Allergies are common diseases that affect the respiratory, gastrointestinal, cardiovascular, and dermatological systems. Allergic reactions are an abnormal reaction of the immune system to a substance that is otherwise harmless. The body’s normal reaction to contact with microorganisms or specific substances causes allergies. The immune system creates antibodies against these substances, which results in allergic reactions after repeated exposure. Each patient with allergies has different symptoms depending on what they react to and how their body responds. Symptoms usually result from physical contact with allergens but can also be airborne or occur when eating certain foods or ingesting medications. There are six types of allergy tests available today: skin prick test, patch tests, blood tests for IgE levels (ELISA), radioallergosorbent test (RAST), food challenges, and intradermal skin tests. The skin prick test or RAST are the most commonly used test
The word “allergy” comes from Greek words meaning “altered reactivity.” Allergic reactions come about when an individual has a hypersensitive immune system that responds to substances (called allergens) that would not normally cause such strong reactions in people who do not suffer from allergies. Allergies, like any other medical condition, are the result of the body’s inability to cope with something it comes into contact with regularly. For some people, this thing is pollen; for others, it might be a specific type of food or something more abstract such as emotions.
Where do allergies come from?
In very simple terms: your immune system is supposed to react in a certain way when a foreign substance enters your body and that reaction is different if that substance is harmless or harmful. Most of us have been exposed to substances considered harmless over time, so our immune system has learned how to deal with them and stay calm. In case you haven’t been exposed to this particular substance before though (let’s say because you never went outside), your immune system doesn’t know what to do and over-reacts, thinking the substance is harmful. This is your allergy.
In addition to this “classic” explanation though, there are several other theories out there regarding where allergies come from:
It’s all in our heads: Until recently this was a popular explanation as many people thought that allergies were psychosomatic and had nothing to do with the body. Allergens weren’t real; we just developed symptoms because we thought they were present or because we wanted them to be present (hypochondria).
This isn’t really supported by scientific studies though as scientists like Dr. Dennis Ownby, Professor of Pediatrics at Emory University School of Medicine and an expert on asthma and allergies, have heavily researched this theory for decades. He has found that there is no evidence that allergies are in our heads and that, among other things, IgE levels (an antibody associated with allergic responses) can be detected at high levels when people are exposed to an allergen even if they don’t develop any symptoms.
Allergies from the unborn child
It starts in the womb: Some scientists think it’s possible for a pregnant woman to pass certain food intolerances or allergies on to her unborn child. Consequently, children may start developing allergies before they’re even born simply because their mother couldn’t eat certain foods or was ill while she was pregnant. This could possibly explain why the number of children who suffer from food allergies seems to be significantly higher than what statistics say about adults having more of them.
Aside from food, some scientists think it’s possible for a pregnant woman to also pass on certain chemical intolerances or sensitivities to her child, which could lead him or her to develop an allergy.
This was more of a theory up until recently as there hasn’t been much evidence supporting this idea throughout history, but some studies seem to be showing that infants can actually develop allergies after being exposed to allergens through the placenta. This is very likely why doctors are seeing more and more cases of children developing food allergies later in life. It used to be considered unusual for someone who never had any kind of allergic reaction in their entire lives to start having problems with one specific type of food at the age of 40 50 60, but it’s becoming more and more common.
While the environment probably doesn’t have an impact on our genes, which are predetermined before we are born, some doctors do believe you can develop allergies through what is called ” epigenetics “. This is basically when your body changes how your genes are expressed or turn on/off certain genetic processes. These changes result in you being more susceptible to developing an allergy at a later point in time after being exposed to something new. This has been linked to some autoimmune diseases.