What Is Allergic Rhinitis?
Allergic rhinitis, also known as hay fever, is an inflammation of the mucous membrane lining the inside of the nose, triggered by an exaggerated reaction of the immune system to environmental particles known as allergens.
The most common symptoms include repeated sneezing, nasal congestion, runny nose, and itching in the nose. These symptoms are often accompanied by watery eyes and eye itching, and can interfere with sleep, concentration, and overall quality of life.
It is estimated that up to 30% of adults and 40% of children will experience allergic rhinitis at some point in their lives. People with a history of asthma, atopic eczema (also known as atopic dermatitis), or other allergies are at even greater risk of developing the condition.
What Are Allergens?
Allergens are substances that can trigger an allergic reaction in sensitive individuals. For people without allergies, these particles are harmless; for those who are allergic, they “trick” the immune system, which begins to treat them as dangerous invaders.
Allergens can come into contact with the body in several ways:
- Inhalation: pollen, household dust, dust mites, animal dander, smoke, mold, volatile chemicals
- Ingestion: foods (such as milk, eggs, shellfish, peanuts), medications, supplements
- Skin contact: latex, perfumes, creams, plants, metals (like nickel), cleaning products
- Skin inoculation: insect stings or bites, such as from bees and mosquitoes
Important: It’s not the direct action of the allergen that causes symptoms, but the exaggerated response of the immune system. That’s why the same substance can be completely harmless to some people and trigger severe reactions in others.
How Allergic Rhinitis Develops
Hay fever develops when a genetically predisposed person comes into contact with an allergen through the nose.
At the first exposure — usually in childhood — the allergic person’s body mistakenly identifies the substance as a dangerous invader. This leads to the production of allergen-specific IgE antibodies, as if the body were preparing to fight off a virus or bacteria.
These IgE antibodies attach to the surface of immune cells called mast cells, located in the nasal mucosa. You can think of mast cells as “armed sentinels,” ready to react at the slightest sign of the allergen.
At the next exposure to the same substance, the allergen binds to the IgE antibodies on the surface of the mast cells. This triggers the activation of these cells, which release a series of inflammatory substances — the most important of which is histamine.
Histamine causes:
- Dilation of blood vessels, leading to nasal congestion
- Stimulation of nerve endings, resulting in itching
- Increased mucus production, causing a runny nose
- Sneezing, as a reflex to try to expel the allergen
In addition to histamine, other inflammatory mediators such as leukotrienes and prostaglandins, as well as immune cells like eosinophils, help sustain the inflammation and prolong the symptoms.
In summary, the symptoms of allergic rhinitis are a side effect of an exaggerated defense reaction. The allergen itself isn’t harmful — but the allergic person’s immune system reacts as if it were.
Risk Factors
Allergic rhinitis is more likely to occur in people with a genetic predisposition and a personal or family history of other allergic conditions, such as asthma, atopic dermatitis (eczema), and allergic conjunctivitis.
Several factors increase the chances of developing hay fever:
- Male sex: especially in childhood, when the prevalence is higher among boys.
- Family history of respiratory or skin allergies
- Being born during times of high pollen concentration, such as spring or early summer, depending on the region
- Early interruption of breastfeeding: breast milk supports the maturation of the immune system and may reduce the risk of allergies
- Exposure to cigarette smoke during the first year of life
- Frequent use of antibiotics in childhood, which can alter the microbiota and influence the immune system
- Living in environments rich in allergens, such as places with a lot of dust, mold, carpets, heavy curtains, and pets
The earlier and more intense the exposure to allergens, the greater the likelihood that the immune system will overreact — leading to sensitization and recurrent allergy flare-ups.
Symptoms of Allergic Rhinitis
Allergic rhinitis can cause mild, moderate, or severe symptoms, and its impact goes far beyond nasal discomfort — it can interfere with sleep, concentration, and performance at school or work.
