A pesky world. Allergy, hypersensitivity or intolerance?

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“I am allergic” – this sentence is heard so often that you may wonder if allergy is just fashionable. It is interesting how many true allergy sufferers are among us, and how many attribute this disease to themselves without being confirmed by tests.

The term “allergy” appeared in medical terminology as early as 1906. It comes from Greek and literally means: a different reaction than usual (Greek allos ergos). When this definition was created, the state of medical knowledge about the mechanisms governing immunity was significantly different from the present one, therefore the current understanding of allergy also differs from the original concept.

From aversion to hypersensitivity

In the XNUMXst century, people talk not only about allergies, but also about hypersensitivity, intolerance and aversion, and each of these terms means something different. In addition, lest it be so obvious, it should be noted that the colloquial understanding of these words differs significantly from their medical meaning. Therefore, it is worth checking what the differences between them are based on the example of the easiest to analyze varieties related to the digestive system.

• Food aversion is a psychological reaction triggered by the recognition of the appearance, smell or taste of a food. It does not exist if the product is in a masked form.

• Food intolerance is an abnormal, but not immune, reaction of the body caused by a food, without any psychological factor involved. It may be due to an enzyme deficiency, a pharmacological effect, or an unknown cause (then referred to as idiopathic intolerance).

• A food allergy is an unwanted immune response caused by a food.

• Hypersensitivity is again the body’s reaction to a certain type of factor, such as a food ingredient, more intensely than usual.

So we can see that aversion is always psychological, intolerance is a non-immune reaction, hypersensitivity in turn determines the degree of the reaction, not its mechanism, and allergy is always related to some dysfunction of the immune system.

As you can see, there are differences, so they should be taken into account, and unfortunately all these terms are used almost synonymously in everyday language.

Precise classification

For the needs of the topic of the month discussed in our topic, the above definitions are sufficient, but for the sake of accuracy it is worth mentioning the precise distinction between hypersensitivity and allergy in scientific medical terminology, included in the so-called Coombs classification.

According to this scale, created on the basis of biochemical mechanisms taking place in tissues and cells of the reaction, five types of hypersensitivity were identified, of which only two are classified as allergies. Therefore, allergic diseases will be those in which antigens react with IgE antibodies, such as urticaria, allergic asthma, allergic rhinitis and conjunctivitis, food allergies, and finally atopic dermatitis and eczema.

However, diseases with an allergic origin include those that do not have any word associated with allergy in their name. Examples include: sarcoidosis, Crohn’s disease, granulomatous hypersensitivity, contact eczema. But in these diseases there are cellular reactions involving T lymphocytes, which also determines their allergic origin.

From the point of view of medical terminology, belonging to an allergy is determined not so much by a symptom as by the mechanism of the development of the disease and the body’s reaction. Hypersensitivity is therefore a broader concept than allergy, hence every allergy is hypersensitivity, but not all hypersensitivity is an allergy.

The case is unequal

If we have already managed to reach this place together and we have gone through the meanders of medical terminology and details of the formation of allergic reactions, it will be easy to continue. We will try to use the example of fragments of letters from readers to analyze together when we can actually deal with an allergy, and when it is only hypersensitivity or intolerance, and what should we do if we notice the same symptoms.

Of course, it should be said at the outset that without examinations and a visit to a doctor, even on the basis of the most accurate description of the disease or well-being, it is impossible to diagnose an allergy with 100% certainty. So if we notice symptoms similar to those found by Mrs. Agnieszka, do not diagnose ourselves and do not give up examinations and visiting a specialist.

Agnieszka wrote that no one in her family suffered from allergies, so she did not expect her symptoms to be related to this disease. Is this thinking correct? Yes, but only partially, because we do not inherit allergies, but a tendency to it, but at the same time we must remember that allergic diseases are now increasingly common in people who are not burdened with families, for which scientists blame contamination of the environment with pollutants, an increased amount of preservatives in food and many other factors. So we cannot assume in advance that such a problem will never happen to us.

Agnieszka noticed that she never had a fever, even when she was ill. This fact may indicate both the weak immunity of the body (which does not react by increasing the temperature during an infection), and may be one of the symptoms of an allergy that arises, especially when it is accompanied by a cough and runny nose that do not go away after a week of treatment, as with any ordinary infection . When observing the symptoms of your disease, you should pay attention not only to their type, but also to their repeatability and variability over time.

