An allergy is our immune system’s way of responding in an exaggerated way to contact with certain external substances known as allergens.
Allergies are intensified in springtime, as one of the most common allergens to appear at this time of year is pollen, the reproductive cells found in the plants that proliferate in this particular season.
The allergic process
The immune system of allergy sufferers produces a type of antibody; a protein named Immunoglobulin E (IgE). The body produces a specific type of IgE for each allergen it responds to.
Immunoglobulin is the only antibody that binds itself to mast cells (cells that are found in tissue) and to basophils (a type of blood cell).
Both types of cells come into contact with the allergen, at which point the IgE that corresponds with that particular substance will attach itself and emit signals to instruct the inflammatory chemicals such as cytokines, histamines and leukotrienes to go into action.
These are the substances that provoke the inflammation in the respiratory system and cause the allergic symptoms.
What is rhinitis?
During Spring, Summer and Autumn, pollen floats about in the air. When we breathe, the pollen enters the nasal cavity and through contact, triggers allergic rhinitis.
Rhinitis is an allergic disorder that affects the nasal mucous membrane and causes sneezing – especially in the morning -, nasal and eye itching, nasal congestion, secretion and, in some cases, absence of the sense of smell.
Sometimes a post-nasal drip can occur, which can in turn produce a dry cough and congestive headaches.
Watery eyes and light sensitivity can also feature. Recurrent episodes of rhinitis should be evaluated by a specialist, who will take preventive measures against the possible onset of asthma or treat the asthma itself.
The problem is not just posed by seasonal rhinitis or hay fever – rhino conjunctivitis caused by an allergy to pollen at the end of spring and beginning of summer, can go from being episodic and occasional to becoming a recurring issue.
When the nasal mucous inflammation along with its associated symptoms is almost constant throughout the year, it is crucial to identify the trigger.
It is estimated that around 20% of the population is allergic to one substance or another (pollen, dust, food, fungus…) and this number appears to be rising.
This increase could be partially due to an improvement in health and hygiene standards in industrialised countries – children are less exposed to microorganisms such as viruses and bacteria.
This protection could mean that our under-worked immune systems are exceptionally stimulated as soon as they come into contact with an external substance such as pollen, which is usually harmless to our body.
Environmental pollution could also contribute to the rise of this disease, as it causes an inflammation of the nasal mucous membrane and optimises the absorption of pollen antigens.
This could explain why pollinosis is twice as common in urban areas as it is in rural areas, despite the greater exposure to pollen in these.
However, it is suspected that there is a hereditary predisposition to allergy, meaning that a child whose parents are allergic will probably develop some sort of sensitivity, although this would not always be caused by the same substance that his parents are sensitive to.
For example, if his mother is allergic to shellfish, he is more likely to develop an allergy that is not necessarily specific to that type of food – it may be to another allergen such as pollen.
When the body’s defences are lowered or weakened, i.e. after a viral infection or during pregnancy, it is much more susceptible to developing an allergy.
This illness tends to appear in childhood and adolescence. However, it is not unusual for it to develop at a later stage, when exposed to excessive pollution or pollen.
It is important to distinguish between seasonal and chronic rhinitis, as there are a few differences.
Grass, Parietaria judaica and the olive tree are common triggers of this affliction. Grass pollen is the main cause of hay fever, and in almost the rest of the world. In second place, olive pollen affects southern, central and eastern areas of the peninsula.
On the other hand, Parietaria judaica pollen only affects the Mediterranean coastal region.
Sometimes the cause is known and sometimes it is unknown. In perennial rhinitis where the cause is known, the catalysts are allergens (substances that have the potential to provoke allergy in certain people), whilst in perennial rhinitis where the cause is unknown or intrinsic, there needs to be an assessment of the patient’s particular sensitivities.
If we look at the allergens that bring about this type of rhinitis and become part of the day-to-day life of the patient, the most important of those are as follows: domestic dust mites (parasites that are smaller than the size of a pinhead and are found in huge numbers inside the mattresses and carpets of the home), saliva, epithelial tissue and urine belonging to pets (cats, dogs hamsters…) and some types of fungi.
Another trigger can be the work environment, where a type of rhinitis occurs, named occupational rhinitis.
The most commonly implicated elements in this environment are cereal flours, (bakery, ready-made food industry, animal feed factories…) proteolytic enzymes (factories handling detergents, medicines, flour…) and tropical timber.
Although these types of allergies are very bothersome, on the whole they are not serious issues – however, they can lead to more complex conditions such as asthma. In fact it is calculated that up to 8% of asthma sufferers have, to a greater or lesser degree, an allergic condition.
In these cases, the asthma appears as a result of inhaling allergens, and pollen is one of the main irritants.
Rhinitis or rhino conjunctivitis is not the same thing as asthma, but can suggest whether the patient is predisposed to develop the type of symptoms that are associated with bronchial hyper responsiveness (dry cough, breathlessness, wheezing etc.).
Nowadays we have a tendency to regard allergic rhinitis and asthma as being successive stages of the same respiratory disease.
If the cause of the disorder is clearly linked to a specific allergen, for example to dust mites, the treatment will primarily consist of avoiding future contact with it.
In the case of dust mites, for example, a good preventive measure is to place special mattress protectors, wash bed clothes at 60C or higher and remove carpets from the home.
However, it is not always possible to eliminate every risk factor; amongst other reasons, the sufferer may be allergic to several substances at the same time, some of which may not be easily controlled.
This is why, in the majority of cases and even more so when the cause of rhinitis is intrinsic or unknown, therapy should be supported by the use of medication. Of these medications, second generation antihistamines are widely used due to their non-sedative effects, and corticoids, when a lengthy treatment is necessary.
Always seek advice from your doctor, therapist, pharmacist or health professional.
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