Rhinology: Nose Anatomy, Smell, Taste and Common Conditions

DCM 2203 · Ear, Nose and Throat Care · LWA 3: Rhinology

Nose anatomy and physiology provide the basis for understanding airflow, smell, taste and common nasal disease. These notes follow the DCM 2203 Rhinology outline: the external nose and nasal cavity, paranasal sinuses, physiology of smell and taste, allergic rhinitis, rhinosinusitis, nasal foreign bodies, epistaxis and nasal polyps.

Core principle: Nasal obstruction, discharge, smell loss and bleeding are symptoms, not diagnoses. Use the pattern, duration, laterality, examination and associated features to identify the likely cause and decide when referral is needed.

1. Rhinology: scope and clinical approach

Rhinology is the study of the nose, nasal cavity, paranasal sinuses and related disorders. Common presentations include obstruction, sneezing, nasal discharge, facial pressure, smell change and epistaxis. A focused history should establish whether symptoms are acute or chronic, bilateral or unilateral, intermittent or persistent, and whether they follow infection, allergen exposure, trauma, medication use or foreign-body insertion.

Common symptom terms

• Rhinorrhoea: nasal discharge, which may be watery, mucoid, purulent or blood-stained.
• Nasal obstruction/congestion: reduced airflow through one or both nostrils.
• Hyposmia/anosmia: reduced or absent smell.
• Parosmia: familiar smells are perceived as distorted; phantosmia is perception of a smell without an external odour source.
• Epistaxis: bleeding from the nasal cavity.
• Facial pressure or pain: may occur with sinus inflammation but can also arise from dental, migraine, neuralgic or other causes.

2. Anatomy of the nose

Septum, conchae and drainage

The nasal septum divides the cavity into right and left sides. It is formed mainly by the septal cartilage anteriorly and the perpendicular plate of the ethmoid and vomer posteriorly. A deviation may be asymptomatic or contribute to obstruction. The nasal conchae (turbinates) project from the lateral wall; they increase surface area and create airflow turbulence so air contacts the vascular mucosa.

The meatuses are spaces beneath the conchae. Several sinuses and the nasolacrimal duct drain into the lateral nasal wall. The maxillary, frontal and anterior ethmoid sinuses drain through the middle meatus region; posterior ethmoid cells drain higher, and the sphenoid sinus opens into the sphenoethmoidal recess. Obstruction of drainage pathways can contribute to sinus symptoms.

Blood supply and innervation

The anterior nasal septum contains an anastomotic vascular area (Kiesselbach/Little’s area) and is a common site of anterior epistaxis. Posterior bleeding can arise from deeper arterial branches and may be more difficult to control. General sensation is carried mainly by branches of the trigeminal nerve; olfactory sensation is carried by cranial nerve I. Autonomic pathways regulate nasal gland secretion and vascular tone.

3. Nasal functions and smell/taste physiology

Functions of the nose

• Air conditioning: the mucosa warms and humidifies inspired air.
• Filtration and defence: hairs, mucus and ciliary movement trap and clear particles and microbes toward the pharynx.
• Olfaction: the upper nasal cavity detects odour molecules.
• Resonance: the nasal cavities and sinuses contribute to voice quality.
• Drainage: mucus from the sinuses and tears from the nasolacrimal duct pass into the nasal cavity.

How smell works

Odour molecules dissolve in mucus and stimulate receptor proteins on olfactory sensory neurons in the specialised epithelium high in the nose. Signals pass through the cribriform plate to the olfactory bulbs and then along central pathways for perception and identification. Airborne odours enter through the nostrils. During eating, volatile molecules can also move from the back of the mouth into the nose (retronasal olfaction), contributing strongly to flavour.

How taste relates to smell

Taste receptors in the mouth and throat detect basic taste qualities such as sweet, sour, salty, bitter and umami. Flavour also depends on smell, temperature, texture and the common chemical sense, such as the cooling sensation of menthol or the irritation of chilli. A patient who says food has “no taste” may have reduced smell from congestion, infection or nasal obstruction rather than a primary taste disorder. Persistent smell or taste change deserves assessment, particularly after head trauma or when associated with obstruction, bleeding or neurologic symptoms.

