What is allergic rhinitis?
Allergic rhinitis is a condition where the nasal lining becomes inflamed due to allergies. It typically presents with a runny nose, stuffy nose, watery red eyes and with bouts of sneezing. Allergic rhinitis occurs when the immune system reacts to the presence of allergens which make contact with the nasal lining. Animal dander, dust and pollen are some of the more common allergens.
Studies indicate that allergic rhinitis may affect as many as 40 million Americans but it is believed that it could affect up to 20% of the population. Many people do not seek treatment for it and attempt to manage it with over-the-counter (OTC) medication. Sometimes allergic rhinitis is seen with asthma or atopic dermatitis (eczema) as part of the allergic triad that tends to affect children.
Read more on rhinitis.
Types and Allergens
Allergic rhinitis may occur only at certain times of the year and this is known as seasonal allergic rhinitis. This is also referred to as hay fever. At other times it may persist throughout the year and is known as perennial allergic rhinitis. Most people do not differentiate between seasonal and perennial allergic rhinitis and the term hay fever is used to describe both types.
Allergens are the harmless substances that trigger a reaction. While it will not affect most people, those with allergies have a hypersensitive immune system which quickly reacts to these substances.
- Seasonal allergens: pollen (tree, grass, weed, flower) and mold spores.
- Perennial allergens: animal hair/fur (dander), house dust mites, cockroaches and molds.
Sometimes allergic rhinitis may be episodic or sporadic. In these instances the rhinitis is not present year round but arises in episodes even though it is not within seasons specific for allergens like pollen.
Causes of Allergic Rhinitis
The immune system has a host of defences to protect the body. One of the mechanisms is to trigger inflammation – a response that prevents tissue damage and recruits immune cells and chemicals to the area under threat. This is necessary to prevent an infection and neutralize substances that may be harmful to the body.
However, in an allergy this reaction is prematurely triggered by harmless substances known as allergens. The exact reason why some people are allergic and others are not is not always clear. There appears to be a hereditary factors involved in many instances. This means that a person’s risk of developing allergic conditions is higher if a parent or sibling has it.
Other reasons why some people are at greater risk is if there are other allergic conditions like atopic dermatitis present. People who work in environments where they are constantly exposed to allergens are also more likely to develop allergic rhinitis. Children born to mothers who smoke during pregnancy or within their first year of life are also at greater risk.
Signs and Symptoms
The signs and symptoms of allergic rhinitis are due to the inflammation of the lining in the nasal cavity. This mucous membrane lining is continuous with the lining of the paranasal sinuses. Therefore many people with allergic rhinitis may also have allergic sinusitis. Collectively this is referred to as rhinosinusitis.
Signs and symptoms include:
- Runny nose
- Stuffed nose (nasal congestion)
- Itchy nose
- Red, watery and itchy eyes
Most people with allergic rhinitis will experience other symptoms due to nasal inflammation. This may include a nasal tone to the voice, darkness and puffiness under the eyes, postnasal drip with a cough, dry mouth, snoring, headaches, loss of smell and fatigue. There may also be nasal and/or sinus infections as bacteria are trapped due to the congestion. Headaches with fever and burning or pain the nose are more likely associated with these infections.
Treatment of Allergic Rhinitis
The treatment of allergic rhinitis can be difficult at times. While there are various drugs to ease symptoms, reduce the severity of the condition and to some extent prevent episodes, these drugs are not a cure for allergic rhinitis. The focus is on managing allergic rhinitis in the long term both by using medication and instituting lifestyle changes to minimize or prevent episodes.
Treatment of allergic rhinitis involves both over-the-counter (OTC) and prescription medication. Milder cases may be effectively treated and managed with OTC medication while severe cases may require prescription medication and a more aggressive treatment approach.
Read more on allergy medication.
- Antihistamines are one of the more common drugs used in allergic rhinitis. It minimizes the action of histamine which is secreted in allergic reactions and one of the main inflammatory chemicals to cause nasal inflammation.
- Corticosteroids are used for severe allergic rhinitis and maybe used on a long term basis to prevent episodes. It can be used in the form of nasal sprays, pills for adults or syrups for children. Corticosteroids reduce nasal inflammation.
- Decongestants also aim to reduce inflammation and reduce symptoms like excessive mucus production. It acts by constricting the tiny blood vessels in the nasal mucosa which dilate as a result of inflammation. It is usually used in the form of nasal sprays.
- Leukotriene modifiers are prescription drugs that are an alternative to antihistamines. It works by blocking the immune chemical leukotriene which is released by certain immune cells and is also responsible for inflammation.
- Cromolyns work by blocking a type of immune cell known as mast cells from releasing the chemical histamine that is responsible for inflammation in allergic reactions. It is available in the form of a nasal spray.
- Anticholinergic agents inhibit mucus secretion by the lining of the nasal cavity. It is usually used in conjunction with other allergy medication. These drugs only work to reduce the excess mucus secretion.
- Immunotherapy involves exposing a person to small amounts of the allergen. This allows the body to become accustomed to it without triggering inflammatory reactions in its presence. It may be available as injections just under the skin or as tablets that are dissolved under the tongue.
Prevention is another important aspect in the treatment and management of allergic rhinitis. It involves limiting exposure to allergens. This is not always possible but the extent of the reaction can be reduced by minimizing the quantity of allergens that are inhaled.