What Causes Allergies? How do allergies evolve?
Allergies can make your day-to-day existence miserable. A stroll in the park, a yarn ball toss with Fluffy, a seafood dinner, or just something as minute as a nut can easily bring about such irritating complaints as itchy eyes, a runny nose, sneezing, or a skin rash.
But, frequently a person’s allergic reactions can escalate from merely irritating to serious and even life-threatening as the air passageway begins to constrict and inhaling and exhaling becomes labored. This development of symptoms can frequently bring about a state of acute anxiety plus a trip to the emergency room.
Allergies can, indeed, turn into a very serious hindrance and cause you to feel unable to take part in everyday activities. In fact, if you are one of the many sufferers who have allergic reactions, it might even seem to you that, every once in awhile, your environment is a pretty antagonistic place and that the world around you is, actually, out to get you!
You might question how it is that other human beings seem to be so susceptible to the exact same environmental stresses that send your body into overwhelm. Other people appear either unaware of or plainly`totally unresponsive to the would-be irritants that lurk at every turn, while your body reacts, or rather overreacts, to them. Why you? It’s a valid question. The answer is that some men and women, such as yourself, have a hyperactive immune system that more or less “goes into a frenzy” whenever you encounter routine substances particularly pollen, dander, shellfish, or nuts.
How do allergies evolve?
Allergic diseases and autoimmune diseases occur because the immune system is conditioned to respond to inappropriate targets. If it attacks the body, it is an autoimmune disease and if it attacks a harmless environmental protein, it is an allergy. In the case of allergy, pollen seasons can produce a huge immune response because of the significant amount of exposure. Interestingly, these problems are much more common in rich, industrialized countries. A theory about why this happens is called the hygiene hypothesis.
In population studies, the prevalence of allergy and asthma is low in developing countries that do not have the advanced sanitary facilities in rich countries. This lack of sanitation leads to early exposure to parasites and other microbes that are likely to be similar to what people have experienced during centuries of evolution. Because our immune system has developed over a long period of time under constant exposure to microbes, the potential of the system is still active, but no longer a suitable target if those microbes are removed.
Studies have shown that exposure of the immune system to parasites and other microbes allows the system to develop the regulatory mechanisms that keep it focused and under control. In the normal development of childhood, it is assumed that the immune system shifts from the anti-parasitic inflammatory pathway that predominates at birth to the antibacterial non-inflammatory pathway. In clean environments that do not have exposure to parasites, this transition can not occur and the child who is prone to allergy begins to develop an inflammatory immune response against harmless environmental proteins.
This is not to romanticize unhygienic conditions, of course. Although the rates of allergy and asthma are low in developing countries, the figures for preventable diseases are much higher. This suggests that biological systems require a balance, where overcorrection of one problem has unforeseen negative consequences.