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Phantosmia: When Your Loved One Smells Things That Aren't There

Phantosmia, or olfactory hallucination, is when a person smells something that has no physical source. For someone with dementia, this can be a very real and distressing experience, often involving foul odors like smoke, burning rubber, or rotting food. While it can be unsettling, understanding why it happens and having a calm, practical response can make a world of difference. You are not alone in navigating this, and there are concrete steps you can take to help your loved one feel safe and supported.

Key points

  • Phantosmia is a real sensory experience for the person, not a lie or a sign of stubbornness. Always validate their feeling first.
  • Never argue or try to prove the smell isn't there. This will only increase their distress and damage trust.
  • Always rule out a real source (smoke, gas, spoiled food) before treating it as a hallucination.
  • Use redirection to a different sense (a pleasant smell, a familiar activity) to help their brain 'reset.'
  • Keep a log of episodes to share with the doctor, especially noting timing, triggers, and the person's level of distress.
  • A sudden onset of hallucinations can be a medical emergency (like a UTI). Always consult a doctor for a new or worsening symptom.

What Is Phantosmia and Why Does It Happen?

Phantosmia is a type of hallucination that affects the sense of smell. The person's brain is creating a smell that isn't actually present in the room. As one expert explains, a hallucination is when the brain tricks itself into thinking something is there when it is not, and it can impact any of the five senses. For phantosmia, the perceived odors can be foul or pleasant, and they may be constant or come and go. The person may notice the smell in one or both nostrils. This is not the person being difficult or confused about a real odor; it is a genuine sensory experience generated by changes in the brain.

Why Does This Happen in Dementia?

The underlying cause is damage to the brain regions that process smell. In Lewy body dementia, this is especially common and can be one of the earliest signs. One source notes that people with Lewy body dementia can have 'really nasty hallucinations like they smell feces in their food' or 'dead animals in the house,' and these can be very distressing. In Alzheimer's disease, hallucinations are less common overall—affecting only about 13% of people—and typically appear in the middle or later stages. However, any type of dementia can potentially cause phantosmia. It is also important to remember that a sudden onset of hallucinations can be a sign of a medical issue like a urinary tract infection, a medication side effect, or even a problem with the person's teeth or gums, so a medical check-up is always a good first step.

How Phantosmia Differs From a Real Smell or a Delusion

It is crucial to distinguish phantosmia from a real environmental smell or from a delusion. A delusion is a fixed, false belief, like thinking someone is poisoning their food. Phantosmia is a sensory experience—the person actually smells something. They are not making it up or being paranoid. As one source explains, a hallucination is 'a physical experience' for the person. If your loved one says they smell smoke, they are truly smelling it. Your job is not to convince them they are wrong, but to address the distress the smell is causing. If the smell is always the same and seems to come from nowhere, it is more likely phantosmia than a real odor.

General caregiving information, not medical advice. Check medications and major care changes with your clinician.

Step-by-step

  1. Stay calm and do not argue. Your first reaction might be to say, 'I don't smell anything.' Instead, take a breath and acknowledge their experience. Say something like, 'That must be really unsettling. I'm here with you.' This validates their reality without agreeing that the smell is real.

  2. Assess for immediate danger. If the smell is of smoke or gas, quickly and discreetly check the environment. Look for actual smoke, a gas leak, or a burning appliance. If you find a real source, address it immediately. If not, you can confidently move on to managing the hallucination.

  3. Use a simple, reassuring phrase. After you have checked, say, 'I just checked the whole house, and I don't see any smoke or fire. We are safe.' This provides a concrete, factual statement of safety without directly contradicting their experience. Avoid saying, 'You're imagining it.'

  4. Try to redirect their attention to a different sense. Offer them a strong, pleasant smell to focus on. For example, say, 'Let's go into the kitchen. I just made some coffee, and it smells wonderful. Would you like a cup?' Or, 'Here, smell this fresh lemon—it's so bright.' This can help 'reset' their olfactory focus.

  5. Change the environment. Open a window for fresh air, turn on a fan, or move to a different room. A change of scenery can sometimes break the cycle of the hallucination. If the smell is associated with a particular room (like the bathroom), avoid that room for a while.

  6. Engage them in a simple, hands-on activity. Offer a task that uses other senses, like folding towels, sorting socks, or looking at a familiar photo album. This can shift their brain's focus away from the phantom smell. The goal is to gently distract, not to force them to stop smelling it.

