Patients are often not sure how to differentiate between symptoms of allergies, the common cold, and flu.
What is allergic rhinitis?
South Africa has one of the largest floral kingdoms in the world. Cape Town is a windy city with a very high pollen count especially during our summer with the South Easter.
Allergic Rhinitis (AR), or hay fever, is an IgE antibody-mediated allergic response to a specific allergen. It is an inflammatory disease characterized by symptoms of nasal congestion, sneezing, itchy eyes/mouth/nose/throat, puffy swollen eyelids, coughing, post-nasal drip and rhinorrhoea (a runny nose). AR can be classified as being seasonal (e.g. seasonal exposure to pollens from grass, trees, and weeds) or perennial (year-round exposure to e.g. house dust mites, pet hair, mold). Some individuals might experience both types of AR with perennial symptoms getting worse during specific pollen seasons. There are also nonallergic causes of rhinitis following exposure to cigarette smoke, perfumes, cleaning products etc.
Patients with inhalant allergies can be screened using either a skin prick test or by blood tests for IgE. IgE is a type of antibody made by the immune system in response to an allergen. In patients with allergies, a high level of IgE can be found when the body overreacts to a certain allergen. In patients with asthma or rhinitis with exacerbation in spring, testing for tree pollens is also recommended using Tree pollen mix 1 or Tree pollen mix 2. The most common allergenic tree pollen in South Africa are plane tree, oak, olive, cypress, eucalyptus, pine, acacia, willow, poplar, mulberry, elm, ash, and elder.
Allergic rhinitis management and treatment
Environmental control to avoid allergens that trigger symptoms:
- Stay indoors as much as possible during peak pollen times (midmorning and early evening) and windy periods.
- Wear glasses or sunglasses when outdoors to minimize pollen contact with your eyes.
- Keep windows closed during peak pollen season.
- Use mite-proof covers for bedroom linen to reduce exposure to dust mites.
- Reduce mold exposure by regularly cleaning bathrooms/kitchens and using a dehumidifier in damp humid basement areas.
- Clean floors with mop rather than sweeping.
- Wash hands after petting animals.
- If allergic to a household pet, keep animal outside as much as possible and especially out of the bedroom to reduce exposure to allergens while you sleep.
- Replace carpets with wood or tile.
Medications for allergens:
- Intranasal corticosteroids (INCS) have potent anti-inflammatory properties and are the single most effective drug class for treating allergic rhinitis. They reduce symptoms of sneezing, itchiness, rhinorrhoea and congestion. Continuous use of INCS during pollen is recommended and more effective than intermittent (as needed) use. Side-effects of INCS include nasal dryness, burning, stinging, blood tinged secretions and epistaxis. The spray should be directed away from the centre of the nose/septum and towards the eye on the same side as the nostril being sprayed.
- Antihistamines counter the effects of histamine released by our body during an allergic reaction and relieve itching, sneezing and rhinorrhoea. They are available as eye drops, oral tablets, syrups and nasal sprays. Antihistamines work most effectively when taken before the symptoms develop. The older generation antihistamines can cause drowsiness and sedation.
- Decongestants help to relieve the stuffiness and pressure caused by swollen nasal tissue. These are available as nasal sprays and oral medications. Prolonged usage of decongestant nasal sprays can result in rhinitis medicamentosa (rebound swelling of nasal tissue) which can be managed by stopping its usage. Oral decongestants don’t cause rebound swelling but are best avoided in patients with heart disease, hyperthyroidism.
- Saline nasal spray can help counteract symptoms such as dry nasal passage and thick nasal mucus. These can be used as often as needed unlike decongestant nasal sprays.
- Leukotriene antagonists block the release of inflammatory mediators from mast cells, eosinophils, basophils which contributes to the symptoms of AR. This is also used in the treatment of asthma so can be considered in patients with asthma and rhinitis.
Although definitive diagnosis depends on the finding of an IgE-mediated response to a specific allergen via cutaneous or blood testing, it is reasonable in practice to make an initial diagnosis and start therapy based on history and examination. A good response supports the diagnosis of AR and further testing is not needed. Specific IgE testing is warranted in patients who fail to respond to empiric therapy or diagnosis is uncertain or causative allergen needs to be identified to target treatment.
References: American College of Allergy, Asthma and Immunology; Annals of Allergy, Asthma and Immunology: Treatment of seasonal allergic rhinitis 2017 guideline