By Renova Hospitals
December 11, 2025
Hay Fever (Allergic Rhinitis): Complete Medical Guide, Causes, Symptoms, Diagnosis & Advanced Treatment - Renova Hospitals
Hay fever, medically known as allergic rhinitis, is a highly prevalent inflammatory condition of the nasal passages triggered by exposure to airborne allergens. When the immune system reacts to allergens like pollen, dust mites, mould spores or pet dander, it initiates a chain of inflammatory responses known as a hay fever allergic reaction.
This causes sneezing, nasal congestion, watery eyes, itching and throat irritation. Although not life-threatening, untreated allergies can significantly impair sleep quality, daily functioning, work performance and may worsen respiratory conditions such as asthma, leading to persistent asthma hay fever cough.
This causes sneezing, nasal congestion, watery eyes, itching and throat irritation. Although not life-threatening, untreated allergies can significantly impair sleep quality, daily functioning, work performance and may worsen respiratory conditions such as asthma, leading to persistent asthma hay fever cough.
At Renova Hospitals, our experts offer advanced outpatient allergy care, including diagnostics, environmental management guidance, allergy hay fever medication, immunotherapy and specialised treatment plans tailored for chronic, seasonal, perennial and acute hay fever.
Overview
Hay fever is an immune-mediated response to particles that are otherwise harmless for most individuals. It is not an infection, nor is it contagious. Instead, the immune system misinterprets airborne particles as dangerous invaders and releases chemicals like histamine and leukotrienes, causing nasal and ocular inflammation.
Key insights:
- Hay fever is caused by allergen exposure, not viruses or bacteria.
- Symptoms can be seasonal (spring, late summer), perennial (year-round) or episodic.
- The neural network known as the ganglion of hay fever plays an important role in how the nose reacts to allergens.
- Patients often develop chronic sinus problems if left untreated.
- Long-term relief is possible through immunotherapy, environmental modification and compliance with treatment.
Types of Hay Fever (Allergic Rhinitis)
To help understand how symptoms vary between individuals, hay fever is divided into subtypes based on triggers and timing.
1. Seasonal Allergic Rhinitis
Occurs when the immune system reacts to outdoor pollens.
Triggered by pollen from:
• Trees (spring) – birch, oak, cedar and eucalyptus pollens peak early in the year.
• Grasses (late spring–summer) – grass pollen is the most common global allergen.
• Weeds (late summer–autumn) – ragweed and other weeds release highly allergenic pollens.
• Trees (spring) – birch, oak, cedar and eucalyptus pollens peak early in the year.
• Grasses (late spring–summer) – grass pollen is the most common global allergen.
• Weeds (late summer–autumn) – ragweed and other weeds release highly allergenic pollens.
2. Perennial Allergic Rhinitis
Symptoms persist year-round due to indoor allergens.
Triggered by:
• Dust mites – thrive in mattresses, upholstery and carpets.
• Pets – animal dander and saliva are potent triggers.
• Mould spores – especially in humid or poorly ventilated spaces.
• Cockroach allergens – common in urban environments.
• Dust mites – thrive in mattresses, upholstery and carpets.
• Pets – animal dander and saliva are potent triggers.
• Mould spores – especially in humid or poorly ventilated spaces.
• Cockroach allergens – common in urban environments.
3. Episodic Allergic Rhinitis
Symptoms appear only during direct allergen exposure (e.g., visiting a home with pets, sudden dust exposure).
4. Occupational Allergic Rhinitis
Workplace exposures cause recurrent symptoms. Triggers include:
• Chemicals – formaldehyde, cleaning agents, fumes.
• Laboratory animals – dander, urine proteins.
• Pollens in agricultural settings – high-volume exposure.
• Printing inks – volatile organic compounds.
• Industrial dust – metal or wood particles.
Severity Classification
Understanding severity guides treatment intensity.
Mild Hay Fever
• Minimal symptoms that may be intermittent or tolerable without daily therapy.