4. Clinical assessment of nasal symptoms

Focused history

• Onset, duration, pattern, laterality, triggers and progression; recent cold or other respiratory infection; seasonal or household/work exposures.
• Character and amount of discharge, sneezing, itching, facial pain/pressure, fever, cough, smell change, bleeding, eye symptoms and sleep disturbance.
• Trauma, nose picking, forceful nose blowing, foreign-body insertion, previous nasal surgery, dental infection or known septal deviation.
• Atopy, asthma, eczema, medication use (including topical decongestants), anticoagulants, bleeding history, immunosuppression and relevant family history.
• In a child, ask about unilateral foul-smelling or blood-stained discharge, choking/coughing, possible insertion of an object and any caregiver observation.

Examination

1. Assess general condition and airway. Record vital signs when the patient is systemically unwell or actively bleeding.
2. Inspect the face, external nose and nostrils for swelling, asymmetry, trauma, deformity, skin changes and discharge.
3. Perform gentle anterior rhinoscopy with good light and an appropriate speculum. Look for mucosal colour and swelling, septal deviation or perforation, crusts, active bleeding, a foreign body, discharge, polyps or a mass. Do not probe blindly.
4. Examine the mouth, teeth, oropharynx and eyes as indicated. Check for facial tenderness and orbital signs when sinusitis complications are possible.
5. Document whether disease is unilateral or bilateral and whether a complete view was possible. Refer for nasal endoscopy or imaging when the clinical question warrants it.

Many cases of uncomplicated allergic rhinitis or acute rhinosinusitis are assessed clinically. Allergy testing can help when the diagnosis is uncertain or when results will change management. Nasal endoscopy and CT are generally reserved for persistent, recurrent, complicated or otherwise concerning disease rather than routine uncomplicated acute symptoms. Investigations should answer a specific clinical question.

5. Allergic rhinitis

Allergic rhinitis is an inflammatory nasal response triggered by exposure to an allergen in a sensitised person. It may be intermittent or persistent and may occur alongside asthma, eczema or allergic conjunctivitis. Common triggers include house-dust mite, pollen, mould and animal dander; the relevant exposure varies between patients and settings.

Clinical features

• Repeated sneezing, nasal itch, clear watery discharge and bilateral obstruction or congestion.
• Itchy, watery eyes and throat irritation may accompany nasal symptoms.
• Symptoms that recur with a particular season, place or exposure support an allergic cause.
• Examination may show pale or boggy swollen mucosa and watery secretions, although appearance alone does not confirm allergy.

Assessment and management principles

Ask about triggers, symptom burden, sleep, school/work and asthma control. Distinguish allergic rhinitis from acute viral infection, non-allergic rhinitis, medication-induced congestion, sinusitis, a foreign body and structural obstruction. Allergy testing is useful when the result will clarify the diagnosis or guide avoidance or specialist treatment.

Management is tailored to severity and local availability. Options include reducing relevant exposures where practical, saline nasal care, intranasal corticosteroids, intranasal antihistamines or suitable oral antihistamines. Correct spray technique improves delivery: direct the nozzle slightly outward away from the septum and sniff gently rather than forcefully. Long-term or frequent topical decongestant use can cause rebound congestion; avoid prolonged use and follow current local and national guidance. Persistent symptoms, poor asthma control, unilateral findings or uncertainty warrant clinical review. Immunotherapy is a specialist option for selected patients.

6. Rhinosinusitis

Rhinosinusitis is inflammation of the nasal cavity and paranasal sinuses. Acute symptoms commonly follow a viral upper-respiratory infection; chronic rhinosinusitis persists over a longer period and may be associated with mucosal disease, polyps or structural obstruction.

Acute rhinosinusitis

Symptoms can include nasal obstruction, nasal discharge, facial pressure or pain, reduced smell and cough. Many acute episodes improve without antibiotics. A bacterial cause becomes more likely when symptoms persist without improvement, are unusually severe from the beginning, or worsen again after initial improvement, but no single symptom proves bacterial disease. Consider dental disease, migraine, allergic rhinitis and other causes of facial pain or discharge.

