Sign & Symptoms
- Runny nose
- Itchy and blocked nose
- Itchy eyes
- Altered sense of smell
What Causes It
Allergic rhinitis is caused by an over response of the body’s immune system to non-infectious particles such as pollen, dust mites, animal hair, food, etc.
The most common aeroallergen locally is house dust mites. Other common inhaled allergens include cockroach and animal danders while common ingested allergens include milk, egg white, soy, fish and nuts.
About The Condition
Allergic Rhinitis is an inflammation of the nasal passages and is usually associated with runny nose, sneezing, itch and blocked nose.
Rhinological and ENT allergic conditions are among the most common and debilitating complaints of the population in Singapore. An epidemiological survey undertaken by the department showed a prevalence of 13% of perennial rhinitis in Singapore.
Nasal allergy or Allergic Rhinitis is a common nasal problem worldwide. There is a high association between allergic rhinitis, asthma and chronic sinus condition. It tends to run in families and can cause negative impact in the quality of life of people suffering from this condition. It is now recognised that early intervention in patients with allergic rhinitis can result in a decreased incidence of allergic asthma. Patients with allergic rhinitis are often inadequately treated as many do not seek treatment till their conditions are severe and affect their daily activities. Advances in diagnostic tests as well as medical and surgical treatment have resulted in better and more specific therapies. Management strategies include allergen identification and avoidance, pharmacotherapy, immunotherapy and surgery.
Diagnosis and Treatment Options
At NUH, we have a dedicated Otolarynologic (ENT) Allergy Clinic located within the ENT Centre. From its beginnings as a part-time service in 1995, it has been established as a fully specialised clinical service since 2002, with a trained full-time staff comprising physicians, allergy nurses and research scientists. The Clinic evaluates and treats both adults and children with Otolaryngologic Allergy. These include allergic rhinitis and other nasal diseases like sinusitis and nasal polyps, and food allergy.
A full range of diagnostic services is available, with individualized patient testing under the supervision of a specialist physician.
These may include blood (RAST), skin prick and intradermal tests, and endoscopic examination of the nose and upper airway.
After consultation and testing, therapeutic options will be explored. To improve patient management, a dedicated allergy nurse in the Otolaryngologic Allergy Clinic will educate and counsel the patients on the nature of allergy, the environmental factors that can be modified to improve symptoms, the importance of pharmacotherapy compliance as well as impart correct techniques in application of nasal sprays.
In addition to standard drug therapy, the Clinic offers immunotherapy which can be administered by the subcutaneous or sublingual route.
The Allergy Service also has an important role in research and medical education. It conducts and coordinates clinical trials on all aspects of Otolaryngologic Allergy, and its staff has accumulated an impressive list of international abstracts and publications. It also conducts local and regional meetings and teaching workshops, including successful workshops on Otolaryng
ologic Allergy and Immunotherapy for regional physicians.
As the Otolaryngologic Allergy Clinic is a specialised ENT service, it does not accept direct referrals. Potential patients are first assessed by an Otolaryngologist to exclude other causes of their symptoms before being directed to the Clinic for management.
Skin Prick Test (SPT)
SPT is performed on the forearm, to test for Inhalant Allergy. Some of the common inhalant allergens are house dust mites, dog and cat dander, cockroach, mould, grass and tree pollens. SPT is usually well tolerated, even in young children, and results are ready in twenty minutes.
Intradermal Provocative Food Test (IPFT)
This is an allergy test for Cyclical (non IgE-medicated) Food Allergy. It involves injecting small amounts of diluted food extracts onto the upper arm, and measurements of the reactions will be recorded at regular intervals. The whole process takes about three hours to complete, including explanation of test results.
Radioallergosorbent Test (RAST)
This is an allergy tests that involves collecting blood. It may be used to test for either Inhalant Allergy or Fixed (IgE-mediated) Food Allergy. Results could take up to two weeks to be ready. A blood sample for RAST is usually taken when skin conditions such as severe eczema or dermographic skin, prevent accurate testing or when the patient is taking medications (such as antihistamines, sedatives or antidepressants) that interfere with accurate testing.
The management of Inhalant Allergy also includes counselling of proper environmental control and/or advice on allergy products available. Based on the results of the allergy tests, the Allergy Nurses may offer advice on a range of measures that the patients could adopt to help reduce contact with or avoid what triggers the allergy symptoms.
For patients who have undergone the IPFT, the Allergy Nurse assists them to make sense of their test results, and explain the need for correct diet management. This is important if they hope to relieve their existing symptoms and achieve an improved quality of life. A change in their usual eating habits may be inevitable and they are encouraged to practice avoidance of the allergic food items for a sustained period of time.
This is a treatment that consists of gradually re-accustoming the body to the allergen responsible for the allergic reactions so as to modify (or perhaps entirely suppress) the body’s response.
This involves two successive phases:
- An initiation phase during which the dose of the allergen is gradually stepped up.
- The maintenance phase during which the maximum tolerated dose is administered for an extended period of time (at least three years).
Immunotherapy may be administered via subcutaneous injections or taken orally (sublingual).
Allergen avoidance - Allergen avoidance and pharmacotherapy are the first line treatment for patients with allergic rhinitis. Patients who do not respond adequately to the above measures will benefit from medication, specific immunotherapy, surgery or both, depending on the nature of their symptoms.
Medications – Nasal steroids and antihistamines are the mainstay of treatment. Intranasal or intraocular chromones and anti-leukotrienes can be added if necessary.
Immunotherapy - Immunotherapy (desensitisation therapy or allergy shots) is currently recognised as an effective treatment for allergic rhinitis. It has been used in our department with good clinical efficacy for many years. It can be administered by two routes, either subcutaneous (injection) or sublingual (under the tongue).
Surgery - Patients who have persistent nasal obstruction secondary to structural defects will benefit from surgery to correct them.
Nasal and Sinus Surgery
Besides medical treatment, there are many surgical options to treat various nasal conditions. Some procedures are performed on an outpatient basis in the ENT clinic, under local anesthesia. They include radiofrequency reduction of the inferior turbinates for treatment of nasal obstruction and simple palatal procedures for snoring such as palatal implants and radiofrequency application.
Image Guidance Endoscopic Sinus Surgery
Major operative procedures that are performed in the operating theatre can be done either as a day surgery or in-patient basis. They include open or endoscopic procedures to correct nasal deformities, treat sinus infections, nasal polyps or tumours. Most of the endoscopic sinus surgeries are performed using a computerised image guided system which aids in confirming important landmarks in the nose, hence adding to the safety of the surgery and allow for more complete clearance of diseased tissues.