Allergies are common in almost every household. An allergy refers to any abnormal reaction to a harmful foreign substance. Substances like pollen, certain food substances and dust cause allergic reactions. They are known as allergens. In order to combat the reaction, the body’s immune system produces antibodies to fight the allergens. These antibodies release chemicals like histamine into the bloodstream which affect certain parts of the body like eyes, nose, lungs, and skin. Every time the body comes in contact with an allergen, the body has an allergic reaction.
There can be two reasons for an allergy -
• Genetic: If one parent has allergies the child has a 50% risk of having them. If both the parents are affected the child has a 70% risk
• Environment: The environment plays a role to make a person become susceptible to an allergy
A person with genetic predisposition to allergies may suffer from atopic dermatitis, atopic asthma or atopic rhinitis right from childhood. The initial symptoms seen are itching and red rashes and later development of runny nose and congestion. This may then progress into atopic asthma as they turn 5 or 6 years of age. They are very unlikely to outgrow these allergies and will have to continue to live with them throughout their life.
The Reaction
Three factors are responsible for this reaction-
• Allergen - this can include pollen, dust, medications, food, mold etc
• Mast cells - these cells present in the body are concentrated in the connective tissues of skin, tongue and lungs
• Immunoglobulin - it is a specific type of protein, an allergic antibody which fights the body against foreign invasion
When a person is exposed to an allergen (say pollen), the body produces large amounts of antibodies. The immunoglobulin causes the mast cells to release chemicals like histamine which causes itching, redness, spasm etc. If the allergen is airborne, the reaction can occur in the eyes, nose and lungs. If it is swallowed it can affect the mouth and the digestive tract. If sufficient chemicals are released through the blood stream then a reaction (hives) occurs throughout the body causing low blood pressure. A more severe reaction is called anaphylaxis which can lead to the death of the person.
Symptoms
They can be categorized as mild, moderate and severe.
Mild - symptoms like rash, watery eyes, congestion and itch are localized affecting only specific parts of the body.
Moderate - symptoms including hives, itchiness, swelling and also breathing difficulty can spread throughout the body
Severe - a severe reaction called anaphylaxis can cause the death of a person. The body’s reaction is sudden and affects the whole body. The initial symptoms may be itching of the eyes which slowly spread to swelling of the throat, stomach cramps, vomiting, hives, diarrhea and Angioedema. With very low blood pressure it can also cause dizziness.