• No major impact on sleep or work, indicating mild mucosal involvement.
Moderate to Severe Hay Fever
• Persistent congestion indicating significant mucosal swelling.
• Eye symptoms such as redness, tearing and itching.
• Sleep disruption due to airway obstruction.
• Daytime fatigue, often underestimated but clinically significant.
• Impact on work, school or quality of life, requiring active intervention.
Acute Hay Fever
Sudden, intense flare-ups marked by rapid immune activation.
Patients may experience:
• Repeated sneezing episodes
• Watery, irritated eyes
• A sharp rise in hay fever symptoms after large-dose allergen exposure
These episodes reflect heightened immune sensitivity.
Patients may experience:
• Repeated sneezing episodes
• Watery, irritated eyes
• A sharp rise in hay fever symptoms after large-dose allergen exposure
These episodes reflect heightened immune sensitivity.
Pathophysiology: How the Body Reacts
When allergens enter the nose:
- The immune system misidentifies them as threats, creating unnecessary inflammation.
- IgE antibodies bind to mast cells, preparing the immune system for overreaction.
- Upon re-exposure, mast cells release histamine, leukotrienes and cytokines.
- Blood vessels widen, leading to swelling and congestion.
- Mucus glands activate, increasing nasal discharge.
- Nerve pathways, including the ganglion of hay fever, amplify sneezing, itching and irritation.
Over time, chronic inflammation alters nasal structures, increasing long-term sensitivity.
Environmental Science Behind Triggers
Allergen intensity fluctuates with environmental conditions. Before the bullet points, it's important to note that microclimate factors can dramatically change symptoms from day to day.
Allergen load varies with:
• Weather patterns – warm, windy days carry more pollen.
• Humidity levels – high humidity promotes dust mite and mould growth.
• Pollution – particulate matter binds to allergens, making them more reactive.
• Wind speed – spreads pollen rapidly across large distances.
• Indoor ventilation – poor airflow traps allergens indoors.
• Pet exposure – allergen proteins remain airborne for hours.
• Urban vs rural environment – cities often have worse symptoms due to pollution–pollen interactions.
• Humidity levels – high humidity promotes dust mite and mould growth.
• Pollution – particulate matter binds to allergens, making them more reactive.
• Wind speed – spreads pollen rapidly across large distances.
• Indoor ventilation – poor airflow traps allergens indoors.
• Pet exposure – allergen proteins remain airborne for hours.
• Urban vs rural environment – cities often have worse symptoms due to pollution–pollen interactions.
Poor air quality weakens immune defences, increasing the severity of hay fever symptoms and frequency of hay fever allergic reaction episodes.
Climate change lengthens pollen seasons, intensifying the burden of acute hay fever.
Symptoms and Causes
Common Symptoms
- Sneezing
- Runny nose
- Itchy or blocked nose
- Watery, red, or swollen eyes
- Itchy throat or palate
- Headache and sinus pressure
- Postnasal drip
- Fatigue and sleep disturbance
- Difficulty concentrating
- Reduced smell
- Persistent asthma hay fever cough due to airway irritation
Children may show:
- Frequent nose rubbing ("allergic salute")
- Mouth breathing
- Irritability
- Dark circles under eyes ("allergic shiners")
What Causes Hay Fever?
Hay fever is caused by hypersensitivity of the immune system to airborne particles. The allergens vary by region but follow predictable patterns.
Primary hay fever causes include:
• Grass, tree and weed pollen – potent outdoor triggers.
• Mould spores – especially problematic in damp seasons.
• Dust mites – major indoor allergens.
• Pet dander – protein particles from skin, saliva, and urine.
• Cockroach allergens – often related to urban living conditions.
• Mould spores – especially problematic in damp seasons.
• Dust mites – major indoor allergens.
• Pet dander – protein particles from skin, saliva, and urine.
• Cockroach allergens – often related to urban living conditions.
