As soon as an allergen enters the body, an allergic reaction is stimulated in a person who is allergic to that particular allergen. Allergic reaction occurs when the immune system of the body fights against the invading allergen.
Causes of Allergic Reactions
When a foreign substance invades the human body, our immune system produces a protective antibody. Most important antibody that is produced in an allergic reaction is Immunoglobulin E (IgE). These antibodies are produced to fight against the invading foreign substance. But in this fight special cells are also injured without any fault. These special cells are called mast cells that release harmful substances in the blood thus giving rise to allergic reactions. These harmful substances produce itching, swelling and redness of the skin.
Causes of an allergic reaction
There are many different causes that can trigger an allergic reaction. In different persons there are varieties of causes for an allergic reaction. To fight against an allergen, white blood cells produce specific antibody to that antigen. Once the body is exposed to an antigen, reaction occurs between antigens and antibody. Antibody produced by white blood cells produces chemicals which have an effect on the local tissues and produces symptoms of the reaction.
Some of the important causes of allergic reaction are:
- Repeated exposure to poison ivy.
- Certain foods such as curd, milk, egg, wheat, and shell fish.
- Certain vaccines and medications such as NSAIDS or Sulpha containing drugs.
- Contact allergy results from contact of the skin with jewelry containing nickel.
- Many individuals are allergic to dust and pollen.
- Even exercise, emotions, hot or cold temperature, exposure to sun can also trigger allergic reaction in some individuals.
- Some allergies are hereditary and run in families such as hay fever, asthma, psoriasis, and eczema.
Symptoms of an allergic reaction
Sign and symptoms of an allergic reaction usually occur according to severity of the reaction and part of the body involved. Some of the important signs and symptoms occurring on the different parts of the body are:
- Redness itching, swelling, rash, blisters on the skin.
- Difficulty in breathing, tightness of chest, rapid pulse.
- Headache, confusion, swelling under the eyes of face.
- Redness, itching and watering from eyes.
- Abdominal pain, nausea, vomiting
Treatment of an allergic reaction
Remove allergen from the home. Removing allergen from home helps greatly in preventing allergic reaction.
After removing an allergen medication such as antihistamine can be given to suppress the allergic reaction.
For other difficulties such as breathing difficulties oxygen therapy may be given. Intravenous fluids may be administered in severe cases with low blood pressure.
References:
- Guidelines for care of Contact dermatitis (J Bourke, I Coulson, J English) BJD, Vol.145, No.6, December 2001 (p 877)- British Association of Dermatologists