Allergic Rhinitis

What it is

Allergic rhinitis is an IgE-mediated nasal allergy that affects about 1 in 6 people and causes sneezing, congestion, itching, and a runny nose. It happens when the immune system overreacts to inhaled allergens such as pollen, house dust mites, animal dander, or molds. Common symptoms are nasal blockage, clear watery discharge, repeated sneezing, postnasal drip, and itching of the nose, eyes, or throat. Unlike a common cold, allergic rhinitis is not caused by a virus and does not usually cause fever.

It may be seasonal when symptoms flare during pollen seasons, perennial when symptoms occur year-round from indoor triggers, or mixed. StatPearls notes that roughly 20% of cases are seasonal, 40% perennial, and 40% have features of both. Allergic rhinitis often occurs alongside asthma, eczema, or allergic conjunctivitis because these conditions share an atopic, or allergy-prone, immune pattern. In India, common triggers can include dust exposure, house dust mites, seasonal pollens, mold in damp indoor spaces, and air pollution that can worsen symptoms even if it is not the original allergen.

Pattern	Typical triggers	Symptom timing
Seasonal	Tree, grass, or weed pollens; outdoor molds	Certain months or weather periods
Perennial	Dust mites, pet dander, cockroaches, indoor molds	Throughout the year
Mixed	Indoor plus outdoor allergens	Year-round with seasonal worsening

How it works

Allergic rhinitis is driven by a type 2 immune response. After a person becomes sensitized to an allergen, the body makes allergen-specific IgE antibodies. These IgE antibodies attach to mast cells in the nasal lining. On re-exposure, the allergen binds to IgE and triggers mast-cell degranulation within minutes, releasing histamine and other mediators.

This early phase causes sneezing, itching, and watery discharge. A later inflammatory phase follows, involving leukotrienes, cytokines, and eosinophils, which contributes more to persistent congestion and nasal swelling. This is why some people feel blocked up for hours after exposure even after the initial sneezing settles.

The condition is part of the broader "unified airway" concept. The nose, sinuses, and lungs are linked, so inflammation in the upper airway can coexist with or worsen lower-airway disease such as asthma. Poorly controlled allergic rhinitis can also disturb sleep, concentration, school performance, and work productivity.

Diagnosis / how it's measured

Diagnosis is usually clinical, based on the pattern of symptoms and trigger history. A clinician may ask whether symptoms occur after dust exposure, around pets, during pollen seasons, or in certain rooms. Physical findings can include pale or swollen nasal mucosa, clear secretions, mouth breathing, or dark under-eye circles sometimes called allergic shiners.

Tests are not always needed, but they can help when the diagnosis is uncertain or when immunotherapy is being considered.

1. History and exam: Most important first step.
2. Skin-prick testing: Identifies sensitization to specific allergens.
3. Serum specific IgE blood tests: Useful when skin testing is not practical.
4. Nasal endoscopy or imaging: Considered if another problem is suspected, such as polyps or chronic sinusitis.

A key point is that a positive allergy test alone does not prove the cause of symptoms. The test result has to match the history. Conditions that can look similar include viral colds, non-allergic rhinitis, sinusitis, medication-related rhinitis, structural nasal blockage, and in children, enlarged adenoids.

Evidence and uses

Treatment aims to reduce exposure to triggers, control inflammation, and improve quality of life. The best-supported first-line medicines for most people with bothersome symptoms are intranasal corticosteroid sprays. These work better than oral antihistamines for nasal congestion and overall symptom control when used correctly and regularly.

Common treatment options include:

Treatment	Main role	Notes
Intranasal corticosteroids	Best overall symptom control	First-line for persistent or moderate symptoms
Oral or intranasal antihistamines	Sneezing, itching, runny nose	Less effective for congestion than nasal steroids
Saline nasal irrigation	Symptom relief, mucus clearance	Helpful add-on, low risk
Leukotriene receptor antagonists	Selected patients, especially with asthma	Not first-line for most people
Allergen immunotherapy	Long-term disease modification	Consider when symptoms persist and trigger is confirmed

Allergen avoidance can help, but complete avoidance is often difficult. Dust-mite measures may include washing bedding regularly, reducing indoor dampness, and limiting dust reservoirs. During high-pollen periods, keeping windows closed at certain times and showering after outdoor exposure may reduce symptoms.

For people whose symptoms remain troublesome despite medicines, allergen immunotherapy by injections or sublingual tablets/drops may reduce symptoms and medication needs over time. This approach is most useful when a specific allergen is clearly identified. It should be supervised by trained clinicians because allergic reactions can occur.

In children, treatment principles are similar, but age, sleep effects, school performance, and correct spray technique matter. Sedating first-generation antihistamines are generally avoided because they can impair alertness and learning.

When to see a clinician

See a clinician if symptoms are frequent, affect sleep, school, work, or exercise, or do not improve with basic measures. Medical review is also important if you have wheezing, shortness of breath, recurrent sinus infections, ear symptoms, or suspected asthma.

Seek assessment sooner if you have one-sided nasal blockage, repeated nosebleeds, facial pain, fever, thick foul-smelling discharge, or loss of smell that is new or severe, because these features may suggest another diagnosis. Children with chronic mouth breathing, snoring, poor sleep, or hearing concerns should also be evaluated.

Limitations and open questions

Allergic rhinitis is common and usually manageable, but diagnosis is not always straightforward. Symptoms overlap with non-allergic rhinitis and viral infections, and some people have mixed disease. Allergy testing shows sensitization, not always clinically important allergy, so results need careful interpretation.

Evidence strongly supports intranasal corticosteroids, antihistamines, and immunotherapy in selected patients, but response varies. Environmental control measures are sensible, yet studies show mixed benefit for some single interventions when used alone. Research continues on how pollution, climate change, microbiome changes, and early-life exposures affect allergic rhinitis risk and severity.

Another open question is how best to personalize treatment. Some patients mainly have congestion, others have eye symptoms or asthma overlap, and not all respond the same way to standard therapy. If symptoms persist despite treatment, a clinician may need to reassess the diagnosis, technique, adherence, and possible coexisting conditions.