Question 1

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, pollen, pepper, a virus-inflamed membrane — and signal the brainstem. A coordinated response follows: a deep breath in, closure of the glottis, contraction of chest and abdominal muscles to build pressure, then explosive release through the nose and mouth. Air leaves at considerable speed, carrying the irritant with it.

**It is involuntary and hard to suppress**, which is characteristic of protective reflexes — the same category as coughing and blinking.

**The sunlight sneeze** affects an estimated 18–35% of people and has a proper name: the **photic sneeze reflex**, sometimes given the deliberately contrived acronym **ACHOO** (Autosomal Dominant Compelling Helio-Ophthalmic Outburst).

**It is inherited.** The pattern is autosomal dominant, meaning one copy from either parent is enough, and roughly half the children of an affected parent will have it. Genome-wide studies have identified associated variants.

**The leading explanation is crossed wiring.** The **trigeminal nerve** carries sensation from the face and nasal passages, and it runs very close to the **optic nerve**. The theory is that a sudden strong visual stimulus produces signalling that is partly misinterpreted as nasal irritation — the brain receives what looks like a nose signal and responds with a sneeze. It remains a hypothesis rather than a settled mechanism.

**It is usually harmless** but occasionally matters practically: emerging from a tunnel while driving, or a pilot at a critical moment, and it has been discussed in aviation medicine.

**Never suppress a sneeze by pinching your nose and closing your mouth.** Case reports document serious injuries from the redirected pressure, including ruptured eardrums and, rarely, a torn throat.

Question 2

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,

Question 3

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 4

What is sleep apnoea, and why does it matter?

Accepted Answer

Repeated interruption of breathing during sleep, lasting seconds at a time and occurring anywhere from a few to hundreds of times a night — and it matters because the person affected is usually

Question 5

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 6

Why does a cough linger for weeks after you feel better?

Accepted Answer

Because the infection clearing and the airways recovering are separate processes, and the second takes considerably longer. What a cough is. A protective reflex clearing the airways, triggered by

Question 7

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.

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