Why do we have Allergies?

Our immune system is the first line of defense against any invader. If a bacteria, virus or any allergen tries to enter our body then our immune system will react against that allergen/ substance. Our system is an intelligent system that is able to distinguish between harmful and harmless substances. But in some cases, our immune system will react against the harmless substances like pollen, egg, cat dander etc. This reaction is allergy.  Some individual may have allergy and some have not. It is the genetic make up of an individual which is responsible for these kind of reaction.

An atopic individual is a person who has inherited tendency to develop allergic reaction. Atopy is the genetic (inherited) tendency to develop allergic diseases. These substances are known as allergens and are found in dust mites, pollen, pets, insects, moulds, foods and certain medicines.

When atopic people are exposed to allergens they can develop an immune reaction that leads to allergic inflammation which is manifested by redness and swelling.

This can then cause symptoms in several organ systems including:

• Nose and/or Eyes – hay fever (allergic rhinitis/conjunctivitis)
• Skin – eczema, hives (urticaria)
• Lungs – asthma

The most common causes of allergic reactions  are:

• Dust mites- Major allergen worldwide. Microscopic. Feeds human skin scales and debris. Acts as perennial allergen.
• Pollen like grass pollen or tree pollen. Allergenic pollen generally wind borne from grasses, trees etc. Mainly cause Allergic Rhinitis. Rainfall can influence abundance.
• Foods such as peanuts, cow’s milk, soy, seafood and eggs
• Cats and other furry or hairy animals such as dogs, horses, rabbits and guinea pigs
• Cockroach. Two species American and German. Live in warm and humid places.
• Insect stings and tick bites
• Moulds: Cause both seasonal and perennial symptoms. Grow in warm, humid environment. Alternaria, Aspergillus important.
• Certain medicines like Antibiotics, such as penicillin, Aspirin and non-steroidal anti-inflammatory medications, such as Ibuprofen, Anticonvulsants, Monoclonal antibody therapy, Chemotherapy drugs.

A family history of allergy is a risk factor for allergy in offspring.