Allergic Rhinitis

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.

Common allergens

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.

Animals

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.

Work-related allergens

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.

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.

Allergy testing

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.

Further tests

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 computerised tomography (CT) scan – a scan that uses X-rays and a computer to create detailed images of the inside of the body

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.

Self-help

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

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

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.

Corticosteroids

If you have frequent or persistent symptoms and you have a nasal blockage or nasal polyps, your GP may recommend a nasal spray or drops containing 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.

Add-on treatments

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

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.

If you have allergic rhinitis, there's a risk you could develop further problems.

A blocked or runny nose can result in difficulty sleeping, drowsiness during the daytime, irritability and problems concentrating. Allergic rhinitis can also make symptoms of asthma worse.

The inflammation associated with allergic rhinitis can also sometimes lead to other conditions, such as nasal polyps, sinusitis and middle ear infections. These are described below.

Nasal polyps

Nasal polyps are swellings that grow in the lining inside your nose or sinuses, the small cavities above and behind your nose.

They're caused by inflammation of the membranes of the nose and sometimes develop as a result of rhinitis.

Nasal polyps are shaped like teardrops when they're growing and look like a grape on a stem when fully grown.

They vary in size and can be yellow, grey or pink. They can grow on their own or in clusters, and usually affect both nostrils.

If nasal polyps grow large enough, or in clusters, they can interfere with your breathing, reduce your sense of smell and block your sinuses, which can lead to sinusitis.

Small nasal polyps can be shrunk using steroid nasal sprays so they don't cause an obstruction in your nose. Large polyps may need to be surgically removed.

Read more about treating nasal polyps.

Sinusitis

Sinusitis is a common complication of rhinitis. It's where the sinuses become inflamed or infected.

The sinuses naturally produce mucus, which usually drains into your nose through small channels.

However, if the drainage channels are inflamed or blocked – for example, because of rhinitis or nasal polyps – the mucus can't drain away and it may become infected.

Common symptoms of sinusitis include:

• a blocked nose, making it difficult to breathe through your nose
• a runny nose
• mucus that drips from the back of your nose down your throat (post-nasal drip)
• a reduced sense of smell or taste
• a feeling of fullness, pressure or pain in the face 
• snoring
• obstructive sleep apnoea (OSA) – your airways become temporarily blocked while you're asleep, which can disturb your sleep

Over-the-counter painkillers, such as paracetamol, ibuprofen or aspirin, can be used to help reduce any pain and discomfort in your face.

However, these medications aren't suitable for everyone, so check the leaflet that comes with them before using them.

For example, children under the age of 16 shouldn't take aspirin, and ibuprofen isn't recommended for people with asthma or a history of stomach ulcers. Speak to your GP or pharmacist if you're unsure.

Antibiotics may also be recommended if your sinuses become infected with bacteria. If you have long-term (chronic) sinusitis, surgery may be needed to improve the drainage of your sinuses.

Read more about treating sinusitis.

Middle ear infections

Middle ear infections (otitis media) can also develop as a complication of nasal problems, including allergic rhinitis.

These infections can occur if rhinitis causes a problem with the Eustachian tube, which connects the back of the nose and middle ear, at the back of the nose.

If this tube doesn't function properly, fluid can build up in the middle ear behind the ear drum and can become infected.

There's also the possibility of infection at the back of the nose spreading to the ear through the Eustachian tube.

The main symptoms of a middle ear infection include:

• earache
• a high temperature (fever)
• being sick
• a lack of energy
• slight hearing loss

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.