Secondary aggravating triggers:
• Air pollution – enhances allergic reactivity.
• Tobacco smoke – inflames mucosal surfaces.
• Perfumes and aerosols – irritants that worsen congestion.
• Cold or dry air – increases mucosal vulnerability.
• Tobacco smoke – inflames mucosal surfaces.
• Perfumes and aerosols – irritants that worsen congestion.
• Cold or dry air – increases mucosal vulnerability.
These triggers heighten inflammation and make acute hay fever episodes more likely.
Risk Factors
Before listing them, it is essential to emphasise that risk factors amplify immune over reactivity rather than directly causing allergies.
Individuals are at higher risk if they have:
• Family history of allergies – genetic predisposition increases IgE sensitivity.
• Asthma or eczema – part of the “atopic triad.”
• High pollen exposure – outdoor workers are more vulnerable.
• Indoor mould growth – chronic exposure leads to persistent hay fever symptoms.
• Poor air filtration at home – allergens accumulate quickly.
• Pets in living spaces – constant allergen shedding.
• Occupational exposure to allergens – particularly in agriculture, laboratories or manufacturing.
• Early childhood sensitisation – early allergen exposure shapes immune patterns.
Diagnosis and Tests
A thorough evaluation helps differentiate hay fever from viral infections or sinusitis.
Diagnostic methods include:
1. Skin Prick Test
Quick assessment of IgE response to multiple allergens.
2. Specific IgE Blood Test
Useful when skin testing isn't feasible.
3. Nasal Endoscopy
Detects swelling, polyps or structural issues.
4. Imaging (CT of Sinuses)
Used if chronic sinus complications are suspected.
5. Lung Function Tests
Especially important in patients with asthma hay fever cough, or suspected asthma.
6. Nasal Smear
Identifies eosinophils, indicating allergic inflammation.
Immunotherapy
Allergy shots for hay fever are the only therapy that modifies immune behaviour rather than masking symptoms.
Benefits include:
• Reduced sensitivity to allergens over time
• Lower reliance on medications
• Long-lasting improvement
• Asthma prevention in high-risk patients
• Closest pathway to how to cure hay fever permanently
• Lower reliance on medications
• Long-lasting improvement
• Asthma prevention in high-risk patients
• Closest pathway to how to cure hay fever permanently
Immunotherapy retrains the immune system, decreasing IgE responses and enhancing tolerance.
Lifestyle, Environmental & Home Management
Home modifications
- HEPA air purifiers
- Hypoallergenic bedding
- Mold control
- Frequent vacuuming
- Removal of carpets
Outdoor precautions
- Wearing masks during high-pollen counts
- Checking daily pollen forecasts
- Avoiding early morning outdoor activity
Personal hygiene
- Showering after outdoor exposure
- Washing hair and clothes
- Rinsing nasal passages with saline
Diet
Some evidence suggests that anti-inflammatory diets may ease chronic allergy symptoms.
Supportive foods:
- Omega-3-rich foods
- Turmeric
- Green tea
- Fruits and vegetables high in antioxidants
Complications of Untreated Hay Fever
Untreated or poorly managed hay fever can lead to:
- Chronic sinusitis
- Ear infections
- Nasal polyps
- Worsening asthma
- Persistent asthma hay fever cough
- Sleep disturbance
- Attention and memory issues
- Reduced work performance
- Frequent absenteeism
Children may develop speech issues or academic delay due to chronic nasal blockage.
Hay Fever in Special Populations
Children
Early identification prevents long-term airway complications.
Pregnant Women
Medication choices must be carefully supervised.
Older Adults
More prone to side effects; dryness may mimic other illnesses.
Asthma Patients
More likely to develop severe hay fever allergic reaction with bronchial involvement.