Coughing fits, especially in winter when entering the office, is a symptom of the so-called bronchial hyperresponsiveness, which may or may not be an allergy. There is a group of patients whose bronchial tubes contract when the temperature of the air inhaled suddenly changes, but they still do not have bronchial asthma. On the other hand, bronchial hyperreactivity is also one of the factors accompanying asthma, which is why Agnieszka should perform a spirometric test consisting in measuring the volume and velocity of air flow through the lungs and bronchi during inhalation and exhalation, which is done by blowing into a special device connected to the computer called a spirometer.

Are salvos of sneezing after leaving the pool also an allergy or just hypersensitivity? Also, this question cannot be answered unequivocally, because some people have a more sensitive nasal mucosa than others, and if they choke on chlorinated water, they will sneeze as if after taking snuff, which does not mean that they must be allergic. In this case, however, you should pay attention to the frequency of such seizures – whether they occur every time (we can suspect an allergy), or they occur sporadically after pouring water into the nose.

Do more tests

In order to make a diagnosis, it is helpful to perform allergic skin tests, which can be: prick tests, intradermal or epidermal patch tests (APT). In prick tests, the allergen is applied as drops of solution to the skin of the forearm (10-12 allergens for each hand), while in the more sensitive intradermal test, it is injected with a syringe under the skin in an amount of 0,03-0,05 ml of the solution, creating a vesicle of 3-4 mm in diameter. In the case of epidermal (patch) tests, the allergens are applied to special patches and stuck to the test person on the back or on the shoulders for a period of 24-72 hours. The occurring allergic reactions are manifested in the form of redness, vesicles and nodules. It is assumed that a positive point test confirms an allergy, while a negative intradermal test allows to exclude it, therefore a diagnosis is never made on the basis of one test only. If an allergic reaction to chlorine or other chemicals (latex, solvents, detergents) is suspected, epidermal patch tests are usually performed.

In making a proper diagnosis, it is also helpful to perform a serological blood test, especially to quantify the total content of IgE (in allergy sufferers its level usually exceeds the upper limit), or to determine the level of a specific antibody specific for a given allergen. Clinical practice shows that the more tests performed, the better, because there are patients whose skin tests do not show allergies and can be confirmed after serological tests.

The case of Agnieszka, or inhalation allergy

“When I was a little girl, I often developed long-term infections and inflammation of the respiratory tract. Currently, I am less sick, but if something catches me, I never actually have a fever. However, I have noticed that I have had weird bouts of coughing, especially when I walk into my office in the morning. Winter was the worst. Sometimes, when I stand near an open window at work, I also have bouts of sneezing. Now, for a good welcome to spring, I started going to the swimming pool with my daughter and I noticed that when we got home I couldn’t help sneezing for a few minutes. A colleague from work says that I probably have an allergy, but in my family no one has ever had such diseases. Should I see a doctor? “

Agnieszka

Inhalation allergy

The bouts of sneezing about which Agnieszka complains may be a symptom of inhalation allergy, especially when it occurs during the pollen season. These types of allergies occur when the allergen enters the body through inhalation. They can even be life-threatening, especially when they are accompanied by severe local swelling of the larynx or bronchospasm (risk of suffocation) or when a generalized reaction of the body appears (anaphylactic shock), which may occur within a few to several minutes after contact with the allergen. For this reason, any suspected allergy should be diagnosed to detect a potential source of allergy or to establish further treatment options.

An interesting fact is that a desensitized patient may still react very strongly to the antigen in skin tests (their result does not change), but he tolerates contact with the allergen very well in normal life (e.g. being among the plants that are the source of the allergen during the pollen season).

Since medicine is said to be an art, there must be exceptions to any rule. Therefore, there are patients who, despite the detection of a specific allergen in skin tests, are unable to produce a specific antibody for it in the blood, and therefore it is not possible to undergo specific immunotherapy.

Short medical course

The most common mechanism of allergy development

Let us assume that during a spring walk we enter a cloud of plant pollen invisible to the naked eye, which then gets into the body through the nose, where it acts like a blanket on our B lymphocytes, forcing them to produce an antibody, i.e. immunoglobulin E (IgE). B lymphocytes are one type of white blood cell, or leukocyte, present in everyone’s blood. The antibody (IgE) produced in this way travels on to cells called mast cells or mast cells. They occur in mucous membranes, where after the attachment of immunoglobulin E to the receptor on the surface of the mast cell, the first imperceptible stage of allergy development ends. At this point, we don’t have any symptoms yet, and we don’t know we’re allergic to anything. However, if we come across pollen again, it will be quickly captured this time by immunoglobulins attached to the surface of the mast cell. This is when the second stage of the allergic process begins, called mast cell degranulation, when the mast cell suddenly spills out. Cell organelles of the mast cell fall out, containing a large amount of an irritating substance – called histamine, which, when released to the outside, attaches to the histamine H1 receptors in the blood vessels, causing these vessels to widen and increase their permeability. It is then that the symptoms of allergies that are visible to us develop: swelling and swelling, bronchospasm, drop in blood pressure, discharge from the nose, itchy skin, rash or even diarrhea.

