Understanding Allergies: A Comprehensive Guide to Causes, Symptoms, Diagnosis, and New Treatment Hope

Allergies are an extremely common modern-day health issue, affecting hundreds of millions of people globally. Allergy sufferers often experience a significantly reduced quality of life: they may be unable to fully enjoy outdoor activities during spring blooms, may have to part with beloved pets, must carefully check food ingredients before eating, and could even face life-threatening anaphylactic shock from accidental exposure. Traditional treatments, such as antihistamines or nasal sprays, only provide temporary symptom relief without addressing the underlying cause—the immune system’s exaggerated response.

What is an Allergic Reaction?

An allergy is essentially a misdirection of the immune system. When the body mistakenly identifies harmless substances—such as pollen, dust mites, pet dander, or certain foods—as dangerous pathogens (like bacteria or viruses), it triggers a defense mechanism. This process involves the production of an antibody called Immunoglobulin E (IgE). IgE acts like an alarm, activating cells such as mast cells to release chemicals like histamine, which leads to classic allergy symptoms such as sneezing, runny nose, and itchy eyes. In short, an allergic reaction is an unnecessary “immune war.”

Symptoms of Allergic Reactions

Allergic symptoms vary widely in type and severity, depending on the allergen and the route of exposure:

Respiratory Allergies (e.g., Hay Fever, Dust Mite Allergy)

• Nose:Sneezing, runny nose (typically clear and thin discharge), nasal congestion, itchy nose.
• Eyes:Redness, itching, tearing, burning sensation (allergic conjunctivitis).
• Throat and Ears:Itchy throat, itchy palate, ear fullness.

Skin Allergies (e.g., Atopic Dermatitis, Hives)

• Skin:Rash, hives (wheals), eczema, intense itching.

Food Allergies

• Mouth:Tingling or swelling of the lips, tongue, or throat.
• Digestive Tract:Nausea, vomiting, abdominal pain, diarrhea.
• Skin:
• Severe Cases:May trigger a systemic allergic reaction.

Insect Sting Allergies (e.g., Bees, Wasps)

• Localized:Large areas of swelling, redness, and pain at the sting site.
• Systemic:May cause life-threatening anaphylaxis.

The Most Severe Reaction—Anaphylaxis

Anaphylaxis is a rapid-onset, whole-body, and potentially fatal allergic reaction. Symptoms include difficulty breathing, a sudden drop in blood pressure, dizziness, rapid heartbeat, swelling of the throat and tongue causing suffocation, confusion, and even loss of consciousness. This is a medical emergency requiring immediate use of an epinephrine auto-injector (EpiPen) and urgent medical care.

Causes of Allergic Reactions

Allergies typically result from an interaction between genetic and environmental factors:

• Genetic Factors:Children with one or both parents having allergies are at a significantly higher risk of developing allergies. This is known as an atopic
• Environmental Factors:
  • Hygiene Hypothesis:Overly clean modern environments reduce early childhood exposure to germs and microbes, potentially preventing the immune system from being properly “trained,” making it more prone to overreacting to harmless substances.
  • Allergen Exposure:Allergens present in living environments, such as dust mites, cockroaches, mold, and pollen.
  • Air Pollution:Pollutants can worsen allergy symptoms and increase sensitivity.
  • Dietary Habits:The timing and variety of early food introductions may also play a role.

Diagnostic Methods for Allergic Reactions

Effective treatment begins with accurately identifying the allergen. Doctors use the following methods for diagnosis:

Detailed Medical History:
A thorough discussion of your symptoms, their frequency, timing, location, and potential triggers is the first and most crucial step in diagnosis.

Skin Prick Test:
The most common test. A small amount of purified allergen extract is placed on the skin, and the surface is lightly pricked with a needle. If a raised, itchy bump (wheal) resembling a mosquito bite appears within 15-20 minutes, it indicates a possible allergy to that substance.

Blood Test (Specific IgE Test):
A blood sample is taken to measure the level of IgE antibodies produced in response to specific allergens. This method is suitable for patients who cannot undergo skin testing (e.g., due to severe skin conditions or antihistamine use).

Challenge Test:
Under strictly controlled medical supervision, the patient is exposed to a small amount of the suspected allergen (e.g., by inhalation or ingestion) to observe if a reaction occurs. Due to its higher risk, this test is only performed when necessary and under specialist care.

Allergy Treatment Methods and Process

Treatment can be divided into two main categories: symptom control and root-cause treatment.

Symptom-Control Medications:
Antihistamines, corticosteroid nasal sprays, and bronchodilators can quickly relieve discomfort but offer only temporary relief.

Root-Cause Treatment—Allergen Immunotherapy (Desensitization Therapy):
This is currently the only therapy that may fundamentally alter the course of allergic disease. It works by exposing the patient to gradually increasing doses of allergen extracts, starting from very low amounts, training the immune system to gradually “accept” the allergen instead of viewing it as a threat, thereby building immune tolerance. The process is akin to a long-term “reeducation of the immune system.” We will explore desensitization therapy in detail in our next article…

For assistance, please contact ENT Head and Neck Surgery Centre  (Tel: 3100 0555), where our ENT specialists will provide detailed diagnosis and formulate a treatment plan for you.

Source:

HK ENT Specialist Ltd.

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