Dr Ameen

Article written by Dr Ameen, ENT Specialist Kuala Lumpur

Foul smell perception, known medically as cacosmia, occurs when you detect unpleasant odours that others cannot smell or when normal scents appear distorted and putrid. This condition typically stems from sinus infections, nasal polyps, dental problems, or neurological issues affecting the olfactory system. Understanding the underlying cause is essential for effective treatment.

What Exactly Is Cacosmia?

Cacosmia represents a specific type of olfactory dysfunction where patients experience persistent foul or unpleasant smells. Unlike phantosmia, which involves smelling odours that do not exist, cacosmia often relates to actual pathological processes in the nasal cavity or sinuses. The distinction matters because treatment approaches differ significantly.

In my practice here in Kuala Lumpur, I encounter patients who describe this smell as rotten, sewage-like, or reminiscent of burning rubber. They feel embarrassed, anxious, and frankly, quite distressed. It affects their appetite, social interactions, and overall quality of life. The humid tropical climate we experience here can exacerbate underlying sinus conditions, making cacosmia more prevalent among our population.

Common Causes Behind Foul Smell Perception

Recent publications in JAMA Otolaryngology and The Laryngoscope highlight several primary etiologies:

Sinonasal Conditions

• Chronic rhinosinusitis with or without nasal polyps
• Acute bacterial sinus infections
• Fungal sinusitis (particularly relevant in our humid climate)
• Atrophic rhinitis (ozena)
• Foreign bodies in the nasal cavity

Dental and Oral Sources

• Periodontal disease
• Dental abscesses
• Poor oral hygiene
• Tonsil stones (tonsilloliths)

Neurological Factors

• Post-viral olfactory dysfunction
• Head trauma affecting olfactory nerves
• Neurodegenerative conditions (Parkinson’s, Alzheimer’s)
• Temporal lobe seizures

Other Contributors

• Medications causing taste and smell disturbances
• Nasal tumours (rare but serious)
• Gastroesophageal reflux disease

I’ve noticed that many patients in Malaysia delay seeking help, assuming the smell will resolve on its own. Sometimes it does, but often it signals an underlying issue requiring intervention.

Recognising the Symptoms

Patients with cacosmia typically report:

• Persistent foul odour perception (unilateral or bilateral)
• Smell distortion when eating or drinking
• Reduced sense of smell (hyposmia) or complete loss (anosmia)
• Nasal congestion or discharge
• Facial pain or pressure
• Post-nasal drip
• Bad breath that others may notice

The European Archives of Oto-Rhino-Laryngology notes that unilateral foul smell particularly warrants investigation to rule out foreign bodies or neoplasms.

Evidence-Based Diagnostic Approach

Diagnosis requires thorough evaluation including:

Clinical Examination

• Detailed nasal endoscopy
• Assessment of oral cavity and dentition
• Neurological examination when indicated

Imaging Studies

• CT scan of paranasal sinuses (gold standard for sinus pathology)
• MRI brain if neurological cause suspected

Olfactory Testing

• Standardised smell identification tests
• Threshold testing

Laboratory Work

• Allergy testing when allergic rhinitis suspected
• Microbial cultures from sinus secretions

Treatment Strategies That Work

Management depends entirely on identifying and addressing the root cause:

For Sinonasal Disease

• Saline nasal irrigations (twice daily minimum)
• Intranasal corticosteroid sprays
• Antibiotics for acute bacterial infections
• Functional endoscopic sinus surgery (FESS) for refractory cases
• Polypectomy for nasal polyps

Addressing Dental Issues

• Professional dental cleaning by qualified dentist
• Treatment of dental infections
• Extraction of non-salvageable teeth

Managing Neurological Causes

• Olfactory training therapy
• Medication adjustment if drug-induced
• Referral to neurology when appropriate

Supportive Measures

• Zinc supplementation (evidence mixed but worth trying)
• Alpha-lipoic acid (anti-oxidants)
• Avoidance of nasal irritants

From my experience at hospitals across KL, patients who commit to consistent nasal irrigation and follow-up care see remarkable improvement. The International Forum of Allergy & Rhinology emphasises that treating underlying inflammation proves more effective than symptomatic management alone.

Prevention Tips for Kuala Lumpur Residents

Our environment presents unique challenges:

• Manage allergies proactively during haze season
• Maintain excellent oral hygiene
• Stay hydrated in our hot climate
• Use air purifiers indoors when air quality poor
• Seek early treatment for sinus infections
• Regular dental check-ups

Frequently Asked Questions

Can cacosmia resolve on its own? Sometimes, particularly if caused by acute viral infections or temporary inflammation. However, persistent symptoms beyond two weeks require medical evaluation to identify and treat underlying causes.

Is foul smell perception a sign of brain tumour? While extremely rare, certain brain tumours can affect olfactory pathways. Most cases stem from benign sinus or dental issues. Unilateral symptoms with neurological signs warrant imaging studies.

How long does treatment take to work? Acute infections may improve within days of antibiotics. Chronic sinusitis requires weeks to months of consistent treatment. Post-surgical recovery varies but most patients notice improvement within 4-6 weeks.

Can stress cause cacosmia? Stress does not directly cause cacosmia but can heighten awareness of symptoms and worsen perception. Anxiety about the smell often amplifies distress, creating a vicious cycle.

Conclusion

Living with persistent foul smell perception feels isolating and frustrating. You might worry others notice it, avoid close conversations, or lose enjoyment in food. The good news: most causes are treatable. Whether it’s chronic sinusitis requiring medical management, dental issues needing attention, or something requiring surgical intervention, proper diagnosis changes everything.

Don’t suffer in silence hoping it disappears. Modern ENT care offers effective solutions, and early intervention prevents complications.

When Should You See an ENT Specialist?

If your symptoms persist, worsen, or are affecting your daily life, it’s best to get a proper ENT assessment. Early evaluation can help identify the exact cause and prevent complications. You can consult Dr Ameen for a detailed evaluation and personalised treatment plan. Appointments can be arranged directly with the clinic for convenience.

About the Author

Dr. Ameen is an ENT Specialist and Surgeon based in Kuala Lumpur. He earned his medical degree (MB BCh BAO, Hons) in Ireland and completed his Master of Otorhinolaryngology at Universiti Kebangsaan Malaysia. With comprehensive tertiary training from Hospital Kuala Lumpur and Hospital Tunku Azizah, he expertly manages complex adult and pediatric ENT conditions, including sinus, ear, throat, and vertigo disorders. Dr. Ameen currently serves as a sessional consultant at Sunway Medical Centre Velocity and Columbia Asia Hospital Setapak, and will join KPJ Ampang Puteri Specialist Hospital as a full-time resident specialist in August 2026.