For uncomplicated illness, care is usually supportive and aims to relieve symptoms; antibiotic decisions should follow the current Uganda Clinical Guidelines and facility policy. NICE NG79 and the AAO-HNS adult guideline provide additional stewardship guidance, but they are not substitutes for Uganda’s local recommendations. Avoid routine imaging for an uncomplicated acute presentation. Consider specialist assessment or imaging when symptoms are recurrent, persistent, atypical, severe or suggest complications.

Chronic rhinosinusitis

Chronic symptoms usually include nasal obstruction or discharge, often with facial pressure and reduced smell, persisting for weeks to months. Examination or endoscopy may show mucosal inflammation, discharge or polyps. Persistent symptoms can affect sleep, concentration, school/work and quality of life. Evaluate for allergic disease, asthma, medication effects, dental sources, immune problems or structural obstruction where relevant. Long-term treatment and the need for endoscopy, CT or surgery depend on the individual findings and specialist pathway.

Complications

Sinus infection can rarely spread to the orbit, bones or intracranial spaces. Periorbital swelling, painful or restricted eye movement, double vision, reduced vision, proptosis, severe frontal headache, neck stiffness, confusion, focal neurologic signs or systemic toxicity requires urgent hospital assessment.

7. Nasal polyps

Nasal polyps are soft, usually pale or translucent, oedematous growths arising from inflamed mucosa, commonly in association with chronic rhinosinusitis. Bilateral polyps may cause progressive obstruction, reduced smell, mouth breathing, discharge and a hyponasal voice. They are usually not tender when gently observed with appropriate examination.

Do not assume that every nasal mass is a polyp. A unilateral mass, recurrent one-sided bleeding, facial numbness, severe pain, rapid growth, visual symptoms or a mass in a child requires prompt ENT assessment to exclude other pathology. Avoid biopsy or forceful manipulation outside an appropriate specialist setting. Management may include topical anti-inflammatory treatment and specialist review; persistent obstruction, recurrent disease or poor response needs referral.

8. Epistaxis (nosebleed)

Epistaxis is bleeding from the nasal cavity. Anterior bleeding, often from the vascular anterior septum, is common. Posterior bleeding may be heavier, less visible and more difficult to control. Causes and contributing factors include local dryness or inflammation, nose picking or instrumentation, trauma, a foreign body, medicines affecting clotting and less commonly a tumour or systemic bleeding disorder.

First aid for an active nosebleed

1. Sit the person upright and lean them forward so blood does not run into the throat. Encourage breathing through the mouth and spitting out blood rather than swallowing it.
2. Apply firm, continuous pressure to the soft lower part of both sides of the nose for at least five minutes. Do not keep releasing pressure to check.
3. If bleeding continues, the person becomes faint or breathless, blood is heavy, there is significant trauma, or the patient has a bleeding disorder or is taking anticoagulants, seek urgent medical care.
4. After bleeding stops, avoid picking, vigorous nose blowing and strenuous activity for a short period; follow local advice and investigate recurrent episodes.

Clinical assessment and escalation

Assess airway, breathing and circulation when bleeding is severe. Ask about duration, recurrence, trauma, medicines, easy bruising, bleeding elsewhere and family history. Examine the nose when bleeding is controlled and the patient is stable. A visible anterior source may be treated by a trained clinician using appropriate local measures; cautery, nasal packing and other interventions require competence, equipment and follow-up. Recurrent unilateral bleeding, persistent obstruction, suspected tumour, posterior bleeding or failure of initial measures warrants ENT assessment.

9. Nasal foreign bodies

Nasal foreign bodies occur most often in young children and may be unwitnessed. Symptoms include unilateral obstruction, discharge that becomes foul-smelling, blood-stained secretions, pain or intermittent nosebleeds. Consider an object when a child has persistent one-sided symptoms that do not fit a simple cold.

Do not probe blindly, repeatedly attempt removal or flush an unknown object. A button battery or paired magnets can rapidly damage tissue and needs urgent skilled removal; delay increases injury. Posterior objects may move toward the airway. Arrange urgent assessment when the object is deep, poorly seen, embedded, associated with bleeding or distress, or when the child cannot cooperate. A trained clinician should choose a removal method appropriate to the object and setting, then check the mucosa and ensure no fragment remains.

