When the Immune System “Gets It Wrong”

Allergy is one of the most common health conditions in the modern world, affecting millions of people of all ages. But what exactly happens in our body when an allergic reaction occurs? Simply put, an allergy is the result of the immune system “getting it wrong.” The immune system is the body’s natural defence mechanism against potentially harmful invaders such as viruses and bacteria. In people with allergies, however, the immune system mistakenly identifies an otherwise harmless substance—such as pollen, house dust mites, or a food—as a “threat” and launches an exaggerated immune response in an attempt to neutralise it. The substances that trigger these reactions are called allergens.

How Does an Allergic Reaction Develop?

When a person who is prone to allergies comes into contact with an allergen, their immune system produces specific antibodies known as Immunoglobulin E (IgE). This process is called sensitisation. Upon subsequent exposure to the same allergen, the IgE antibodies that have already been produced recognise it rapidly and signal specialised cells in the body to release chemical substances. One of the most important of these is histamine, which is responsible for many familiar allergy symptoms, including redness, itching, swelling (oedema), and increased mucus production.

What Are the Most Common Allergens?

Allergens can be divided into several categories depending on how a person is exposed to them:

• Airborne allergens: Pollen from trees, grasses and weeds, house dust mites, moulds, and pet dander.
• Food allergens: Milk, eggs, nuts, fish, shellfish, wheat, and soy.
• Medications: Antibiotics (e.g. penicillin), non-steroidal anti-inflammatory drugs (NSAIDs), and others.
• Insect stings: Venom from bees and wasps.
• Contact allergens: Nickel, fragrances, and chemical ingredients found in cosmetics.

What Are the Symptoms of an Allergic Reaction?

Symptoms vary depending on the part of the body affected by the allergic reaction:

• Upper respiratory tract and eyes: Sneezing, runny nose, nasal congestion, and itching of the nose and eyes (Allergic Rhinitis / Allergic Conjunctivitis).
• Lungs: Coughing, wheezing, and shortness of breath (Allergic Asthma).
• Skin: Redness and intensely itchy rashes (Urticaria/Hives), as well as dryness and inflammation (Atopic Dermatitis / Eczema).
• Digestive system: Abdominal pain, nausea, vomiting, and diarrhoea, particularly in food allergies.
• Anaphylaxis: The most severe and potentially life-threatening form of allergic reaction. It can affect several organ systems at the same time and requires immediate medical attention.

Why Do We Develop Allergies?

Allergies develop as a result of a combination of factors, with genetic predisposition (atopy) being one of the most important. In simple terms, when one or both parents have allergies, the likelihood of their child developing an allergic condition is increased.

Environmental factors also play an important role. These include air pollution, aspects of the modern lifestyle such as increased consumption of processed foods, antibiotic exposure early in life, and reduced exposure to a diverse range of microorganisms during childhood, particularly as an increasing proportion of the population lives in large urban environments. These factors may influence the development and regulation of the immune system and contribute to the development of allergic diseases.

How Are Allergies Treated?

Maintaining the allergic patient’s quality of life is a primary goal of treatment. Modern Allergology aims to achieve effective symptom control through a comprehensive treatment plan based on three main approaches.

The first is allergen avoidance. Once the responsible allergens have been identified through appropriate diagnostic testing, specific measures can be taken to reduce exposure to them.

The second is medication, which may include antihistamines, corticosteroid nasal sprays, inhaled medications, or other treatments used to control and relieve allergic symptoms.

Finally, Allergen Immunotherapy (allergy shots / drops / tablets) is the only disease-modifying treatment that targets the underlying allergic response rather than simply relieving symptoms. By gradually exposing the immune system to controlled amounts of the responsible allergen, immunotherapy helps the body develop tolerance to it. This can provide significant and long-lasting improvement in allergic symptoms and reduce the need for medication.

In conclusion, if you suspect that you or a member of your family may be experiencing allergic symptoms, they should not be ignored. An appropriate allergy assessment, including specialised skin tests and/or blood tests, can provide clear answers, identify the responsible allergens, and guide the selection of the most appropriate treatment.

For more information or to schedule an allergy assessment, please contact our clinic.