What is Allergy.?
We must know the concept of What is Allergy.?
An allergy is an overly sensitive (hypersensitive) disorder of immune system. If you are allergic, your body develops allergic immune response to substances that would not cause similar reactions in a non-allergic person.
These substances are called allergen or antigen. Antigens include pollen, dust mites, mold spores, pet dander, food, insect stings, and medicines.
What are the types of allergen exposure?
Allergens enter your body by four different routes:
1. Contact allergens enter your skin by touch. Example: poison ivy, latex gloves, jewellery
2. Ingestion. Example: food, drugs
3. Injection. Example: medications, bee sting
4. Inhalation. Example: pollents, dust mite, molds, animal danders.
What are symptoms of allergy?
Allergic rhinitis (“hay fever”) is the most common of the allergic disease. Symptoms result from the inflammation of the mucus membanes of nose nose, sinuses, and throat. Hay fever symptoms include
- Runny nose
- Stuffy nose
- Nasal itching (rubbing)
- Itchy ears and throat
- Post nasal drip (throat clearing)
Asthma is a breathing problem that results from the inflammation and spasm of the lung’s air passages (bronchial tubes). Common symptoms include:
- Shortness of breath
- Chest tightness
Allergic eyes (allergic conjunctivitis) is inflammation of the membranes that cover the surface of the eyeball and the inside of the eyelid. Symptoms of allergic eye include:
- Redness under the lids and of the eye overall
- Watery, itchy eyes
- Swelling of the membranes
Allergic eczema (atopic dermatitis) is an allergic rash due to inflammation of skin. Atopic eczema often occurs with hay fever and asthma. Symptoms include:
- Itching, redness, and or dryness of the skin
- Rash on the face, especially children
- Rash around the eyes, in the elbow creases, and behind the knees, especially in older children and adults (rash can be on the trunk of the body)
Hives (urticaria) are skin reactions that appear as itchy swellings on your skin. Typical hive symptoms are:
- Raised red welts (wheal and flare)
- Intense itching
Anaphylaxis or allergic shock
Allergic shock (anaphylaxis or anaphylactic shock) is a life-threatening allergic reaction that can affect a number of organs at the same time. This response typically occurs when the allergen is eaten (for example, foods) or injected (for example, a bee sting). Common symptoms of anaphylaxis include:
- Hives or reddish discoloration of the skin
- Nasal congestion
- Swelling of the throat
- Stomach pain, nausea, vomiting
- Shortness of breath, wheezing
- Low blood pressure or shock
Allergic shock is caused by dilated and “leaky” blood vessels (vasodilation), which result in a drop in blood pressure.
How is allergy diagnosed?
Allergy is diagnosed by history, physical examination, skin allergy test, allergy blood tests, and occasionally by deliberate allergen challenge. Allergy skin tests is the most common way to diagnose allergy.