Most common symptoms of hay fever:
- Repeated sneezing, often in the morning
- Runny nose (clear, watery nasal discharge)
- Nasal congestion (stuffy nose)
- Itching in the nose, eyes, throat, or roof of the mouth
- Watery eyes and eye irritation
- Dry cough caused by postnasal drip
- Reduced sense of smell and taste
In some cases, there may be facial pain or pressure, especially if sinus inflammation (rhinosinusitis) is also present.
Characteristic clinical signs of allergic rhinitis:
- Dennie-Morgan lines: folds or creases under the lower eyelids
- Allergic shiners: dark circles under the eyes caused by congestion of local blood vessels
- “Allergic salute” sign: a repetitive gesture of rubbing or lifting the tip of the nose with the hand to relieve itching and ease breathing
Patterns of allergic rhinitis:
- Seasonal: flare-ups that occur during specific times of the year, usually related to increased pollen in the air
- Perennial: symptoms present year-round, more common in people continuously exposed to household allergens such as dust mites, mold, or animal dander
When a patient remains exposed to allergens, flare-ups tend to become more frequent and intense, and the amount of allergen needed to trigger symptoms gradually decreases. In advanced stages of sensitization, even non-allergic factors — such as sudden temperature changes, smoke, strong odors, or cold air — can trigger symptoms.
Diagnosis and Tests
In most cases, the diagnosis of allergic rhinitis is based on medical history and physical examination, without the need for complex tests. The doctor evaluates the symptoms, their pattern of occurrence, and possible triggering factors.
Key elements of the clinical assessment:
- History of symptoms: onset, duration, frequency, and seasonality
- Situations that worsen or improve symptoms: exposure to dust, animals, mold, weather changes, etc.
- Family history of allergic diseases
- Presence of other allergic conditions: asthma, atopic dermatitis, allergic conjunctivitis
- Findings on physical examination: pale or bluish nasal mucosa, watery nasal discharge, typical signs such as allergic shiners and Dennie-Morgan lines
Complementary Tests
These are not always necessary, but they can be helpful in doubtful cases or when it is important to identify the specific allergen.
- Skin prick test: small drops of common allergen extracts are applied to the skin, usually on the forearm or back. A local reaction (redness and swelling) indicates sensitivity to that substance.
- Specific IgE blood test: measures the amount of IgE antibodies directed against specific allergens. Useful when skin testing is not possible, such as in patients with extensive skin disease or those on continuous antihistamine use.
- Imaging tests (rarely required): CT scan or X-ray of the paranasal sinuses may be requested if complications, such as chronic sinusitis, are suspected.
Differential Diagnosis
It is important to distinguish hay fever from other conditions with similar symptoms, such as:
- Viral rhinitis (common cold)
- Non-allergic rhinitis (irritative or vasomotor)
- Sinusitis
- Deviated nasal septum
- Nasal polyps
Treatment
The treatment of allergic rhinitis has two main goals: to control symptoms and to reduce exposure to the allergens that trigger flare-ups. Whenever possible, identifying the specific allergen is essential, since simple preventive measures can reduce the need for medications.
In some cases, environmental control alone is enough to keep the condition under control, while in others it may be necessary to add medications or even immunotherapy.
Nasal Saline Irrigation
Rinsing the nasal passages with saline solution (isotonic or hypertonic) helps remove allergens and secretions, reducing local inflammation. It can be done daily, even outside of flare-ups, and also before applying other medications such as corticosteroid or antihistamine sprays. It is a safe method with no contraindications for long-term use.
Antihistamines
Histamine is the main chemical mediator released by mast cells during an allergic reaction. Antihistamines block its action on H₁ receptors, relieving sneezing, runny nose, and itching. They can be taken orally or applied topically (nasal spray).
They are divided into two categories:
- First-generation (e.g., diphenhydramine, chlorpheniramine, dexchlorpheniramine): effective, but cause drowsiness and reduced alertness because they cross the blood-brain barrier. Best suited for nighttime use or short-term flare-ups.
- Second-generation (e.g., loratadine, desloratadine, cetirizine, levocetirizine, fexofenadine, bilastine): cause less sedation and are more appropriate for continuous use.
