The response of body to an invader substance is termed as allergic reaction. There can be various kinds of allergies such as dust, pollen, medicines, food, insect, viruses or bacterial allergy. The allergic reaction may be a small skin rash on one spot or all over the body. The reaction happened when immune system of the body is triggered by substances called antigen. The function of immune system is to protect the body from harmful substances like bacteria. When immune system sense kind of harmful substances, it is called hypersensitivity which is also known as allergic reaction.
Generally, allergic reaction is not dangerous to life but it may cause end of life in sever cases. One of extensive form of allergy is anaphylaxis which appears sudden and leads shock, problem in breathing or unconsciousness. It happened because of sudden dilation of large blood vessels. The blood pressure often drops under this condition, and consequently, may cause cardiac arrest or death.
The appearance of less harmful allergic reaction varies from involved body parts and intensively. The most common symptoms include skin redness, itching, swelling, blistering, weeping, crushing and rash. Other than the skin allergy, the symptoms may involve coughing, shortness of breath, swelling of face, eyelids swelling, lips swelling, tongue or throat swelling, sneezing, red or watery eyes, stomach pain, vomiting and diarrhea.
The cause of allergic reaction is a chemical process inside the body. The immune system contains white blood cells producing antibodies. When antigen exposes the body, it causes reaction. The people with certain problems such as allergic reaction in the past, asthma, chronic obstructive pulmonary disease, nasal polyps, frequent reaction to the nasal sinus, ear or reparatory tract and sensitive skin, are more likely to have fast allergic reaction.
The treatment of allergic reaction depends of allergy type. As a home care treatment, to avoid food allergy, a person should avoid the food that causes problem. For this purpose, prior knowledge of which food to avoid is necessary. To avoid the seasonal allergy, necessary precautions should be made at right time. Similarly, in case of skin allergy, the particular area should be treated with ice or cold water. Applying bags of frozen vegetables wrapped in a towel is also useful.