The case of Teresa, or food intolerance

“I’ve never been able to eat onions and it didn’t surprise anyone at home anymore, especially since I’ve had my own bread knife for years, so that someone wouldn’t smear a slice of butter with the aroma of onions on me. However, I do not remember that until I reached the age of majority, I could not drink milk, which I have never liked, but when the sheepskin was removed, I was even able to drink it. Recently, however, after drinking milk, I have had strange splashes and stomach pains, and sometimes even diarrhea. My husband says I’m probably allergic to cow’s milk, and a nurse friend says she’s lactose intolerant. So am I burdened with an allergy or should I just not drink milk and then I don’t have to be treated? “

Teresa

Ms Teresa’s problem is related to the often asked by patients the question of distinguishing between allergies, aversion and food intolerance. If we find similar or the same symptoms, we probably also ask ourselves whether stomach pain is sometimes a symptom of normal dietary errors and the resulting indigestion, or simply the result of nervous eating under stress and in a hurry. Such reasons are also possible, but in the case of Teresa it seems to be something else. While the reluctance to eat onions having a psychological background is food aversion, the symptoms of discomfort and stomach pain after milk consumption, appearing regardless of the psychological factor, will be food intolerance.

Since problems only arise after drinking milk, testing for lactose intolerance, which is a deficiency of the lactase enzyme that breaks down milk sugar lactose, causes lactose to ferment in the intestine, retain water, and form watery diarrhea. Despite the fact that these symptoms are very similar to the symptoms of food allergy, allergic reactions are not involved in their formation. Primary lactose intolerance in adults, also called adult hypolactasia, is a genetically determined disease, and therefore hereditary. It should not be confused with clinical manifestation of lactose intolerance. Usually, patients with hypolactasia can consume small amounts of milk – the tolerance limit is 200-300 ml of milk per day.

In the case of an adult, however, the second type of lactose intolerance, called secondary or acquired, should also be considered, which is both not hereditary and not an allergic reaction, but occurs as a result of damage to the mucosa of the small intestine, most often due to excessive use of antibiotics or non-steroidal anti-inflammatory drugs (NSAIDs). However, lactose intolerance may also appear as an additional symptom accompanying serious diseases, such as, for example, Zollinger-Ellison syndrome or Crohn’s disease, therefore Ms Teresa’s condition requires diagnostic tests.

So what should be done? You can have the concentration of galactose and glucose in the blood and urine measured, because both of these simple sugars are formed by the breakdown of lactose by lactase. Another good solution is to test the presence of hydrogen in the exhaled air, as this gas is produced by anaerobic (in the case of lactase deficiency) lactose fermentation.

The burden of food allergy

After all these treatments, however, there is one more possibility that Teresa’s husband spoke about, i.e. a typical milk allergy.

How is it different from lactose intolerance? First of all, milk allergy has the usual mechanism of formation, based on the reaction of an allergen (e.g. cow’s milk beta-lactoglobulin) with IgE, which can be detected by skin prick tests, as is the case with other allergens. Allergies to various types of milk (cow, soy), however, are the most common nightmare of children in infancy, so adults who drank milk without any problems in childhood should rather be tested for lactose intolerance.

Food allergies often last a lifetime, so people suffering from them must completely eliminate the ingredients that contain the allergen. Food products with the strongest allergenic effects include peanuts, chocolate, citrus fruits, tomatoes, blue cheese and various types of milk, including soy.

The common point in the treatment of food intolerances and allergies is to eliminate the component causing both of these conditions from the diet. In the case of Teresa, as in most people with lactose intolerance, it is enough to put away the dishes containing sweet milk and replace them with sour milk or fermented by yoghurt or kefir bacteria. Then, most likely, these products will no longer cause symptoms of intolerance.

