Allergic rhinitis is inflammation of the inside of the nose caused by an allergen, such as pollen, dust, mould, or flakes of skin from certain animals.
It's a very common condition, estimated to affect around one in every five people in the UK.
Signs and symptoms
Allergic rhinitis typically causes cold-like symptoms, such as sneezing, itchiness and a blocked or runny nose. These symptoms usually start soon after being exposed to an allergen.
Some people only get allergic rhinitis for a few months at a time because they're sensitive to seasonal allergens, such as tree or grass pollen. Other people get allergic rhinitis all year round.
Most people with allergic rhinitis have mild symptoms that can be easily and effectively treated. But for some symptoms can be severe and persistent, causing sleep problems and interfering with everyday life.
The symptoms of allergic rhinitis occasionally improve with time, but this can take many years and it's unlikely that the condition will disappear completely.
When to see your GP
Visit your GP if the symptoms of allergic rhinitis are disrupting your sleep, preventing you carrying out everyday activities, or adversely affecting your performance at work or school.
A diagnosis of allergic rhinitis will usually be based on your symptoms and any possible triggers you may have noticed. If the cause of your condition is uncertain, you may be referred for allergy testing.
Allergic rhinitis is caused by the immune system reacting to an allergen as if it were harmful.
This results in cells releasing a number of chemicals that cause the inside layer of your nose (the mucous membrane) to become swollen and excessive levels of mucus to be produced.
Common allergens that cause allergic rhinitis include pollen – this type of allergic rhinitis is known as hay fever – as well as mould spores, house dust mites, and flakes of skin or droplets of urine or saliva from certain animals.
It's difficult to completely avoid potential allergens, but you can take steps to reduce exposure to a particular allergen you know or suspect is triggering your allergic rhinitis. This will help improve your symptoms.
If your condition is mild, you can also help reduce the symptoms by taking over-the-counter medications, such as non-sedating antihistamines, and by regularly rinsing your nasal passages with a salt water solution to keep your nose free of irritants.
See your GP for advice if you've tried taking these steps and they haven't helped. They may prescribe a stronger medication, such as a nasal spray containing corticosteroids.
Allergic rhinitis is caused by an allergic reaction to an allergen, such as pollen, dust and certain animals.
Oversensitive immune system
If you have allergic rhinitis, your immune system – your natural defence against infection and illness – will react to an allergen as if it were harmful.
If your immune system is oversensitive, it will react to allergens by producing antibodies to fight them off. Antibodies are special proteins in the blood that are usually produced to fight viruses and infections.
Allergic reactions don't occur the first time you come into contact with an allergen. The immune system has to recognise and "memorise" it before producing antibodies to fight it. This process is known as sensitisation.
After you develop sensitivity to an allergen, it will be detected by antibodies called immunoglobulin E (IgE) whenever it comes into contact with the inside of your nose and throat.
These antibodies cause cells to release a number of chemicals, including histamine, which can cause the inside layer of your nose (the mucous membrane) to become inflamed and produce excess mucus. This is what causes the typical symptoms of sneezing and a blocked or runny nose.
Allergic rhinitis is triggered by breathing in tiny particles of allergens. The most common airborne allergens that cause rhinitis are described below.
House dust mites
House dust mites are tiny insects that feed on the dead flakes of human skin. They can be found in mattresses, carpets, soft furniture, pillows and beds.
Rhinitis isn't caused by the dust mites themselves, but by a chemical found in their excrement. Dust mites are present all year round, although their numbers tend to peak during the winter.
Pollen and spores
Tiny particles of pollen produced by trees and grasses can sometimes cause allergic rhinitis. Most trees pollinate from early to mid-spring, whereas grasses pollinate at the end of spring and beginning of summer.
Rhinitis can also be caused by spores produced by mould and fungi.
Many people are allergic to animals, such as cats and dogs. The allergic reaction isn't caused by animal fur, but flakes of dead animal skin and their urine and saliva.
Dogs and cats are the most common culprits, although some people are affected by horses, cattle, rabbits and rodents, such as guinea pigs and hamsters.
However, being around dogs from an early age can help protect against allergies, and there's some evidence to suggest that this might also be the case with cats.
Some people are affected by allergens found in their work environment, such as wood dust, flour dust or latex.
Who's most at risk?
It isn't fully understood why some people become oversensitive to allergens, although you're more likely to develop an allergy if there's a history of allergies in your family.
If this is the case, you're said to be "atopic", or to have "atopy". People who are atopic have a genetic tendency to develop allergic conditions. Their increased immune response to allergens results in increased production of IgE antibodies.
Environmental factors may also play a part. Studies have shown certain things may increase the chance of a child developing allergies, such as growing up in a house where people smoke and being exposed to dust mites at a young age.
Diagnosing allergic rhinitis
Your GP will often be able to diagnose allergic rhinitis from your symptoms and your personal and family medical history.
They'll ask you whether you've noticed any triggers that seem to cause a reaction, and whether it happens at a particular place or time.
Your GP may examine the inside of your nose to check for nasal polyps.
Nasal polyps are fleshy swellings that grow from the lining of your nose or your sinuses, the small cavities inside your nose. They can be caused by the inflammation that occurs as a result of allergic rhinitis.
Allergic rhinitis is usually confirmed when medical treatment starts. If you respond well to antihistamines, it's almost certain that your symptoms are caused by an allergy.
If the exact cause of allergic rhinitis is uncertain, your GP may refer you to a hospital allergy clinic for allergy testing.
