Causes of Allergic Rhinitis

What Causes Allergic Rhinitis?

Allergic Rhinitis is in most cases caused by an over-sensitive immune system reacting to particles such as dust, or pollen, as though they were harmful to the body. When the body senses that it is under attack from these allergens, it produces antibodies to try and fight off the aggressor. These antibodies are made up of proteins contained within the blood that are usually used to fight of viruses or infection.

Allergic reactions do not happen on the first occasion that a person comes into contact with the particles – the immune system needs to recognise the particle and memorise it as an allergen before it reacts by making the antibodies, referred to immunoglobins, to fight it. This process is called sensitisation, and the time this takes can vary between days, or even years.

Once a person is sensitised, any amount – even a tiny, single particle of the allergen, can trigger an allergic reaction; in many cases this involves the body releasing histamine and this is responsible for a lot of the symptoms of allergic rhinitis such as the swelling of the mucus membrane and the subsequent production of excessive mucus, blocking the airways and causing a runny nose, itchy eyes etc.

Common Allergens

While humans have the capacity to become sensitised to a wide range of different allergens, the most common are as follows:

Pollen from trees, grasses and flowers – one of the most common forms of allergic rhinitis is Hay Fever; when people become allergic to the tiny particles of pollen released by plants. In most cases plants pollenate during spring and summer with different species producing pollen at different periods within this time frame.

Dust mites – no matter how clean your house or work environment might be, it is still very likely that it is host to a population of house dust mites. These tiny creatures live in our mattresses, carpets, bed-linen, pillows and any other soft furnishings. It is not the mites themselves that cause the problems, but a chemical that is found in their excrement that causes the allergic reaction.

Animals – lots of people are allergic to cats and dogs, but it is not actually the animal that causes the problem, not even their fur or feathers, but the flakes of dead skin, urine and faeces (known as dander) in which the allergens are present. Any animal that has fur or feathers can become a problem for allergic rhinitis sufferers.

Work-related allergens – depending on the type of work you do, there is a range of common allergens that can be found in work environments: wood dust from sawmills and carpentry environments, flour dust in bakeries, even the latex dust within protective gloves that are provided to protect the wearer from other risks.

Other risk factors

It is yet to be understood why some people become sensitised to certain allergens whereas others remain unaffected, but there are some common factors that should be recognised:

Family history – if your family has a history of suffering from allergies it could increase your likelihood of developing them yourself.

Growing up with smokers – growing up in an environment filled with cigarette smoke can increase the chances of developing allergies early or later on in life.

Exposure to pets – unusually this can work both ways: it can increase the likelihood of someone becoming allergic, but it can also reduce the risk by assisting the body to build up a tolerance.