10. Red flags and referral

• Airway compromise, choking, suspected aspiration, severe facial trauma or rapidly worsening obstruction.
• Button battery or paired magnets in the nose; a deeply lodged or uncooperative-child foreign body.
• Severe or persistent epistaxis, haemodynamic symptoms, recurrent unilateral bleeding or bleeding with a clotting disorder/anticoagulant use.
• Eye swelling, visual loss, diplopia, proptosis, painful/restricted eye movements or severe frontal headache with suspected sinusitis.
• Neck stiffness, altered consciousness, focal neurologic deficit, severe systemic illness or suspected intracranial spread.
• Clear watery discharge after head injury, especially with headache or neurologic symptoms; possible CSF leak needs urgent evaluation.
• Unilateral nasal obstruction or mass, recurrent blood-stained discharge, facial numbness, rapidly progressive symptoms or a suspected tumour.
• Persistent smell loss after trauma, prolonged symptoms despite appropriate care, recurrent sinusitis, severe asthma/allergic disease or major effect on daily function.

11. Worked examples and self-check

Self-check questions

1. Name the four paranasal sinuses.
2. What do nasal conchae contribute to inspired-air conditioning?
3. Why can a person with a blocked nose report that food has lost its flavour?
4. Give three features that make allergic rhinitis likely.
5. Why are antibiotics not needed for every acute rhinosinusitis episode?
6. What is the correct direction for leaning during first aid for epistaxis?
7. Which nasal foreign bodies require urgent skilled removal?
8. Name three urgent sinusitis complication signs.

Answers: 1. Maxillary, frontal, ethmoid and sphenoid. 2. They increase mucosal surface area and create turbulence so air is warmed, humidified and filtered. 3. Retronasal smell is a major part of flavour; obstruction stops odours reaching olfactory receptors. 4. Sneezing, itching, clear watery discharge, bilateral congestion, eye itch/watering or a reproducible exposure pattern. 5. Many cases are viral and self-limiting; antibiotic decisions should reflect clinical course and local guideline. 6. Sit upright and lean forward. 7. Button batteries and paired magnets are emergencies; deeply lodged objects and cases with distress or poor visibility also need trained care. 8. Eye swelling or impaired movement/vision, severe frontal headache, meningism, confusion or focal neurologic signs.

12. Key points to remember

• The nose conditions inspired air, supports smell and contributes to flavour, voice resonance and drainage.
• Allergic rhinitis typically causes bilateral itch, sneezing and clear discharge; unilateral or bloody symptoms need another explanation.
• Most acute rhinosinusitis does not automatically need antibiotics or imaging; use the current Uganda guideline and reassess when symptoms worsen or persist.
• Persistent unilateral obstruction, recurrent bleeding, a nasal mass, orbital symptoms or neurologic signs needs prompt assessment.
• For epistaxis, sit forward and apply continuous pressure to the soft lower nose; seek urgent help for severe, ongoing or complicated bleeding.
• Never blindly probe or flush a nasal foreign body; a battery or magnets need urgent skilled removal.

References and further reading

1. Uganda Ministry of Health. Uganda Clinical Guidelines 2023. Use current national and facility protocols for diagnosis, medicines, referral and follow-up.
2. National Institute on Deafness and Other Communication Disorders (NIDCD). Smell Disorders.
3. NIDCD. Taste Disorders.
4. ARIA–EAACI. 2024–2025 Guidelines on the Treatment of Allergic Rhinitis.
5. American Academy of Otolaryngology–Head and Neck Surgery. Clinical Practice Guideline: Adult Sinusitis Update, 2025.
6. National Institute for Health and Care Excellence. Sinusitis (acute): antimicrobial prescribing, NG79. International reference; local Uganda guidance takes precedence.
7. European Rhinologic Society. European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS 2020).
8. American Academy of Otolaryngology–Head and Neck Surgery. Clinical Practice Guideline: Nosebleed (Epistaxis), 2020.

Class notes: Coming soon.