What is it
It is a reaction of the immune system when it is exposed to usually harmless substances (pollen, mites, certain foods, drugs, etc.).
Food allergies should not be confused with intolerances, in which there is a negative reaction of the body, which however does not involve the immune system.
Usually you have the first symptoms of an allergy as a child, but in some cases they can also occur late.
Causes
Due to a genetic predisposition, the white blood cells of the immune system (leukocytes) that patrol the body to defend it from possible invasions by harmful substances and microganisms mistake for very dangerous some normally harmless substances (allergens).
Some white blood cells produce a large amount of particular antibodies (IgE, immunoglobulins E) which in turn lead to the release of substances (histamine, leukotrienes), which trigger the allergic reaction.
For example, in the case of respiratory allergies, exposure to pollen from some plants may trigger this abnormal reaction of the immune system.
Food allergies
Exposure to allergens in food triggers the abnormal reaction of the immune system just described. The most frequent food allergies in children are those to cow’s milk, egg, wheat, soy, etc. In addition to respiratory symptoms, food allergies (such as wheat allergy) can also cause itching all over the body. The diet must therefore be free of the “offending” foods.
Food allergies are often confused with food intolerances: these are reactions of the body to foods that it is unable to absorb or metabolize. A typical example is represented by lactose intolerance, which occurs in subjects who do not possess the enzyme capable of digesting this sugar. The main difference between allergy and intolerance concerns the absence, in the latter case, of an immune reaction. To counteract intolerances, it is recommended, as in the case of allergies, to eliminate foods at risk from the diet. If you suffer from lactose intolerance, for example, what to eat and what to avoid? In most cases it is not necessary to eliminate all dairy products: mature cheeses, which contain little lactose, are allowed, while milk (both cow’s milk and other animals), fresh cheeses and all milk-based products should not be taken.
We also often talk about yeast intolerance (although it is not actually a real intolerance) and gluten. In the latter case it is more correct to speak of celiac disease. The causes of celiac disease are to be found in an inflammatory state of the small intestine following the ingestion of foods containing gluten. But where is gluten found? To contain it are numerous cereals (such as wheat, spelt, barley, etc.) but also foods such as stock cubes, jams, ready-made sauces, etc. However, there are many gluten-free products on the market, which can be taken by celiacs traveling or away from home.
Celiac disease in children is frequently manifested by gastrointestinal disorders such as diarrhea, bloating and abdominal pain, while in adults the symptoms of celiac disease may be more nuanced.
Allergy to animal hair
To cause the allergy to the cat or dog is not actually the hair itself, but an allergen also present in the saliva, urine or sweat of the animal. Allergy sufferers who do not want to give up having a cat or a dog at home, can try to reduce exposure to allergens as much as possible by following some simple precautions, such as not letting the animal enter the bedroom, using vacuum cleaners and air purifiers with Hepa filters, etc.
Allergy to pollen and mites
Allergies can also be distinguished according to their duration: we speak of seasonal allergies when the allergen that causes them is present only at certain times of the year, and perennial allergies when exposure to the allergen can occur at any time. In the first case we generally speak of spring allergy, although there are summer or autumn ones, depending on the flowering period of the plant. For example, in case of allergy to pollen of parietaria, usually in the northern regions it is common to have allergy symptoms in June and August, when the concentration of pollen in the air is greater.
Pollen allergy is also commonly called “hay fever” as typical symptoms include stuffy and runny nose and repeated sneezing. On the contrary, the association between allergy and fever is quite rare.
A typical example of a perennial allergic form is instead the allergy to dust mites, small spider-like animals that nest in particular in pillows and mattresses.
Other allergies
In addition to food, animal hair, pollen and mites, there are also other allergic forms, such as:
In addition, we speak of cross-allergies when an allergen contained for example in the pollen of a plant is very similar to that present in a food. It is therefore possible that those who are allergic to grasses may also be allergic to tomatoes or kiwis.
Common symptoms
The symptoms can be localized in a specific area or systemic if they involve the whole organism.
The most frequently affected areas are:
Body area | Symptoms |
---|---|
Nose | Allergic rhinitis (swelling of the nasal mucous membranes, sneezing, colds) |
Airways | Difficulty breathing with bronchial spasm |
Eyes | Redness and itching of the conjunctiva |
Skin | Redness, itching |
The different forms of allergy can occur in one or more body districts. For example, in case of food allergies the symptoms can be both cutaneous and respiratory.
With regard to the skin in particular, an allergic skin reaction can cause spots on the face or hives, which is manifested by the appearance of small red spots on the skin, similar to bumps, which can also be associated with itching for example on the back or in other parts of the body.
If, on the other hand, the symptoms are mainly respiratory, it can range from a common allergic cold to episodes of asthma. But how do you recognize asthma? Dyspnea, dry cough, wheezing and tightness in the chest are the typical symptoms, which should not be underestimated.
When the reaction is systemic, it is called anaphylactic shock. It usually occurs very quickly (a few minutes) and is characterized by various symptoms, not all always present: agitation, palpitations, skin reactions, breathing difficulties due to edema of the glottis, bronchospasm and hypotension.
In severe cases it can lead to coma and death, and always requires prompt intervention.
Complications
The most serious possible complication in different allergies is anaphylactic shock. Other complications depend on the specific allergy you suffer, for example sinusitis in the case of allergic rhinitis.
In addition, for asthma sufferers, the flu and other respiratory infections should not be underestimated. Finally, it has been observed that celiac disease and diabetes can occur in the same individual with some frequency.
Treatment
It is a good idea to eliminate exposure to the allergen – avoiding for example foods or medications to which you are allergic.
If this is not possible, as in the case of allergy to dust mites, contact must be prevented as much as possible, for example by eliminating carpets and curtains, washing and dusting often the rooms in which you stay, ventilating the bedroom, and using anti-mite pillows and mattresses.
In case of symptoms of allergies such as seasonal hay fever, conjunctivitis or allergic rhinitis, the most used remedies are antihistamines. In some cases, however, the association between taking an antihistamine and drowsiness is possible.
Chromones also act on histamine, which prevent the release of white blood cells by the media.
However, they must be taken before contact with the substance that triggers the allergy, and therefore have a preventive function. The same applies to leukotriene inhibitors, which are used in allergic asthma.
In case of asthma, bronchodilator drugs can be used or, due to their effective anti-inflammatory action, some corticosteroids may be useful, preferably for local use so as to avoid the side effects associated with systemic use.
For allergies to inhaled substances (such as pollen and mites) there is also desensitization therapy (allergenic immunotherapy) which involves the subcutaneous injection of increasing doses of the allergen.
For the therapy of anaphylactic shock the life-saving drug is adrenaline.
Finally, in case of food allergies, it can be difficult to guarantee the body all the nutrients it needs. For this reason, for some forms of allergy, vitamin supplements can be useful to remedy their deficiency. In addition, some studies hypothesize that the increase in allergy cases in children is linked to changes in the intestinal flora. For this, it may be useful to take probiotics in children suffering from allergies and probiotics in pregnancy to reduce the likelihood of the unborn child to develop them during childhood.
When to consult your doctor
In the presence of allergy symptoms it is always good to consult a doctor because the lack or inadequate treatment can lead to a worsening of the situation.
Your doctor may prescribe some simple allergy tests to accurately define the type of allergy.
Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.
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