Azelastine nasal spray is a topical antihistamine applied directly to the nostrils. It blocks H₁ receptors in the nasal mucosa, providing quick relief — usually within about 15 minutes — from symptoms such as runny nose, sneezing, and itching. It can be used during acute flare-ups or continuously. Because it acts locally, the risk of drowsiness or systemic effects is low.
There are also combination formulations of azelastine with a nasal corticosteroid (such as fluticasone). This pairing combines the rapid relief of an antihistamine with the anti-inflammatory control of a corticosteroid and is recommended for moderate to severe cases that do not respond well to a single medication.
Important: antihistamines alone have limited effect on nasal congestion, so they are often combined with nasal corticosteroids.
Nasal Corticosteroids
Topical nasal corticosteroids are considered the first-line treatment for moderate to severe allergic rhinitis, according to major international guidelines. They reduce inflammation and improve all key symptoms — including nasal congestion, which responds poorly to antihistamines.
Common options include: fluticasone, mometasone, budesonide, flunisolide, triamcinolone, and beclomethasone. All are similarly effective when used correctly.
- The effect is not immediate: it may take a few days to reach maximum benefit. For severe flare-ups with intense congestion, the doctor may prescribe a short course of a nasal decongestant or an antihistamine before starting the corticosteroid.
- They are safe for long-term use in adults and children, provided the prescribed dose is followed.
- For prolonged treatment, follow-up with an ENT specialist is recommended to check the nasal cavity and prevent rare complications such as mucosal injury or infections. In children, growth should be monitored.
Nasal Decongestants
Sprays containing substances like oxymetazoline or oral solutions with pseudoephedrine constrict the blood vessels in the nasal mucosa, rapidly reducing swelling and mucus production.
While they provide quick relief, their use should not exceed three consecutive days, since they can cause rebound congestion — the nose becomes blocked again, and the patient may become dependent on the medication to breathe properly. This condition, called rhinitis medicamentosa, is difficult to reverse.
For this reason, decongestants should be used only occasionally and under medical supervision.
Leukotriene Receptor Antagonists
Medications such as montelukast block the action of leukotrienes, inflammatory substances released during allergic reactions. They are less effective than nasal corticosteroids and are not usually the first-choice treatment, but they may be useful in patients who also have asthma or cannot tolerate other therapies.
Immunotherapy (Allergy Shots or Tablets)
Specific immunotherapy aims to desensitize the body, reducing its reaction to allergens. It can be administered subcutaneously (injections) or sublingually (drops or tablets dissolved under the tongue).
The treatment involves gradually increasing doses of the allergen until a maintenance dose is reached. The goal is to “train” the immune system to tolerate the substance, decreasing the frequency and intensity of flare-ups.
- Immunotherapy is recommended only when allergens are clearly identified (such as pollen, dust mites, or animal dander).
- Treatment usually lasts three to five years and should not be stopped early, otherwise its effectiveness may be lost.
Prevention and Environmental Control
Avoiding or reducing exposure to allergens is an essential part of managing allergic rhinitis, especially when the triggers have already been identified. These measures help decrease the frequency and intensity of flare-ups and, in some cases, may reduce the need for medication.
The recommendations vary depending on the type of allergen involved:
Dust Mites
- Wash bedding weekly in hot water (above 55 °C / 130 °F)
- Use dust-mite-proof covers on pillows and mattresses
- Remove rugs, heavy curtains, and stuffed animals from the bedroom whenever possible
- Keep the house well ventilated and avoid excessive humidity
- Vacuum with a HEPA-filter vacuum cleaner
Pollen
- Keep windows closed on days with high pollen counts
- Avoid outdoor activities early in the morning and on dry, windy days
- Shower and change clothes after returning from outside to remove pollen from skin and hair
Pets
- Keep pets out of the bedroom
- Bathe them weekly if possible
- Avoid direct contact with their fur during peak allergy periods
Mold
- Eliminate sources of water leaks and dampness
- Use dehumidifiers in closed and humid environments
- Clean walls and surfaces with appropriate antifungal products
Non-allergic Irritants
Even though they are not allergens, substances such as cigarette smoke, strong perfumes, cleaning sprays, and air pollution can worsen allergic rhinitis.
