What to explain
Explain the nasal symptoms, how long they have lasted, and what happens to your thinking and sleep.
I'd like to discuss whether allergies, chronic sinusitis, nasal polyps, a blocked nasal passage, a medicine, migraine, poor sleep, or another health problem could be contributing to my brain fog. Could we review my nasal symptoms, how long they have lasted, and decide what examination or tests may help?
Questions to take in
Ask what is inflamed or blocked, what needs proof, and what can be treated safely.
- Do my symptoms meet the 12-week definition of chronic rhinosinusitis, and is there objective inflammation on examination, nasal endoscopy, or CT?
- Does this look more like allergic rhinitis, non-allergic rhinitis, polyps, septal or turbinate blockage, migraine, dental disease, or medicine-related rebound congestion?
- Could an older antihistamine, sleep aid, decongestant, combination cold product, or another medicine be worsening my thinking or nasal blockage?
- Do my snoring, dry mouth, morning headaches, breathing pauses, or daytime sleepiness justify a sleep study?
- Would allergy testing change treatment, and which allergens match my symptoms and exposures?
- If I have polyps, asthma, or reactions to aspirin or anti-inflammatory pain medicines, should an allergist and ENT assess me together?
- If we're considering surgery, what finding will it treat, what benefit is realistic, what complications matter, and how likely are ongoing medicines or repeat surgery?
- When should we repeat the examination, SNOT-22, endoscopy, or another assessment, and what improvement or worsening should change the plan?
Examinations and tests that may help
What each nasal, allergy, medicine, blood, or sleep assessment can show.
There is no single sinus blood test. A clinician starts with the symptoms, duration, nasal examination, medicine use, sneezing or itchy eyes, sleep symptoms, and signs that need faster care.
ENT Examination and Nasal Endoscopy
An ENT clinician can look for polyps, swelling, pus, a deviated septum, enlarged turbinates, or a one-sided mass. Nasal endoscopy can provide the objective evidence needed to confirm chronic rhinosinusitis.
Ask your doctorSNOT-22 Symptom Questionnaire
SNOT-22 records nasal, sleep, ear, facial, and daily-life symptoms. It can measure change during treatment, but the score does not identify the cause by itself.
Ask your doctorCT Sinuses
A sinus CT can confirm inflammation and show anatomy when symptoms persist, complications are suspected, or surgery is being planned. It is not a routine test for every blocked nose.
Ask your doctorAllergy Testing
Skin-prick testing or specific IgE blood testing may help when sneezing, itching, watery eyes, seasons, animals, dust mites, or pollen suggest allergy. Food IgG panels do not diagnose nasal allergy.
Ask your doctorMedication Review
A medication review checks antihistamines, decongestants, nasal sprays, sleep aids, blood-pressure medicines, and supplements. It can find sedation, rebound congestion, duplicate ingredients, poor timing, or unsafe combinations.
Read the test guideAnticholinergic Burden Review
An anticholinergic review can identify older allergy and sleep medicines that cause dry mouth, drowsiness, blurred vision, memory trouble, or confusion, especially when several are used together.
Read the test guideSleep Study (PSG)
A sleep study can assess sleep apnea when snoring, gasping, witnessed breathing pauses, morning headaches, dry mouth, or severe daytime sleepiness occurs. Nasal blockage alone doesn't prove sleep apnea.
Read the test guideCBC with Differential
A CBC with differential may help check for suspected recurrent infection, anemia, immune problems, or eosinophilic inflammation. It cannot confirm chronic sinusitis or decide biologic treatment by itself.
Read the test guideBefore the appointment
Bring dates, medicine labels, earlier results, and examples of what the problem stops you doing.
The date symptoms began and whether blockage, discharge, facial pressure, reduced smell, sneezing, itching, watery eyes, headache, or dental pain occurs.
Whether symptoms affect the left side, right side, or both sides. Include nosebleeds, bloody discharge, crusting, bad smell, facial numbness, eye swelling, or vision change.
A list of seasons, rooms, buildings, jobs, pets, smoke, perfumes, cleaning products, foods, exercise, cold air, or medicines that clearly change symptoms.
Every nasal spray, rinse, antihistamine, decongestant, sleep aid, pain medicine, supplement, and recently stopped product. Bring labels or photographs.
Earlier nasal examinations, endoscopy reports, sinus CT images or reports, allergy tests, CBC results, sleep studies, dental records, and surgery notes.
A seven-day note of nasal blockage, smell, facial pressure, headache, sleep, snoring, medicine timing, brain fog, and one daily task that became harder.