The two main allergy tests are:
skin prick test – where the allergen is placed on your arm and the surface of the skin is pricked with a needle to introduce the allergen to your immune system; if you're allergic to the substance, a small itchy spot (welt) will appear
blood test – to check for the immunoglobulin E (IgE) antibody in your blood; your immune system produces this antibody in response to a suspected allergen
Commercial allergy testing kits aren't recommended because the testing is often of a lower standard than that provided by the NHS or an accredited private clinic.
It's also important that the test results are interpreted by a qualified healthcare professional with detailed knowledge of your symptoms and medical history.
In some cases further hospital tests may be needed to check for complications, such as nasal polyps or sinusitis.
For example, you may need:
a nasal endoscopy – where a thin tube with a light source and video camera at one end (endoscope) is inserted up your nose so your doctor can see inside your nose
a nasal inspiratory flow test – where a small device is placed over your mouth and nose to measure the air flow when you inhale through your nose
a X-rays and a computer to create detailed images of the inside of the body
Treating allergic rhinitis
Treatment for allergic rhinitis depends on how severe your symptoms are and how much they're affecting your everyday activities.
In most cases treatment aims to relieve symptoms such as sneezing and a blocked or runny nose.
If you have mild allergic rhinitis, you can often treat the symptoms yourself.
You should visit your GP if your symptoms are more severe and affecting your quality of life, or if self-help measures haven't been effective.
It's possible to treat the symptoms of mild allergic rhinitis with over-the-counter medications, such as long-acting, non-sedating antihistamines.
If possible, try to reduce exposure to the allergen that triggers the condition. See preventing allergic rhinitis for more information and advice about this.
Cleaning your nasal passages
Regularly cleaning your nasal passages with a salt water solution – known as nasal douching or irrigation – can also help by keeping your nose free of irritants.
You can do this either by using a homemade solution or a solution made with sachets of ingredients bought from a pharmacy.
Small syringes or pots that often look like small horns or teapots are also available to help flush the solution around the inside of your nose.
To make the solution at home, mix half a teaspoon of salt and half a teaspoon of bicarbonate of soda (baking powder) into a pint (568ml) of boiled water that's been left to cool to around body temperature – do not attempt to rinse your nose while the water is still hot.
To rinse your nose:
stand over a sink, cup the palm of one hand and pour a small amount of the solution into it
sniff the water into one nostril at a time
repeat this until your nose feels comfortable – you may not need to use all of the solution
While you do this, some solution may pass into your throat through the back of your nose. The solution is harmless if swallowed, but try to spit out as much of it as possible.
Nasal irrigation can be carried out as often as necessary, but a fresh solution should be made each time.
Medication won't cure your allergy, but it can be used to treat the common symptoms.
If your symptoms are caused by seasonal allergens, such as pollen, you should be able to stop taking your medication after the risk of exposure has passed.
Visit your GP if your symptoms don't respond to medication after two weeks.
Antihistamines relieve symptoms of allergic rhinitis by blocking the action of a chemical called histamine, which the body releases when it thinks it's under attack from an allergen.
You can buy antihistamine tablets over the counter from your pharmacist without a prescription, but antihistamine nasal sprays are only available with a prescription.
Antihistamines can sometimes cause drowsiness. If you're taking them for the first time, see how you react to them before driving or operating heavy machinery. In particular, antihistamines can cause drowsiness if you drink alcohol while taking them.
If you have frequent or persistent symptoms and you have a nasal blockage or corticosteroids.
Corticosteroids help reduce inflammation and swelling. They take longer to work than antihistamines, but their effects last longer. Side effects from inhaled corticosteroids are rare, but can include nasal dryness, irritation and nosebleeds.
If you have a particularly severe bout of symptoms and need rapid relief, your GP may prescribe a short course of corticosteroid tablets lasting 5 to 10 days.
If allergic rhinitis doesn't respond to treatment, your GP may choose to add to your original treatment.
They may suggest:
increasing the dose of your corticosteroid nasal spray
using a short-term course of a decongestant nasal spray to take with your other medication
combining antihistamine tablets with corticosteroid nasal sprays, and possibly decongestants
using a nasal spray that contains a medicine called ipratropium, which will help reduce excessive nasal discharge
using a leukotriene receptor antagonist medication – medication that blocks the effects of chemicals called leukotrienes, which are released during an allergic reaction
If you don't respond to the add-on treatments, you may be referred to a specialist for further assessment and treatment.
Immunotherapy, also known as hyposensitisation or desensitisation, is another type of treatment used for some allergies.
It's only suitable for people with certain types of allergies, such as hay fever, and is usually only considered if your symptoms are severe.
Immunotherapy involves gradually introducing more and more of the allergen into your body to make your immune system less sensitive to it.
The allergen is often injected under the skin of your upper arm. Injections are given at weekly intervals, with a slightly increased dose each time.
Immunotherapy can also be carried out using tablets that contain an allergen, such as grass pollen, which are placed under your tongue.
When a dose is reached that's effective in reducing your allergic reaction (the maintenance dose), you'll need to continue with the injections or tablets for up to three years.
Immunotherapy should only be carried out under the close supervision of a specially trained doctor as there's a risk it may cause a serious allergic reaction.
Complications of allergic rhinitis
If you have allergic rhinitis, there's a risk you could develop further problems.
Ear infections often clear up within a couple of days, but paracetamol or ibuprofen can be used to help relieve fever and pain. Antibiotics may also be prescribed if the symptoms persist or are particularly severe.