Question 1

What actually happens in an allergic reaction?

Accepted Answer

The immune system misidentifies a harmless substance as a threat and mounts a defence against it — and the damage comes entirely from **your own response**, not from the substance itself.

**The mechanism, in two phases:**

**Sensitisation.** On first exposure, the immune system produces **IgE antibodies** specific to the allergen. These attach to **mast cells** in tissue and basophils in blood. Nothing happens yet — first exposure is silent, which is why a reaction can appear to come from nowhere after years of eating something.

**Reaction.** On later exposure, the allergen binds to those antibodies, cross-linking them and triggering the mast cells to **degranulate** — releasing **histamine** and other mediators in seconds. Histamine dilates blood vessels, makes them leaky, contracts smooth muscle and stimulates nerve endings. Everything you experience follows from that: swelling, redness, itching, running nose and eyes, wheezing, and gut cramping.

**A late-phase reaction** frequently follows hours later as other immune cells arrive, which is why symptoms can return after apparently settling — and why observation after a severe reaction matters.

**Anaphylaxis** is the same process happening systemically. Widespread vessel dilation and leakage cause **blood pressure to collapse**, while airway swelling and bronchospasm obstruct breathing. It can develop within minutes.

**The signs requiring immediate action:** difficulty breathing, wheeze, throat tightness or swelling, hoarse voice, feeling faint, collapse, or a sudden sense of impending doom.

**Adrenaline is the treatment**, given by auto-injector into the outer thigh. It reverses vessel dilation, raises blood pressure, and opens the airways. **Antihistamines do not treat anaphylaxis.** Call emergency services, lie the person flat with legs raised — **not sitting or standing, which can be fatal** — and be ready to give a second dose.

**Why allergies are rising** is not settled; reduced early microbial exposure, changes in diet and skin barrier function are all proposed.

**Intolerance is different** — it does not involve the immune system and is not life-threatening.

General information, not medical advice.

Question 2

How to tell if it's a cold or allergies?

Accepted Answer

Identifying whether you have a cold or allergies involves recognizing symptom differences, such as onset, duration, and specific signs like fever or itchy eyes.

Question 3

How can I tell if my symptoms are due to COVID-19 or allergies?

Accepted Answer

Distinguishing between COVID-19 and allergies involves understanding symptom onset, duration, and specific signs like fever or loss of taste. Consult a healthcare provider for accurate diagnosis.

Question 4

How can I tell if I have allergies or a cold?

Accepted Answer

To tell if you have allergies or a cold, note symptom duration, nasal discharge, itching, fever presence, and onset speed. These factors help differentiate the two.

Question 5

Why do cuts itch as they heal?

Accepted Answer

Itching during healing is usually a sign the repair process is active, and several mechanisms contribute at once. Histamine release. During the inflammatory and proliferative phases, immune cells

Question 6

What is eczema, and what actually helps?

Accepted Answer

A condition in which the skin's barrier function is impaired, allowing moisture out and irritants and allergens in, producing inflammation, itching and dryness — and understanding it as a barrier

Question 7

Why do we sneeze, and why do some people sneeze in sunlight?

Accepted Answer

A sneeze is a protective reflex that expels irritants from the nasal passages using a sudden, forceful burst of air. The sequence. Sensory nerve endings in the nasal lining detect an irritant — dust,

Related Questions