Dr. Ameen, ENT Specialist in Kuala Lumpur

Chronic Rhinosinusitis: Causes and Risk Factors

Why Sinus Problems Become Chronic in Kuala Lumpur & the Klang Valley

One of the most common questions I hear in my ENT clinic is:
“Doctor, why do I keep getting sinus problems?”

It’s a fair question. After all, many patients have tried antibiotics, nasal sprays, allergy tablets—sometimes for years. Yet the symptoms keep coming back. The reason is simple but often misunderstood:

👉 Chronic rhinosinusitis (CRS) is not caused by just one thing.
It’s the result of multiple overlapping factors that keep the nasal and sinus lining inflamed over time.

Think of CRS like a leaking roof. You can keep mopping the floor, but unless you fix why it’s leaking, the problem never truly goes away.

Let’s explore the key causes and risk factors, especially those relevant to patients living in Kuala Lumpur and the Klang Valley.

---

1. Chronic Inflammation: The Root of the Problem

Modern ENT research makes one thing very clear:
CRS is primarily an inflammatory disease, not an infection.

While bacteria may play a role during flare-ups, the underlying issue is persistent inflammation of the nasal and sinus lining. This inflammation:

• Narrows sinus drainage pathways
• Traps mucus
• Creates a low-oxygen environment where symptoms persist

This concept is strongly supported by major ENT guidelines and explains why repeated antibiotics alone often fail.

---

2. Allergic Rhinitis (A Major Contributor in Malaysia)

Allergic rhinitis is one of the most important risk factors for CRS, especially in Malaysia.

Common triggers include:

• House dust mites
• Mould spores
• Pet dander
• Cockroach allergens
• Airborne particles

In Kuala Lumpur’s humid, indoor, air-conditioned environment, allergens thrive year-round. Chronic nasal allergy leads to:

• Swollen nasal lining
• Excess mucus production
• Blocked sinus drainage

Over time, this creates the perfect setup for chronic sinus inflammation.

If allergies are the spark, CRS is the fire that keeps burning.

---

3. Nasal Polyps and Type 2 Inflammation

In chronic rhinosinusitis with nasal polyps (CRSwNP), the immune system behaves differently.

This subtype is associated with:

• Eosinophilic inflammation
• Type 2 immune pathways
• Conditions such as asthma and aspirin sensitivity

Patients with nasal polyps often experience:

• Severe nasal blockage
• Loss of smell
• Poor response to standard medications

This explains why modern ENT management now includes targeted therapies and biologics in selected patients.

---

4. Structural Problems Inside the Nose

Sometimes, anatomy plays a role.

Examples include:

• Deviated nasal septum
• Narrow sinus openings
• Enlarged turbinates

These structural issues do not cause CRS on their own—but they increase the risk by preventing normal mucus clearance.

Imagine trying to drain water through a pipe that’s already bent and narrow. Even mild inflammation can tip the balance toward chronic disease.

---

5. Environmental Factors in Kuala Lumpur

Living in an urban environment brings its own risks.

Key contributors include:

• Air pollution
• Traffic-related particles
• Seasonal haze
• Construction dust

These irritants damage the nasal lining and impair its natural defence mechanisms. Over time, the nose becomes less efficient at clearing mucus and pathogens.

This is why CRS is significantly more common in urban populations compared to rural areas.

---

6. Recurrent or Inadequately Treated Infections

Repeated episodes of acute sinusitis—or incomplete treatment—can push inflammation into a chronic state.

However, it’s important to understand:
👉 CRS is not simply “infection that never cleared.”

Rather, infections often act as triggers in a system that’s already inflamed or anatomically vulnerable.

---

7. Smoking and Second-Hand Smoke

Smoking damages:

• Cilia (tiny hair-like structures that move mucus)
• Mucosal immunity
• Normal sinus ventilation

Even passive smoke exposure increases the risk of CRS and worsens treatment outcomes.

---

8. Medical Conditions That Increase Risk

Certain conditions are closely linked to CRS:

• Asthma
• Aspirin-exacerbated respiratory disease (AERD)
• Immune deficiencies
• Diabetes mellitus

These conditions alter immune responses and make chronic inflammation harder to control.

---

Why Understanding the Cause Matters

CRS is not a “one-treatment-fits-all” condition.

Successful long-term management depends on:

• Identifying the dominant drivers (allergy, polyps, anatomy, environment)
• Tailoring treatment accordingly
• Addressing inflammation—not just symptoms

This personalised approach is now the standard in modern ENT practice.

---