching and redness of the oral cavity, hives, skin edema, vomiting, diarrhea, nausea, general itching. In severe cases, anaphylactic shock can occur.
In addition to visual observation of the symptoms, there are various tests that can help diagnose an allergy:
- Blood analysis with IgE dosage;
- An allergen challenge test involves directly exposing you to a substance to try to find out whether you are allergic to it. In the event of an allergy, the patient will experience skin, nasal, respiratory or gastrointestinal symptoms, depending on the type of allergen tested.
- Patch tests can detect delayed allergic reactions, which can take several days to develop. Patch tests don’t use needles. Instead, allergens are applied to patches, which are then placed on your skin, usually in the forearm, abdomen and back. A positive patch test will be red, raised, and itchy possibly lasting several weeks;
- The skin prick test is similar to the patch test. The difference is that the allergen is used directly in contact with the skin.
- A radioallergosorbent test (RAST) is a blood test using radioimmunoassay test to detect specific IgE antibodies in order to determine the substances a subject is allergic to. In practice, the IgE present in the blood are marked with radioactive, so that following the contact reaction with the allergen, the IgE-allergen complex will emit a radioactivity. The amount of radioactivity is proportional to the serum IgE for the allergen.
The first rule to follow is to absolutely avoid contact with the specific allergen. Of course, this is easier to achieve with allergens such as drugs or foods, while it is more complicated for environmental allergens such as mold, pollen, dust, mites or animal hair.
In most cases, therapy is mainly pharmacological, in order to have a ready-to-use response, given the rapid manifestation of symptomatic responses.
- Pharmacological as antihistamines to inhibit the release of histamine, cortisones with immunosuppressive action, bronchodilators that fight the restriction of the respiratory tract typical of asthmatic subjects, leukotriene antagonists that inhibit the release of leukotrienes, or mediators of inflammatory responses, stabilizers of macrophages, which block the release of histamine from them.
- The drugs used are different eye drops, in case of swelling and redness in the mucous membranes of the eye. Very often they have active ingredients such as mast cell stabilizers or antihistamines. Nasal spray to fight allergy rhinitis, frequent dripping caused by specific allergens (allergic cold), have active ingredients such as antihistamines or corticosteroids. Tablets or drops with active ingredients such as antihistamines, corticosteroids and leukotriene antagonists, for allergic rhinitis, skin allergies, mucous membranes of the eyes or respiratory tract.
- Specific immunotherapy is a therapy whose main objective is to accustom the body to the specific allergen, trying to establish an immunological tolerance with the consequent reduction of allergic reactions. In addition, the approach involves the administration, for 2-5 years, of the allergen in increasingly higher doses, subcutaneously or by means of sublingual tablets or drops.
There are a number of guidelines to follow for a stable and strong immune system:
- It is very important to maintain the insulin function in homeostasis and therefore the blood sugar level. It is necessary to favor foods with a low glycemic index, cereals, bread, pasta that are not refined and not manipulated, but wholemeal and completely excluding sweets and processed products.
- Histamine is a molecule that significantly activates the reactivity of the immune system. Avoid high-content foods such as canned fish such as tuna, mackerel, eggplant, peppers, spinach, mushrooms and dark chocolate.
- It is important to keep the stress hormone scientifically known as cortisol low, with food its levels are kept low by avoiding excessive consumption of coffee, non-whole grains and avoiding too drastic diets.
- It is important to keep the intake of omega 3 and omega 6 constant in the weekly cycle, therefore favor the consumption of dried fruit such as walnuts, almonds, oily fish such as sea bass, sole, anchovies and mackerel.
To mitigate the inflammatory states of the immune system, it is important to follow an antioxidant diet, integrating foods such as seasonal fruit and vegetables, spices and herbs grown in pots or dried.