Hi,

Thank you for your query.

1. Parosmia / Cacosmia or an altered smell like smoke may be experienced due to an number of reasons such as:
a. Nasal infections and chronic sinusitis.
b. Damage to the olfactory system due to any severe infection, head injury, exposure to solvents and volatile chemicals. What is your occupation?
c. Metabolic diseases such as hypothyroidism, liver dysfunction. Do you smoke or have alcohol? Have you undergone blood tests?
d. Rarely, degenerative brain disorders such as Parkinson's and Alzheimer's. Have you ever suffered from Epilepsy?
e. CT / MRI of the Brain and Para Nasal Sinuses may be required.

2. The bad smell that you get through your nose when you inhale is most likely due to a mild sinus infection or stagnant mucus including drying up of normal nasal secretions. Have you had a recent cold, cough or fever? The inflammation may be fungal. Foreign bodies are rare in adults but must be ruled out if it is one sided. A rotten smell usually means a sulphur containing compound usually produced by a bacterial infection. You may discuss the possibility of Biofilm formation in your sinuses with your physicians. Sometimes there are fungal infections and build up of waste products of inflammation, infection, immune system by-products and gases like nitric oxide and ammonia. This would explain the burnt smoke like smell which you experience. Due to their unique design, airflow through our sinuses and their ventilation occurs gently and passively during expiration. This may explain why you get the smell irregularly.

3. Hence the first step will be to rule out the above by a visit to an ENT Specialist.

4. Oral infections, inflammation including gum and dental (any recent root canal or dental extraction?), acid reflux and Tonsilloliths are leading causes for a bad smell in the nose.

5. Get a general check-up done as many diseases such as diabetes, liver diseases, nasal polyps, tumors and so on should be ruled out.

6. The sinuses may harbor silent infection. Fungal infections may exist only within the sinuses (as against invasive fungal infections) and yet cause allergic reactions. This constitutes Allergic Fungal Rhino Sinusitis (AFRS). Such fungal infections may be missed out on CT Scans and requires MRI Scans to detect. If there is nasal and sinus inflammation you may take a trial of treatment including antibiotics, anti-allergic decongestants, saline nasal washes, mouthwashes, tongue cleaning, anti-reflux medication and probiotics.

7. If no cause is found, it may be a an olfactory hallucination. This a commonly seen with damage to the olfactory mucosa or olfactory bulb and tract, esp. some years after a head injury. This will show up on imaging such as CT/MRI. Do you have any occupational exposure to extreme cold, constant air conditioning or chemicals? Conditions like atrophic rhinitis, post nasal drip and acid reflux may also co-exist.

8. You may follow up with the answers to the above questions, results of the above investigations and treatment for further recommendations.

I hope that I have answered your queries. If you have any further questions, I will be available to answer them.

Regards.

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