Two examples of reading, driving, work, school, cooking, medicine use, or conversations becoming slower, less accurate, or unsafe.
A partner or family observation of snoring, gasping, breathing pauses, mouth breathing, restless sleep, or daytime sleepiness, if available.
For example: My nose has been blocked most days for four months, I wake with a dry mouth, and I now lose my place while reading at work.
How the doctor assesses this
Details that help a clinician tell chronic sinusitis, allergy, polyps, and structural blockage apart
- Nasal blockage or discharge has lasted at least 12 weeks, with facial pressure, reduced smell, or both.
- Sneezing, an itchy nose, watery eyes, or a clear pollen, dust, pet, smoke, or workplace trigger occurs with the congestion.
- Reduced smell, visible polyps, asthma, or breathing trouble after aspirin or an anti-inflammatory pain medicine occurs with the nasal symptoms.
Reasons to check migraine, sleep apnea, medicine effects, dental disease, and neurological causes too
- Chronic rhinosinusitis becomes less likely when symptoms have lasted under 12 weeks and examination, endoscopy, or CT does not show nasal or sinus inflammation.
- Allergic rhinitis becomes less likely when there is no sneezing, itching, watery eyes, clear discharge, seasonal change, or repeatable exposure trigger.
- A migraine becomes more likely when you have face pressure with nausea, light or sound sensitivity, throbbing pain, or attacks without ongoing nasal blockage or discharge.
- Sleep apnea may explain more when loud snoring, gasping, witnessed breathing pauses, morning headache, dry mouth, or severe daytime sleepiness continues after nasal symptoms improve.
- A medicine may explain more when thinking problems start after diphenhydramine, doxylamine, a decongestant, a sleep medicine, or another sedating drug and change with its timing.
What to understand before choosing care
Decisions to make about diagnosis, medicines, sleep testing, specialist care, and follow-up.
- Confirm whether the problem is chronic rhinosinusitis, allergic rhinitis, non-allergic rhinitis, nasal polyps, or a structural blockage before choosing advanced treatment.
- Ask a clinician or pharmacist to check spray technique, medicine ingredients, sedation, rebound congestion, blood pressure risks, pregnancy, and possible interactions.
- Use only distilled, sterile, or boiled and cooled water for nasal rinsing. Clean the device after use and follow its instructions.
- Discuss sleep testing when snoring, gasping, breathing pauses, morning headache, dry mouth, or marked daytime sleepiness occurs.
- Before surgery, ask what finding the operation will treat, what improvement is realistic, what follow-up you'll need, and whether inflammation or polyps may return.
What the research found
What 2024 to 2026 evidence says about chronic sinusitis, thinking, diagnosis, surgery, and nasal polyps.
A 2025 meta-analysis included 10 studies and 107,610 patients. It linked chronic rhinosinusitis to 9% poorer overall thinking ability, and treatment to 8% to 9% gains in processing speed and working memory.
The 2025 meta-analysis found no significant link with dementia in studies that checked people once. Its authors said larger long-term studies are still needed.
A 2024 clinic study compared 24 people with chronic rhinosinusitis and 23 controls. Mild or greater cognitive impairment occurred in 41.7% and 8.7%, respectively.
The 2024 study used objective cognitive and eye-movement tests, but its small specialist-clinic sample cannot provide a population rate or predict one person's recovery.
The 2025 surgical guideline says to confirm the diagnosis before surgery and to expect possible relapse, long-term medical care, and follow-up between 3 and 12 months.
How childhood, older age, sex, pregnancy, asthma, and nasal polyps can change the assessment.
Children need pediatric assessment. Enlarged adenoids, an object in the nose, allergy, asthma, cystic fibrosis, immune problems, and sleep-disordered breathing can require different examinations or referrals from those used for adults.
In teenagers and adults, repeated sinus disease with asthma, polyps, or breathing trouble after aspirin or anti-inflammatory pain medicines can require ENT and allergy care.
ASCIA states that pregnancy rhinitis affects up to 20% of pregnant women, often begins in the second trimester, and usually improves within two weeks after birth.
Older adults may have non-allergic rhinitis, nasal dryness, thyroid disease, previous radiation, several medicines, or greater harm from sedating and anticholinergic products.
Females reported sinusitis more often, while males more often had nasal polyps and higher scan scores, a 2025 review found. These averages can't diagnose one person.
If the answer is no
If your doctor will not order sinus imaging
A scan is not the usual first step for a simple, short-term sinus illness. The American Academy of Otolaryngology says not to order a scan for acute sinusitis unless a complication or another illness is suspected. Your history and exam decide whether a scan, a camera exam inside the nose, or another check would help.