  7. Monitor the frequency and triggers. Keep a simple log: What time of day does it happen? What is your loved one doing? Is it after a meal or when they are tired? This information is very helpful for the doctor. Lewy body hallucinations often worsen in the evening or at night.

  8. If the smell is of something foul (like feces or rotting food), do not immediately assume it is a hallucination. Check their clothing and the immediate area for any real source of odor. If you find nothing, then proceed with the steps above. This prevents you from missing a real care need.

What not to do

  • Do NOT argue or try to prove them wrong. Saying 'There is no smell, you're hallucinating' will only make them feel confused, frightened, and defensive. It damages trust. Instead, validate their feeling: 'I know that smell is very real to you.'

  • Do NOT laugh or make jokes about the smell. Even if the smell seems absurd (like 'burning popcorn'), the experience is real and distressing for them. Treat it with the same seriousness you would if they smelled a real fire.

  • Do NOT immediately assume it is a sign of a worsening disease. While it can be, a sudden change in hallucinations can also be caused by a treatable medical issue like a urinary tract infection, constipation, or a medication side effect. Always rule out physical causes first by consulting a doctor.

  • Do NOT use strong air fresheners or scented candles to 'cover up' the phantom smell. This can confuse the person further and may even trigger a different hallucination. Stick to neutral, familiar scents like fresh air, coffee, or a plain lemon.

  • Do NOT leave them alone if they are very distressed by the smell. Your presence is the most powerful tool. Sit with them, hold their hand, and speak in a calm, soothing voice. Your reassurance that they are safe is more important than the smell itself.

Practical tools

  • The 'Safety Check' Script

    A simple, two-part phrase to use every time. Part 1: 'I hear you. That smell must be really bothersome.' Part 2: 'Let me just do a quick check around the house to make sure everything is okay.' Then, after a brief, visible check (even if you know it's a hallucination), return and say, 'I checked everywhere. We are safe. There is no smoke or gas. Let's sit down together.' This script validates, reassures, and provides a sense of control.

  • The 'Scent Switch' Kit

    Prepare a small basket with a few items that have strong, pleasant, and familiar scents. Examples: a fresh lemon or orange, a small container of ground coffee, a sprig of mint or lavender, a bar of their favorite soap. When a phantom smell occurs, offer one of these items and say, 'Here, smell this. It's so nice and fresh.' This can help 'override' the hallucination with a real, positive sensory input.

  • The 'Distraction Menu'

    Create a short, written list of 3-5 simple, calming activities that you can offer immediately after a phantosmia episode. Examples: 'Let's go look at the birds at the window,' 'Can you help me fold these napkins?' or 'Let's listen to that song you love.' Having a menu ready prevents you from having to think on your feet when you are stressed.

  • The 'Phantom Smell Log'

    A simple notebook or a note on your phone. Track: Date, time, what the person said they smelled, their level of distress (mild/moderate/severe), what you did, and if it helped. Also note any other symptoms (like confusion, fever, or a change in appetite). This log is invaluable for the doctor to see patterns and rule out other causes.

  • Environmental Check: Ventilation and Odor Sources

    Before assuming a smell is a hallucination, do a quick, systematic check: Look under the bed, in the trash can, near the pet's area, and in the kitchen. Check for any spoiled food, a dirty diaper, or a musty towel. If you find a real source, remove it. If not, you can confidently proceed with the hallucination protocol.

Discuss with your clinician

If the phantosmia is new, sudden, or accompanied by other symptoms like fever, confusion, or a change in behavior, discuss with a doctor immediately to rule out a urinary tract infection or other medical cause.

If the hallucinations are very frequent, distressing, or causing the person to become agitated or aggressive, ask the doctor if a medication review or a referral to a neurologist or geriatric psychiatrist is appropriate.

If the person is on any medications (including over-the-counter), ask the pharmacist or doctor if phantosmia could be a side effect. Do not stop or change any medication without professional guidance.

If the person has Lewy body dementia and the phantosmia is severe, discuss the risks and benefits of any antipsychotic medication with a specialist, as these drugs can have serious side effects in LBD.

If the person also has a dental issue or complains of a bad taste in their mouth, ask the doctor about a dental check-up, as oral infections can sometimes cause phantom smells or tastes.

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