How the body’s immune system responds to harmless substances is what is referred to as allergy. Different people are allergic to different things.
An allergy is the response of the body's immune system to normally harmless substances, such as pollens, foods, and house dust mite. Whilst in most people these substances (allergens) pose no problem, in allergic individuals their immune system identifies them as a’ threat’ and produces an inappropriate response.
Allergies do not occur all at once. In short, a person cannot be exposed to a substance and become allergic to it instantly. Exposure to such a substance the first time is when the body develops protection against the invading substance.
Allergies usually do not occur at the first exposure. When a person is exposed to an allergen for the first time, the body develops molecules called antibodies against the invading proteins. This is called an immune response.
When exposed to the allergen again the immune system produces large amounts of antibodies that lead to break down of mast cells that contain chemicals like histamine. This leads to the features of allergies.
This process is known as sensitization. Sensitization may take days to years. Sometimes sensitization develops as the person affected shows symptoms but never fully develops the allergy to the allergen.
Usually there are symptoms that accompany an allergy. It is therefore vital to know the signs or symptoms so as to be able to tell if a person is allergic to a substance.
The part of the body the allergen touches affects what symptoms you develop. For example:
Allergens that you breathe in often cause a stuffy nose, itchy nose and throat, mucus, cough, and wheezing.
Allergens that touch the eyes may cause itchy, watery, red, swollen eyes.
Eating something you are allergic to can cause nausea, vomiting, abdominal pain, cramping, diarrhea, or a severe, life-threatening reaction.
Allergens that touch the skin can cause a skin rash, hives, itching, blisters, or skin peeling.
Drug allergies usually involve the whole body and can lead to a variety of symptoms.
Home treatment can be done for minor allergy symptoms but if symptoms persist there is need to seek medical health. Some allergic reactions are quite life threatening.
Minor allergic reactions can be safely treated at home. Over-the-counter antihistamines and decongestants can ease congestion and breathing problems. These medications are generally available as tablets, eye drops, and nasal sprays.
Swelling, redness, and itching may be reduced with the use of ice and topical creams that contain corticosteroids. Acetaminophen can lessen pain. If symptoms persist, your doctor can prescribe more powerful medications.