What changes the answer
- Show how long the problem has lasted. Bring the start date, times it improved, nasal blockage, drainage, face pressure, loss of smell, and treatments you tried.
- Ask which illness matches your symptoms. A virus, bacterial sinus infection, allergy, migraine, and long-term sinus swelling need different tests and treatment.
- Name signs that may need imaging. Eye swelling, vision changes, severe symptoms on one side, or a new nerve problem can change the decision.
- Ask about another way to check. An exam, allergy testing, a camera exam inside the nose, a treatment trial, or an ear, nose, and throat referral may answer the question without a scan.
United States, United Kingdom, and Australia
Who to contact about Chronic Sinusitis and Brain Fog.
US United States
Book primary care, allergy, or ENT care. Bring symptom dates, medicine labels, earlier scans, allergy and sleep results, and examples of daily difficulty. Ask what evidence it takes to change treatment.
- Start with primary care, an allergist, or an ENT clinician. Chronic rhinosinusitis should be confirmed with symptoms plus objective inflammation before advanced treatment.
- The guideline covers nasal examination, endoscopy, CT, allergy and immune testing, saline, intranasal steroids, antibiotics, and biologics according to the diagnosis.
- The ACAAI patient guide updated in January 2026 explains that antibiotics treat a bacterial infection, not the inflammation that causes nasal polyps.
UK United Kingdom
See a pharmacist or GP. Take the symptom duration, medicine list, one-sided symptoms, sleep concerns, and earlier results. Ask when ENT, allergy, sleep, dental, or migraine assessment is appropriate.
- A pharmacist or GP can review persistent symptoms and medicines. ENT referral may follow three months of symptoms or treatment, repeat episodes, or one-sided symptoms.
- NHS guidance includes steroid nasal sprays or drops, antihistamines when allergy is responsible, and surgery for selected chronic cases.
- NICE 2026 guidance makes dupilumab available for selected adults with severe nasal polyps after previous treatment and sinus surgery under stated NHS criteria.
AU Australia
See a GP. Bring symptom dates, medicine labels, sneezing or itchy-eye symptoms, sleep concerns, earlier tests, and daily examples. Ask whether you need ENT, allergy, sleep, dental, or migraine assessment.
- Start with a GP for symptoms, medicines, asthma, sleep, and urgent signs. You may need an ENT surgeon or clinical immunology and allergy specialist.
- ASCIA distinguishes non-allergic rhinitis, allergic rhinitis, and chronic rhinosinusitis with nasal polyps because symptoms and treatment can differ.
- Healthdirect advises medical review for severe, worsening, or persistent sinusitis and explains that chronic disease may follow allergy or a structural nasal problem.
Safety
Show how it affects daily life
- For seven days, rate nasal blockage, smell, facial pressure, headache, sleep, and brain fog from 0 to 10 at the same times each day.
- Record one difficult task each day, what went wrong, and whether nasal symptoms, poor sleep, a medicine dose, pollen, smoke, or a building exposure occurred first.
- Use prescribed nasal sprays exactly as shown. Record missed doses and technique problems instead of assuming the medicine failed.
- If using a nasal rinse, use distilled, sterile, or boiled and cooled water. Stop and seek advice for severe pain, bleeding, fever, confusion, or vomiting.
- Do not test the cause by overusing a decongestant, stopping prescribed medicine, exposing yourself to an allergen, driving while sleepy, or delaying urgent care.
- At follow-up, compare symptoms and daily tasks with examination findings, medicine use, allergy exposure, sleep results, and any treatment change.
Source checked
Sources behind this handout.
- 01
Gao EY et al. Chronic rhinosinusitis and cognition: a systematic review and meta-analysis. Rhinology. 2025. Ten studies, 107,610 patients. PMID: 40619980.
Source - 02
Cvancara DJ et al. Cognition and saccadic eye movement performance are impaired in chronic rhinosinusitis. International Forum of Allergy and Rhinology. 2024. PMID: 38268115.
Source - 03
Payne SC et al. Clinical Practice Guideline: Adult Sinusitis Update. Otolaryngology-Head and Neck Surgery. 2025. PMID: 40742114.
Source - 04
Shin JJ et al. Clinical Practice Guideline: Surgical Management of Chronic Rhinosinusitis. Otolaryngology-Head and Neck Surgery. 2025. PMID: 40424072.
Source - 05
Thornton CS et al. Sex and gender in rhinosinusitis: a review. Future Microbiology. 2025. PMID: 39673394.
Source - 06
Centers for Disease Control and Prevention. How to safely rinse sinuses. Updated July 16, 2025.
Source