Allergies are a common feature of spring and summer as plants release high concentrations of pollen into the air. Many other substances, called allergens, can also cause allergic symptoms in the gastrointestinal tract, the respiratory system, the skin and the eyes. These reactions are part of a complex procedure carried out by the immune system in an effort to remove the foreign substance from the body, although most allergens are generally harmless. Some allergic reactions can be potentially dangerous, so you should be aware of any allergies you carry, especially to certain foods. If you have allergy symptoms, consult your doctor to discuss whether an allergy test and treatment are necessary.
Biological Response
Allergies are caused by an immune hypersensitivity to an otherwise harmless substance or environmental factor. When the body comes in contact with the allergen through inhalation, food or the skin, the immune system attacks it and tries to force it out of the body. The exact immune response will vary based on how the allergen enters the body. Inhaled substances will cause the release of histamine, which leads to a runny nose, coughing and sneezing. Food allergies are commonly accompanied by vomiting, stomach cramps and diarrhea. Skin allergies will cause a rash, itching, hives or blisters. Drug allergies are also possible and could affect the whole body.
Risk Factors and Development
The exact cause of allergy development is unclear, but several risk factors have been identified. According to the Mayo Clinic, a family history of allergies can increase your risk of having allergies. Children are also more likely to develop allergies than adults. Allergies that develop young sometimes lessen as the child grows. People with asthma -- or a family history of asthma -- have a higher chance of suffering from allergies as well. Having one type of allergy may also make you more susceptible to developing another.
Common Allergens
Common environmental allergens include animal dander, pollen and insect stings and bites. The smell of or contact with specific plants may also cause allergic reactions. Certain foods, especially shellfish, fish and nuts, may also be allergens. Some medications can produce allergies in certain people.
Anaphylaxus
Anaphylaxus, or anaphylactic shock, is an uncommon but potentially dangerous allergic reaction that affects the whole body. The anaphylactic reaction happens rapidly and can lead to the closure of airways and other severe symptoms.
