How Do Allergies Develop?

Allergies affect more than 60 million people in the United States. One in four, suffers from allergies in the United States. The annual spending on allergies is more than 18 billion dollars. They are more than just a seasonal nuisance. About 56% people suffering from allergies have symptoms throughout the year. It is the 6th leading chronic illness in America. Hence, it becomes imperative to understand

how do allergies develop


Allergies are basically an auto immune response of the body. The body reacts to certain otherwise harmless substances in the environment. These proteins or irritants trigger the immune system to get the defensive gear of the body switched on. The defensive responses put forth by the body are manifested as adverse physical reactions, generally termed, as allergies.

There are several theories why some individuals have a hypersensitive immune system and have allergies. Why that is the body fights harmless substances like cat dander or pollen? This article is intended to explain the mechanism behind teh development of allergies.

Allergies are often developed in childhood. Most allergies appear before 20. However, they can appear at any age, young or old. It is very hard to outgrow allergies. The non appearance of symptoms may encourage one to think that they are cured from it. But the truth is the sensitivities lie latent and can reappear with the slightest trigger.

Are allergies genetic?

Allergies are not inherited. But the risks of having them greatly increases if any family member has it. The risk of being allergic increases by 66% if both parents have them. If one parent has it, then the risk increases by 60%. If your parents have been allergy sufferers, chances are you are going to suffer from it too.

How do allergies develop?

The Hygiene Hypothesis theory

The development of allergies is often dependant on what your exposed to as a child. The theory Hygiene Hypothesis propounded by scientist, David P. Strachan was the first attempt to explain the thought. This theory states that childhood exposure to infectious agents, parasites, symbiotic microorganisms ( the good gut bacteria or probiotics) may help thwart allergic diseases later on. Early exposure will allow the immune system to identify the irritants and allergens well. The immunological tolerance will be induced gradually over the years. Dr. Strachan in his article in the British Medical Journal, had mentioned his observation that eczema and hay fever, both allergic diseases, were less common in children from larger families. The idea was that, children from larger families would be exposed to more infection causing triggers from their siblings than those from small families.

The steps involved in the development of allergies are as follows:


The first step would be the exposure to the allergen. The common allergens to cause allergies are pollen, dust, molds, food, animal dander, drugs, insect venoms etc.


In response to the stimuli of exposure, the immune system gets prepared to respond. The body perceives the otherwise harmless allergens as a threat and produces antibodies to deal with them. These antibodies are called the Immunoglobulin E antibodies(IgE). They are a type of protein produced by the plasma and lymph cells in the body. They react with the allergen and causes them to bind with the mast cells in the body. The mast cells are found in the gut, pharynx, skin and mucus membranes. These cells release a chemical known as Histamine. Each type of IgE is produced to react to particular type of allergen. They make the immune system to destroy the allergen. Once made, the antibody stays in the body. They cause the same type of allergic response everytime they come in contact with the said allergen.

The above article gives a clear picture as to

how do allergies develop

. It is important to find a balance between hygiene consciousness and exposure to environmental irritants to be able to lead a life with minimum amount of allergies.

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