Allergic rhinitis is a widespread condition that affects individuals across all age groups. Characterized by symptoms such as sneezing, nasal congestion, and itchy eyes, this allergic reaction is triggered by exposure to environmental allergens.
-
Studies have shown that allergic rhinitis has become increasingly common in Hong Kong over the past two decades. Among school-aged children, the number of those experiencing symptoms rose from around 44% in the mid-1990s to over 56% by 2015 . Factors such as air pollution, high humidity, and year-round exposure to indoor allergens contribute to this upward trend.
-
What is Allergic Rhinitis?
Allergic rhinitis is an inflammatory condition of the nasal passages that occurs when the immune system overreacts to certain airborne substances. These substances, known as allergens, are typically harmless to most people but can trigger a reaction in individuals with allergies.
-
There are two primary types of allergic rhinitis: seasonal and perennial. Seasonal allergic rhinitis tends to occur during specific times of the year, such as spring or autumn, when pollen counts are high. Perennial allergic rhinitis, on the other hand, is persistent throughout the year and usually caused by indoor allergens. Although not life-threatening, allergic rhinitis can significantly impact work performance, school attendance, sleep quality, and general well-being.
-
Common allergens include:
●Dust mites ●Pollen | ●Pet dander ●Mold spores |
-
Depending on the type of allergen and the timing of exposure, allergic rhinitis may be classified as:
Seasonal allergic rhinitis | Perennial allergic rhinitis |
Often triggered by outdoor allergens such as pollen from trees, grasses, or weeds. | Caused by year-round exposure to indoor allergens such as dust mites and pet hair. |
-
The immune system identifies these allergens as threats and releases histamines and other chemicals, leading to inflammation and symptoms in the nose, eyes, and throat.
-
Common Symptoms of Allergic Rhinitis
Individuals with allergic rhinitis may experience a range of symptoms that vary in intensity. Common symptoms include:
●Frequent sneezing ●Runny or congested nose ●Itchy nose, eyes, or throat ●Watery eyes | ●Postnasal drip ●Coughing ●Fatigue due to poor sleep |
-
These symptoms may be mistaken for the common cold, but unlike a cold, allergic rhinitis does not cause fever and may persist for weeks or longer. Individuals who experience symptoms regularly or during specific seasons should consider seeking medical advice for further evaluation.
-
Why Allergic Rhinitis is So Common in Hong Kong
Several environmental and lifestyle factors contribute to the high prevalence of allergic rhinitis in Hong Kong:
● Air pollution: High levels of pollutants can aggravate the nasal passages and worsen allergic reactions.
● Humidity: The humid climate supports the growth of mold and dust mites, which are common indoor allergens.
●Urban living: Close quarters and limited ventilation in residential buildings can increase exposure to allergens.
● Occupational exposure: Individuals working in environments with dust or chemicals may be at greater risk.
-
Additionally, increased awareness and improved diagnostic tools have led to higher rates of detection, particularly among children and the working population.
-
Diagnosis: How Is It Identified?
Diagnosis of allergic rhinitis generally begins with a consultation that includes a detailed review of the patient’s medical history and a physical examination. Physicians will inquire about symptom frequency, duration, seasonal patterns, and any known or suspected triggers. This helps determine whether symptoms are consistent with allergic rhinitis or if other conditions, such as sinusitis or a common cold, may be involved.
-
If allergic rhinitis is suspected but the specific triggers are unclear, additional diagnostic tests may be recommended:
Skin prick test | A small drop of a suspected allergen is placed on the patient’s skin, usually on the forearm or back. The skin is then gently pricked so the allergen can enter the surface layer. If a red, raised bump appears within 15–20 minutes, it may indicate an allergic response. This test helps identify reactions to common allergens such as dust mites, pollen, mold, or pet dander. |
Blood tests (such as specific IgE testing) | This involves drawing a blood sample to measure the presence of allergen-specific immunoglobulin E (IgE) antibodies. Blood tests are often used when skin testing is not advisable, such as in individuals with skin conditions, those taking certain medications, or young children. |
Nasal endoscopy | In cases where symptoms persist despite treatment or when physical blockages are suspected, a nasal endoscopy may be performed. This involves inserting a thin, flexible tube with a camera into the nasal passages to examine the nasal lining and structures. It can help rule out structural issues such as nasal polyps, deviated septum, or chronic sinus inflammation. |
-
In some cases, a combination of tests may be used to ensure a comprehensive understanding of the condition. Accurate diagnosis not only confirms the presence of allergic rhinitis but also helps identify the specific allergens responsible, allowing for more targeted treatment and long-term symptom control.
-
Treatment and Management Options
Managing allergic rhinitis involves a combination of medication, lifestyle adjustments, and in some cases, immunotherapy.
Medication.-
-
Several medications are available to help control symptoms:
-
Antihistamines | Reduce sneezing, itching, and runny nose by blocking histamines. |
Nasal corticosteroids | Help decrease inflammation in the nasal passages. |
Decongestants | Provide short-term relief of nasal congestion. |
Leukotriene receptor antagonists | Used for patients with concurrent asthma or more severe allergies |
-
These medications may be available over the counter or by prescription and should be used under the guidance of a healthcare professional.
-
Lifestyle and Environmental Control
Minimizing exposure to allergens is a key component of long-term management. Recommended steps include:
●Using air purifiers with HEPA filters ●Regularly washing bed linens and curtains ●Vacuuming with a HEPA filter-equipped cleaner
| ●Avoiding carpets and upholstered furniture ●Keeping windows closed during high pollen periods ●Showering and changing clothes after spending time outdoors |
-
These measures can help reduce the allergen load in living and working environments, especially for those with perennial symptoms.
-
Immunotherapy
For individuals who do not respond well to standard treatments or prefer a long-term solution, immunotherapy may be an option. This involves gradually exposing the immune system to increasing amounts of the allergen to build tolerance.
-
Types of immunotherapy include:
● Allergy shots (subcutaneous immunotherapy)
●Sublingual immunotherapy (tablets or drops placed under the tongue)
-
Immunotherapy is typically administered over several years and is most effective when tailored to specific allergens identified during testing.
-
Taking Control of Allergic Rhinitis
Allergic rhinitis is a common and manageable condition that affects a significant portion of the population in Hong Kong. It can have a substantial impact on quality of life, but with timely diagnosis and appropriate treatment, most individuals can achieve effective symptom control.
-
Whether through medication, lifestyle changes, or immunotherapy, managing allergic rhinitis requires a comprehensive approach that addresses both the symptoms and their underlying triggers. Individuals experiencing persistent or severe symptoms are encouraged to seek medical advice to develop a personalized management plan.
-
Sources:
Lee, S.-L., Lau, Y.-L., Wong, W. H.-S., & Tian, L.-W. (2022). Childhood wheeze, allergic rhinitis, and eczema in Hong Kong: ISAAC study from 1995 to 2015. International Journal of Environmental Research and Public Health, 19(24), 16503. https://doi.org/10.3390/ijerph192416503
![[Aug] Blog 2 - Featured Image_R0](/Upload/news/44/photo/4b37638550084afcbd910e4be43e1be6.jpg)