- Completely avoid exposure to cigarette smoke, especially in children
- Reduce the use of strong-smelling products at home
In addition, keeping good nasal hygiene through regular saline irrigation helps remove allergens and irritating particles, working both as prevention and as part of treatment.
Frequently Asked Question (FAQ)
Does allergic rhinitis cause hoarseness?
Not usually. What can happen is that a patient with allergic rhinitis also develops allergic laryngitis. Allergic laryngitis occurs when exposure to allergens such as pollen, dust mites, animal dander, or other irritants causes inflammation of the larynx (voice box), leading to typical laryngitis symptoms such as hoarseness, loss of voice, throat pain, or irritation.
Some respiratory viral infections can cause both rhinitis and hoarseness. In this case, however, the cause of both is infectious — not allergic.
What is the best antihistamine for allergic rhinitis?
There isn’t a single antihistamine that stands out above all others. If you want an antihistamine that causes drowsiness and helps with sleep at night, first-generation antihistamines, such as hydroxyzine and dexchlorpheniramine, are good options. If you prefer one that causes little to no drowsiness, second-generation antihistamines, such as desloratadine and fexofenadine, are better choices.
Does hay fever cause fever?
Allergic rhinitis usually does not cause fever. If a person with rhinitis develops a fever, it is more likely due to another condition occurring at the same time, such as a respiratory infection (for example, bacterial sinusitis, the common cold, or the flu). In these cases, the fever is not caused by rhinitis itself, but by the associated infection.
Is irritative rhinitis the same as allergic rhinitis?
No. Irritative rhinitis and allergic rhinitis are two different types of inflammation of the nasal mucosa. Irritative rhinitis occurs in response to irritants that are not related to immune reactions. These irritants may include environmental pollutants, cigarette smoke, chemicals, sudden temperature changes, strong odors, or even dry air. Unlike allergic rhinitis, it does not involve the production of IgE antibodies or the release of histamine.
What is the difference between rhinitis and sinusitis?
Rhinitis and sinusitis are distinct conditions, although both affect the upper respiratory system.
Rhinitis is inflammation of the nasal mucosa, with symptoms such as runny nose, sneezing, nasal congestion, and itching.
Sinusitis is inflammation of the paranasal sinuses, usually caused by infections. Symptoms include facial pain, sinus pressure, nasal congestion, thick nasal discharge, and sometimes fever.
In summary: rhinitis affects the nose, while sinusitis affects the sinuses.
How long does an allergic rhinitis flare-up last?
The duration of an allergic rhinitis flare-up can vary depending on exposure to the allergen and the severity of the reaction. In general, a flare-up may last from a few hours to several days.
Acute flare-up: when a person is exposed to a specific allergen (such as pollen or dust), symptoms may last for a few hours or days, as long as the exposure stops.
Perennial allergic rhinitis: in cases of continuous exposure to allergens (such as dust mites or animal dander), symptoms can persist for longer periods, with recurrent flare-ups lasting weeks or even months, depending on environmental control and treatment.
With proper treatment (antihistamines, nasal corticosteroids), the duration of flare-ups can be reduced.
What is the best nasal spray for allergic rhinitis?
For long-term and effective control, nasal corticosteroids (such as budesonide, fluticasone, mometasone, and triamcinolone) are considered the first choice.
Azelastine nasal spray is a good alternative for quick relief and can be used alone or in combination with a corticosteroid.
There are also formulations that combine azelastine + fluticasone, providing both immediate action and long-lasting anti-inflammatory effects.
References
- International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis – International Forum of Allergy & Rhinology.
- Allergic Rhinitis – American College of Allergy, Asthma & Immunology.
- Treatment of Allergic Rhinitis – American Family Physician.
- An overview of rhinitis – UpToDate.
- Allergic rhinitis: Clinical manifestations, epidemiology, and diagnosis – UpToDate.
- Pharmacotherapy of allergic rhinitis – UpToDate.
- Allergic Rhinitis – Medscape.