Pseudoallergy to preservatives

When writing about aversion, allergy and food intolerance, one should also mention an additional type of pseudoallergic reaction, which symptomatically closely resembles an allergy. However, it is not of any known type, nor can it be classified as food intolerances. So what is the reason and cause of its occurrence?

It was noted that out of 1,5 thousand substances added to food as flavor and aroma improvers, preservatives and dyes, some chemical compounds after ingestion with food cause reactions resembling allergy symptoms, but their mechanism of action does not detect antigen-antibody reactions or genetically determined deficiency of metabolic enzymes.

A typical example is monosodium glutamate (E-621) used as a flavor enhancer in soups. However, this compound causes a pseudoallergic reaction in susceptible individuals called “Chinese restaurant syndrome”. After its consumption, symptoms such as nausea, drooling, sweating and itching of the skin, recurrent swelling of the skin and mucous membranes, and even attacks of shortness of breath occur.

The case of Zofia, i.e. allergic dermatitis

“I use a variety of liquids to wash the dishes, but they make my skin dry, so I have to use moisturizing creams. To protect my hands, I started wearing rubber gloves before washing the dishes, but the skin on my hands is cracking and drying out, or I get weird bubbles that disappear after a few days. Recently, I noticed that some buttons and bracelets that come into direct contact with my skin also cause redness and itchy lesions on my skin. “

Zofia

Ms Zofia’s dilemma is, in fact, not distinguishing between common non-allergic skin irritation and allergies. Unfortunately, also this time without visiting a dermatologist and conducting tests, it is impossible to make a correct diagnosis with complete certainty.

Symptoms of non-allergic contact eczema (exudative papules and vesicles, often accompanied by itching), resulting from skin contact with detergents and detergents, are almost identical to the changes that appear on the skin in allergic contact dermatitis, also known as allergic contact eczema. However, they differ in the mechanism of their formation.

In contact allergic eczema, Coombs’ type IV hypersensitivity reaction, involves Th1 lymphocytes, Langerhans cells, and special molecules called haptens, while non-allergic eczema only releases protein particles (cytokines) from epidermal cells called keratinocytes. So if we find any contact changes on our skin, as long as they do not disappear spontaneously within a few days, it is better to always show them to a dermatologist.

To differentiate the type of eczema, your doctor may order an epidermal test, which consists of applying patches with allergens to the skin and reading the skin lesions after 24 to 72 hours. In the case of contact allergic inflammation, the test results will be positive.

Allergic contact

The most common triggers of contact allergic dermatitis are substances containing chromium (matches, paints and dyes, cement), cobalt (ornaments, jewelry pieces, buttons) and some chemicals added to cosmetics. In the case of Mrs. Zofia, regarding skin changes as a result of abrasion by a button or bracelet, one should rather expect an allergic basis.

However, when analyzing the drying of the skin due to the use of dishwashing liquids, we can talk about local non-allergic irritation rather than atopic dermatitis. Atopic dermatitis is also a symptom of dry skin, but it is always allergic, and skin lesions in sick people occur not only on the surface of the hands, but also in many characteristic places of the body. In this disease there is an excessive production of IgE antibodies, which is not observed in the usual contact drying of the skin with detergent.

The formation of strange bubbles on the skin of the hands after using disposable dishwashing gloves is also a symptom of latex allergy, which is the main component of both rubber gloves used at home and those worn at the operating table.

From the pharmacy shelf

It is better not to leave a true allergy diagnosed and confirmed by tests alone. A real allergy must be treated, not only when it threatens us with anaphylactic shock, after a bee sting, which is trivial for an ordinary mortal. Untreated asthma reduces the vital signs of the lungs, causing shortness of breath and coughing attacks, even with normal daily activities such as walking upstairs in a block of flats or cycling, which can become unfeasible for asthmatics in advanced disease. Most often, we go to the pharmacy for first aid. Some preparations are available without a prescription, others can only be prescribed by a doctor.

They eliminate the symptoms

The most frequently selected preparations are those from the group of antihistamines that prevent the released histamine from binding to the receptor and triggering an allergic reaction. They do not cure the cause, but they effectively eliminate bothersome symptoms, such as: sneezing, runny nose or swollen mucous membranes. But antihistamines do not stop a real asthma attack with symptoms of shortness of breath and persistent cough, so they are allowed to be sold by hand only in the lighter forms of allergy and hypersensitivity.

