Allergy is an immune reaction to a specific substance that’s usually part of the normal environment! The substance “Allergen” enters the body by inhalation, ingestion, touching or injection resulting in the allergy symptoms.
The immune system of the allergic patient produces large amounts of the antibody IgE. Which attacks mast cells in the skin, eye, mouth, stomach, lungs and other places. Breaking mast cells results in release the chemicals that results in allergy symptoms, such as Histamine. This process starts within half an hour of exposure to the allergen and can last for months if not avoided or treated.
The symptoms of allergy depend on the area affected. For example:
- Allergic rhinitis: nasal itch, runny nose, mucus, sneezing, congestion, cough, headache or bad mouth smell.
- Allergic conjunctivitis: itch, swelling, redness, watery eye.
- Allergic Asthma: cough, wheeze, phlegm, shortness of breath, difficulty in exercise, low oxygen.
- Skin Allergy: itch, skin rash like eczema, smooth skin rash like urticaria, lip swelling, face swelling or other.
- Gastric allergy: nausea, vomiting, pains, diarrhea or constipation
What is Anaphylaxis?
Sometimes allergy affects more than one place at one time! or results in suffocation because of laryngeal edema or fainting because of drop in blood pressure. This is life threatening and can result in death in 1%. This is called Anaphylaxis. Its occurs with food allergy, drug allergy and insect bites.
Is all allergy caused by IgE?
Not all allergy is caused by IgE. But its important to know if its caused by IgE because it indicates a higher risk of multiple & more likely to persist allergies. A higher IgE level predicts a more severe asthma, eczema or food allergy. As well, measuring the level repeatedly can help predict when the allergy will revolve or respond to treatment. Some treatment such as Allergy shots (Allergen Specific Immunotherapy) depend on the presence of specific IgE in treatment of asthma or rhinitis.