What is an allergy?
Your immune system protects the body against foreign substances. But sometimes the system overreacts and treats harmless substances as a threat. A person without allergies would have no reaction to this harmless substance. However, a person with allergies will produce antibodies to attack this perceived threat.
This sets off a complex chain reaction within the body that causes the release of chemicals such as histamines. Unfortunately, histamines not only attack the threatening substance but also cause the typical symptoms of an allergy such as sneezing, itchy eyes, or a runny nose. Take hay fever, for example, the immune system overreacts to pollen and the release of histamine in the body causes hay fever symptoms like itchy eyes and sneezing.
What's the difference between seasonal and perennial rhinitis?
When you have an allergy, specific triggers or allergens will cause your body to react in a certain way. With hay fever, also known as rhinitis, an allergen that you breathe in causes an immune response in the lining of your nose. This can cause nasal passages to become swollen, inflamed, and irritated.
Symptoms occurring mainly in spring and summer are usually triggered by pollen from grasses, weeds and trees. This is called seasonal rhinitis and is commonly known as hay fever.
When symptoms occur year-round this is called perennial rhinitis, and they are usually triggered by house dust mites, animal dander or mould spores.
Typical allergy symptoms.....
Ranging from mild to severe, allergy symptoms, depending on the substance involved, can affect your airways, sinuses and nasal passages and skin. Allergic reactions can range from mild to severe. Hay fever, also called allergic rhinitis, can cause:
Itchy throat, inner ear or mouth
Red, itchy or watery eyes
Impaired sense of smell
Blocked, itchy or runny nose
A loss of concentration and generally feeling unwell
What is pollen?
Pollen is a small grain that is unique to the plants they come from. Most types of pollen have some degree of allergenicity, but some, such as pollen from grass, are particularly famous for inducing hay fever-like symptoms. Since pollen is so small and light, it can easily become airborne and travel in the wind.
Pets are also a common trigger for people's allergies. Cats, in particular, can cause allergies, but dogs and rabbit can also trigger the itching and sneezing commonly associated with pet allergies.
Dander is a mixture of small particles of fur, skin scales (like dandruff), and saliva).
In cats, for example, a particular protein found in cats' saliva causes an allergic reaction in many sufferers of airborne allergies. Because cats groom themselves so thoroughly, the saliva finds its way onto carpets, furniture, and other surfaces. For most people, it is not the fur itself that causes the allergy problem, it's dander.