Without a prescription, we can buy antihistaminics containing 7 or 10 tablets of cetirizine (Aleras 10 tablets, Amertil 7 or 10 tablets, Reactine 7 tablets, Zyrtec 7 tablets, Letizen 7 tablets) or loratadine (Loratan 7 or 10 tablets, Lorivax 10 tablets, Aleric 7 tablets) However, the doctor prescribes larger packages (more than 20 tablets).

Desensitization or vaccines

If we are allergic to pollen of plants or animal venoms, a more effective solution will be to carry out desensitization by a doctor, i.e. specific immunotherapy. It is a treatment that works directly on the cause of the allergy, not on symptoms.

There are many vaccines available in the pharmacy (Phostal, Pollinex, Allergovit, Catalet, Novo-Helisan, Staloral), but these are always preparations prescribed only by a medical prescription.

Aerosol or drops

If our allergic problems are only local, we can use an aerosol or eye drops instead of tablets, depending on whether our eyes are watering or runny nose.

Without a prescription, we can buy nasal Cromohexal, Polcrom or Cropoz N, which contain cromic acid or its salt – sodium cromoglycate. They block the release of histamine from mast cells (degranulation), which inhibits the formation of an allergic reaction.

Intranasally, we can also use Betadrin WZF drops, which contain two active ingredients: diphenhydramine hydrochloride (antihistamine) and naphazoline nitrate decongesting the blood vessels of the nasal mucosa. It is currently the only over-the-counter nasal preparation that contains diphenhydramine.

The chemical equivalents of these preparations with sodium cromoglycate – in allergic conjunctivitis – are drugs in the form of eye drops, e.g. Vividrin, Allergocrom and Allergo-Comod, Polcrom or Lecrolym. We also buy these preparations without a prescription.

They will relieve itching

If our problems with allergies or hypersensitivity occur in the form of inflammations and contact eczema with itchy skin, we can help ourselves by buying a 0,5% hydrocortisone cream (Hydrocort, Iwostin HC).

Fenistil gel, known from the holiday anti-mosquito ads, will also prove to be useful, the active compound of which – dimetindene, belonging to the group of antihistamines – also has antipruritic and anti-inflammatory properties.

For inhalation allergies and asthmatic attacks

In life-threatening allergies due to rapidly progressive swelling or shortness of breath, it is necessary to resort to medications prescribed only by a doctor after thorough diagnostic tests. In recent years, in inhalation allergies and asthmatic attacks, glucocorticosteroids (hormones) and bronchodilators acting on beta-2 receptors are the most commonly used. In practice, they replaced preparations from other chemical groups.

Despite assurances from manufacturers that in doses allowed for use in inhalations, glucocorticosteroids are not absorbed into the general circulation, we must remember, however, that they are highly potent hormones that have a lot of side effects (e.g. hair loss). In the case of using steroids, the body also tends to get used to the dose used, which unfortunately has to be increased over time, and this intensifies the side effects.

The most common preparations in this group are drugs containing the following hormones: fluticasone (Flixotide, Flixonase), beclometasone (Beclazone), and budesonide (Pulmicort, Miflonide, Budesonide, Budenofalk, Neplit Easyhaler).

The combinations of these hormones with beta-2-adrenergics are the following preparations: fluticasone + salmeterol (Saltikan, Seretide Disk), beclometasone + formoterol (Formodual, Fostex), budesonide + formoterol (Symbicort Turbuhaler).

Drugs containing beta-2-adrenergic alone are: fenoterol (Berotec N), formoterol (Oxis Turbuhaler, Foradil, Zafiron, Diffumax Easyhaler), salmeterol (Serevent Disk, Pulmoterol), salbutamol (Buventol Easyhaler, Ventolin Disk).

Your doctor may also prescribe a medicine containing montelukast or zafirlukast, substances with a strong anti-inflammatory effect that inhibits smooth muscle spasms in the respiratory system. Preparations from this group are: montelukast (Singulair, Montest, Montelukast, Lukast, Asmenol, Drimon), zafirlukast (Accolate).

It is worth mentioning ipratropium bromide – a drug from the group of cholinolytics that acts as a bronchodilator in asthmatics. Its prescription preparations are: Atrovent, Steri-Neb Ipratropium or in combination with fenoterol (Berodual).

Due to side effects and termination of registration, the xanthine derivatives used in asthma, such as aminophylline, theobromine and papaverine (Aminophyllinum, Eucardin, Theopaverin), have become obsolete.

Text: Rafał Jabłoński, MA in pharmacy

Source: Let’s live longer