Psychological & Cognitive Effects
Chronic hay fever symptoms can cause:
- Poor sleep
- Irritability
- Reduced productivity
- Difficulty focusing
- Social withdrawal during severe episodes
Long-Term Management
Effective lifelong control requires:
- Allergen identification
- Consistent use of medication
- Environmental management
- Immunotherapy
- Monitoring for asthma
Patients with persistent or severe symptoms benefit from long-term follow-up with an allergy specialist.
Prevention Strategies
Preventive approach includes:
- Avoiding allergens where possible
- Improving indoor air quality
- Maintaining nasal hygiene
- Using preventive nasal sprays during pollen seasons
- Managing humidity
- Avoiding pets in bedrooms
- Keeping homes dust-free
When to Seek Medical Assistance
Consult a Renova specialist if:
- Symptoms last longer than two weeks
- Over-the-counter medicines fail
- You develop worsening wheeze or asthma hay fever cough
- Sinus symptoms become chronic
- Sleep is significantly disrupted
When Emergency Care Is Required
Symptoms needing immediate care:
- Difficulty breathing
- Chest tightness
- Severe and sudden swelling
- Signs of anaphylaxis
- High fever (indicates infection, not hay fever)
Outlook / Prognosis
Patients with hay fever generally have an excellent prognosis with proper treatment.
Expected outcomes:
- Symptom improvement within weeks of starting therapy
- Long-term reduction with immunotherapy
- Reduced asthma complications
- Significant improvement in sleep and daily functioning
Immunotherapy offers the closest path toward curing hay fever permanently, though results vary.
Early Treatment Helps You Breathe Better, Sleep Better and Live Better
Hay fever is manageable with proper evaluation, environmental control, allergy hay fever medication, and long-term solutions like allergy shots for hay fever. Renova Hospitals provides specialised care to diagnose triggers, reduce symptoms, and improve respiratory health. Early treatment prevents complications, reduces asthma risk and ensures long-term quality of life.
Frequently Asked Questions
1. What exactly is hay fever?
Hay fever is an allergic inflammation of the nose caused by exposure to airborne allergens like pollen, dust mites and pet dander. These triggers lead to a hay fever allergic reaction, resulting in sneezing, congestion and itchy, watery eyes.
2. What are the most common hay fever symptoms?
Common hay fever symptoms include sneezing, runny or blocked nose, itchy eyes, throat irritation and postnasal drip. Some patients also develop breathing difficulty or an associated asthma hay fever cough.
3. What causes hay fever?
Hay fever is caused by an exaggerated immune response to allergens. Major hay fever causes include pollen, dust mites, moulds, pet dander and environmental irritants such as smoke and pollution.
4. Is hay fever lifelong?
Not always. Some people experience improvement with age, while others continue to have hay fever symptoms throughout life. Children may outgrow certain allergies, but adults can develop new sensitivities over time.
5. Does hay fever become worse each year?
It can. Repeated exposure to allergens may increase sensitivity for some individuals, leading to stronger seasonal flare-ups or more frequent acute hay fever episodes.
6. Is hay fever linked to food allergies?
Yes, in some cases. Certain individuals experience "cross-reactivity," where pollen allergies trigger symptoms when eating related foods. This is more common in people with strong pollen-related hay fever allergic reaction patterns.
7. Can hay fever be prevented?
Complete prevention is unlikely, but symptom intensity can be reduced by minimising allergen exposure, improving indoor air quality and using preventive allergy hay fever medication during high-pollen seasons.
8. What medications treat hay fever?
Treatment may include antihistamines, nasal corticosteroids, decongestants and leukotriene modifiers. These allergy hay fever medication options reduce inflammation, itching and congestion.
9. Are allergy shots effective for long-term control?
Yes. Allergy shots for hay fever (immunotherapy) are the only treatment that modifies the immune system’s response to allergens. For many patients, this offers the closest pathway to how to cure hay fever permanently.
10. Can hay fever affect asthma or breathing?
Yes. Hay fever can irritate the lower airways, leading to wheezing or asthma hay fever cough. Managing nasal allergies often reduces asthma symptoms and improves long-term respiratory health.
