Allergic rhinitis and antihistamine

What is allergic rhinitis and what are the effects of antihistamines in controlling it:

Allergic rhinitis is one of the most common medical disorders that affects four hundred million people worldwide.Allergic rhinitis may cause limitations in daily activities, decrease in quality of life and work, weakness, general fatigue, mental fatigue, confusion, decreased concentration, anxiety and inability to learn (due to lack of sleep and fatigue).

Types of rhinitis:

According to the pathogen, this disease can be divided into 3 categories: allergic rhinitis, non-allergic rhinitis and rhinitis caused by an underlying disease:

1. Allergic rhinitis: This type of rhinitis is caused by allergies and allergic reactions, which is divided into two types:
   1. Seasonal allergic rhinitis: This type of rhinitis mainly occurs in certain seasons of the year (especially spring and summer) or when exposed to stimulatory factors. The cause of occurrence is outdoor allergens such as pollen, grassy plants, trees, dust, etc. In this type, the duration of symptoms is short and is specific to a specific season or irritating conditions.
   2. Chronic allergic rhinitis: This type of rhinitis may continue throughout the year. It is caused by indoor allergens, such as mites (small creatures that live especially in carpets), fungi, molds and insects such as cockroaches. In this disease, the duration of symptoms is often long and may even be permanent.
2. Non-allergic rhinitis: In this case, allergic reactions are not the main cause of the disease, but some stimuli can cause rhinitis, such as smoking, pollution caused by petroleum compounds, eating spicy foods and cold and dry air.
3. 3- Rhinitis caused by an underlying disease: sometimes the symptoms of rhinitis such as nasal congestion and runny nose are caused by an underlying disease or drugs.

Ways to control rhinitis:

1. Non-drug treatments: environmental controls play an important role in preventing exposure to allergens.

2. Drug treatment: In many patients, in order to fully control allergic rhinitis, in addition to avoiding allergens, drug therapy should also be used. The choice of drug depends on the severity of the disease and is done according to the severity of the symptoms and the effect on daily activities. It can be single-drug, two-drug and even multi-drug.

Treatment options:

1. Antihistamines.
2. Nasal corticosteroids.
3. Cromolyn sodium.
4. Nasal inhalation decongestants.
5. Oral decongestants.
6. Ipratropium Bromide Nasal.
7. The first line of treatment for allergic rhinitis is based on symptom relief. In general, antihistamines and decongestants (oral and inhalation) are used at the beginning of drug treatment.

Antihistamines:

Considering the important role of histamine in the symptoms of rhinitis, drugs that inhibit this inflammatory mediator can play a very positive role in improving symptoms.Antihistamines are available in oral, ophthalmic and intranasal forms. Oral antihistamines are the most commonly used form and are divided into two categories: non-selective (first generation) and environmental selective (second generation).

First generation antihistamines:

These drugs cause side effects such as drowsiness and confusion and often have a short duration of effect and need to be prescribed several times a day, among which diphenhydramine, hydroxyzine and chlorpheniramine can be mentioned.

Second generation antihistamines:

These drugs do not cause drowsiness and also have a long duration of effect and are prescribed once or twice a day, which include loratadine, cetirizine and fexofenadine.These drugs are less effective than inhaled corticosteroids, but due to their limited side effects, convenient use and reasonable price, they are considered one of the important treatment choices.Antihistamines are most effective when taken approximately one to two hours before anticipated allergen exposure.

If you forget to take a dose, the next dose should not be doubled. Taking antihistamines with food or at least a full glass of water can help prevent digestive side effects. Another form of use is inhaled antihistamines, which are well accepted for seasonal allergic rhinitis, and in this regard, Azelastine antihistamine intranasal spray is available. Its 0.1% product can be used in children for seasonal allergies, while the 0.15% form is only used in adults for any type of allergic rhinitis. There is a possibility of side effects such as dryness, headache, drowsiness and decrease in effectiveness over time. Olopatadine is also an intranasal antihistamine and causes less drowsiness.