Allergy is a disorder of the immune system often also referred to as atopy.
Allergic reactions occur to normally harmless environmental substances known as allergens; these reactions are acquired, predictable and rapid. Mind allergies can range from hay fever which causes runny nose and itchy eyes, to life-threatening anaphylactic reactions and 
potentially death. Allergies are also known to play an instrumental role in the development and severity of asthma.
Causes
Caused by harmless environment substances called allergens; Cereals containing gluten (i.e. wheat, rye, barley, oats, spelt, kamut or their hybridised strains). Crustaceans (e.g. crab, lobster, crayfish, shrimp, prawn, Eggs, Fish, Peanuts, Soybeans, Milk, Tree nuts (almonds, hazelnuts, walnuts, cashews, pecans, Brazils, pistachios, macadamia nuts, Queensland nuts).Celery and celeriac, Mustard, Sesame seeds, pollen, latex, or grass.
Who does it effect?
The factors which cause the onset of an allergy are placed into two categories; namely host and environmental factors. Host factors include heredity, sex, race, and age, but heredity being by far the most significant. However, there have been recent increases in the incidence of allergic disorders that cannot be explained by genetic factors alone. Four major environmental candidates are alterations in exposure to infectious diseases during early childhood, environmental pollution, allergen levels, and dietary changes
Pathology
An allergic reaction is divided into two phases, the first of which is the acute response that occurs also immediately after exposure to an allergen. This phase can either subside or progress into a “late phase reaction” which can substantially prolong the symptoms of a response, and result in tissue damage.
First thing that will happen is the allergen will enter your nose and interact with your mucous membrane. From there the antigen presenting cell will present the allergen to the first white blood cells (The T-cell) (T-cell is responsible for creating basically the memory of how to deal with unwanted microbes). The T-cell then presents the allergen to the next white blood cell the B-cell. (Which makes antibodies again foreign and unwanted antigens.) The B-cell then release an antibody known as IgE to fight the unknown allergen. The IgE attach themselves to the receptor sites of Mast and Basophils cells. They have granules which contain histamine and other allergy mediators instrumental in the allergic response. So on contact, the allergens will bind to the IgE antibodies which causes the release of histamine. The histamine will then bind to receptor sites along your blood vessels and increase permeability of the blood vessels resulting in synonyms such as stuffiness, sneezing, and teary eyes. Anti-histamine is medications which blocks the receptors sites and prevents they histamine from binding to the receptor sites and causing the synonyms.
On-set of Disease
The onset of allergies can occur any time during a person’s life. Severe allergies will often become apparent during a person’s early childhood but milder allergies can on set at any period in a person’s life; often brought on by environmental factors; environmental pollution, allergen levels, and dietary changes.
Symptoms
| Common Symptoms | |
| Nose | Swelling of the nasal mucos |
| Sinuses | Allergic sinusitis |
| Eyes | Redness and itching of the conjunctiva (allergic conjunctivitis) |
| Airways | Sneezing, coughing, wheezing, sometimes outright attacks of asthma, in severe cases the airway constricts due to swelling known as anaphylaxis |
| Ears | Feeling of fullness, possibly pain, and impaired hearing |
| Skin | Rashes, such as eczema and hives |
| Gastrointestinal tract | Abdominal pain, bloating, vomiting, diarrhea |
Diagnosis
Two Types of Diagnosis tools used to identify allergic reactions: Skin testing and Blood testing. The testing will be based of symptoms described to the doctor and severity of which.
Skin Testing
For assessing the presence of allergen-specific IgE antibodies which usually cause (skin rashes, hives, itchy eyes, and nasal swelling) Skin 
testing is used because it is more sensitive and specific, simpler to use, and less expensive. They will lay a grid out on your arm or back and make a series of tiny punctures in which they will place the small amount of the suspected allergen. If the patient is allergic to the substance, then a visible inflammatory reaction will usually occur within 30 minutes. This response will range from slight reddening of the skin to a full-blown hive. Interpretation of the results of the skin prick test is normally done by allergists on a scale of severity, with +/- meaning borderline reactivity, and 4+ being a large reaction.
Blood Testing
For more severe allergies which can cause: vomiting, diarrhea and closing of the airway a blood test is used. This kind of testing measures a “total IgE level” and is determined through the use of radiometric. They use anti-IgE antibodies which the labelled with radioactive isotopes for quantifying the levels of IgE antibody in the blood; when a suspect allergen extract is introduced into the blood stream.
Treatment
There have been enormous improvements in the medical treatments used to treat allergic conditions. With respect to anaphylaxis and hypersensitivity reactions to foods, drugs, and insects and in allergic skin diseases, advances have included the identification of food proteins to which IgE binding is associated with severe reactions and development of low-allergen foods.
To block the action of allergic mediators, or to prevent activation of cells and degranulation processes. These include antihistamines such as Loratadine (Claritin), which block the histamine receptors along with cortisone, which reduce inflammations, and Epinephrine (adrenaline) which suppresses the immune system and release of IgE antibodies, making it the main choice to air swelling or anaphylaxis.
There is very little a person can do to prevent allergies, the only option being avoidance of the allergen from either contact or ingestion. To alleviate symptoms (such as sinus inflammation, sneezing, itchy eyes) from allergens which in most cases can’t be avoided (like grass or pollen) They use antihistamines such as Claritin.
With people who suffer from severe allergies they will often carry a medical alert bracelet or necklace, which states their conditions and for those who suffer from anaphylaxis, they carry an EpiPen containing epinephrine which reduces the swelling of their airway.
Prevention program are in place by many companies and institutions. A lot of companies now carry a 100% peanut free on their candy bars, some elementary school prohibit certain foods from being brought to school where severe allergies are known. Anytime you receive a food order from schools or restaurants they ask you to identify and known allergies. Also largely potential allergies such as egg, peanuts and latex are always clearly marked on packages which contain them.
Future Cures
There are many allergy foundations throughout the world, the largest of which is the Asthma and Allergy Foundation of America (AAFA), which is a non-profit organization dedicated to finding a cure for and controlling asthma, food allergies, nasal allergies and other allergic diseases. AAFA’s mission is also to educate the public about these diseases.
As for research, scientists are still working on identifying the exact factors which causes allergies and how to counteract them.
Scientists are doing research Mount Sinai Hospital are looking into the possibility of introduction to of certain allergens such as peanut before the age of two or three will help prevent allergies from arising. Many people, not scientists believe feeding babies food such as peanut butter, eggs and fish should be withheld until their immune system has fully developed at age 3.
Also Jonathan Brostoff, Professor of Allergy at King’s College London, is working on vaccines that could potentially create antibodies that would become proactive during the introduction of allergen into the body and cellular response for the allergen.
