[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Head and neck](https://durgical.com/en/general-pathology/areas/head-neck/) › Rhinitis, sinusitis, pharyngitis and tonsillitis

# Rhinitis, sinusitis, pharyngitis and tonsillitis

- Lesion

Viruses and allergens inflame the nose and throat. Repeated attacks cause polyps, blocked sinuses and bacterial infection.

Updated Nov 12, 2026

## Key points

- Common cold: rhinoviruses, adenoviruses, coronaviruses; edematous red mucosa with profuse catarrhal discharge.
- Allergic rhinitis: IgE-mediated early and late phase; eosinophil-rich infiltrate; associated with asthma and eczema.
- Nasal polyps: edematous stroma with eosinophils, glands and plasma cells; with aspirin-exacerbated respiratory disease (asthma, polyps, NSAID sensitivity) and cystic fibrosis (polyps in a child suggest CF).
- Sinusitis: usually after rhinitis; maxillary sinusitis can come from a dental (periapical) infection; obstructed frontal sinus can form a mucocele.
- Mucormycosis of the sinuses in diabetic ketoacidosis or neutropenia: invasive, destructive, can reach the orbit and brain.
- Group A streptococcal pharyngitis can lead to rheumatic fever and post-streptococcal glomerulonephritis.

## What it is

The upper airway is the commonest site of infection and allergy. Infectious rhinitis (the common cold) is viral; allergic rhinitis is a type I hypersensitivity. Repeated inflammation produces nasal polyps and chronic rhinitis, and blocked drainage leads to sinusitis. Pharyngitis and tonsillitis are mostly viral, with group A Streptococcus the important bacterial cause.

## Structure

- Rhinitis: mucosal edema, vascular congestion, mononuclear or eosinophilic infiltrate; mucus overproduction.
- Nasal polyp: smooth, grey, gelatinous mass; loose edematous stroma, hyperplastic or cystic glands, eosinophils, neutrophils and plasma cells.
- Chronic sinusitis: thickened mucosa, chronic inflammation, sometimes squamous metaplasia and fibrosis.
- Tonsillitis: reactive follicular hyperplasia, crypt abscesses with neutrophils and exudate.

## Step by step

- Viruses or allergens trigger edema and mucus in the nasal mucosa.
- Swollen mucosa blocks the sinus ostia and Eustachian tubes.
- Trapped secretions are invaded by bacteria from the nasopharynx or mouth: acute sinusitis or otitis.
- Repeated inflammation makes the mucosa protrude into the cavity (polyps), further blocking drainage.
- Persistent obstruction leads to chronic sinusitis; in impaired hosts fungi invade.

## Upper airway inflammation

| Condition | Main cause | Key lesion |
| --- | --- | --- |
| [Allergic rhinitis](https://durgical.com/en/conditions/allergic-rhinitis/) | IgE to pollen, dust mites, dander | Edema with eosinophils |
| [Nasal polyps](https://durgical.com/en/conditions/chronic-rhinosinusitis-and-nasal-polyps/) | Recurrent rhinitis, AERD, cystic fibrosis | Edematous stroma, eosinophils |
| [Acute sinusitis](https://durgical.com/en/conditions/acute-rhinosinusitis/) | Viral then bacterial (oral and nasal flora) | Mucosal edema, pus in sinus |
| [Streptococcal pharyngitis](https://durgical.com/en/conditions/streptococcal-pharyngitis/) | Group A Streptococcus | Exudative tonsillitis, crypt abscesses |
| [Peritonsillar abscess](https://durgical.com/en/conditions/peritonsillar-abscess/) | Spread of tonsillitis | Pus between tonsil capsule and constrictor |

## Clinical notes

- Most upper respiratory infections are viral and resolve without antibiotics.
- Polyps cause nasal obstruction and loss of smell; recurrent polyps in a child prompt a sweat test for CF.
- Peritonsillar abscess is a complication of tonsillitis needing drainage.

## Memory aid

Asthma, aspirin and polyps travel together (Samter triad).

## Test yourself

Think of the answer, then tap the question to see it.

## What disease should nasal polyps in a child suggest?

Cystic fibrosis.

## What is aspirin-exacerbated respiratory disease?

The triad of asthma, nasal polyps and sensitivity to aspirin and other NSAIDs, driven by excess leukotrienes.

## Which fungal sinus infection is a threat in diabetic ketoacidosis?

Mucormycosis, which invades vessels and can spread from the sinuses to the orbit and brain.

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## Elsewhere in DurgiPedia

- [Type I hypersensitivity (immediate, IgE)](https://durgical.com/en/immunology/type-i-hypersensitivity/)
- [Mucosa-associated lymphoid tissue (tonsils, Peyer patches)](https://durgical.com/en/immunology/mucosa-associated-lymphoid-tissue/)
- [The airway: from nose to bronchioles](https://durgical.com/en/histology/the-airway-from-nose-to-bronchioles/)
- [Thymus and tonsils under the microscope](https://durgical.com/en/histology/thymus-and-tonsils-under-the-microscope/)

## Connections

## Related 4

- [Asthma: pathology](https://durgical.com/en/general-pathology/asthma-pathology/)
- [Necrotizing lesions of the nose and upper airway](https://durgical.com/en/general-pathology/necrotizing-lesions-of-the-nose-and-upper-airway/)
- [The ear: otitis media, cholesteatoma, otosclerosis and ear tumours](https://durgical.com/en/general-pathology/the-ear-otitis-media-cholesteatoma-otosclerosis-and-ear-tumours/)
- [Patterns of acute inflammation: serous, fibrinous, purulent, abscess, ulcer](https://durgical.com/en/general-pathology/patterns-of-acute-inflammation-serous-fibrinous-purulent-abscess-ulcer/)

## Related conditions 7

- [Allergic rhinitis](https://durgical.com/en/conditions/allergic-rhinitis/)
- [Acute rhinosinusitis](https://durgical.com/en/conditions/acute-rhinosinusitis/)
- [Chronic rhinosinusitis and nasal polyps](https://durgical.com/en/conditions/chronic-rhinosinusitis-and-nasal-polyps/)
- [Cystic fibrosis](https://durgical.com/en/conditions/cystic-fibrosis/)
- [Streptococcal pharyngitis](https://durgical.com/en/conditions/streptococcal-pharyngitis/)
- [Tonsillar hypertrophy and recurrent tonsillitis (post-tonsillectomy care)](https://durgical.com/en/conditions/tonsillar-hypertrophy-and-recurrent-tonsillitis/)
- [Peritonsillar abscess](https://durgical.com/en/conditions/peritonsillar-abscess/)

[← All of general pathology](https://durgical.com/en/general-pathology/)

Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Allergic Rhinitis](https://www.ncbi.nlm.nih.gov/books/NBK538186/) (StatPearls (NCBI Bookshelf), 2025); [Acute Sinusitis](https://www.ncbi.nlm.nih.gov/books/NBK547701/) (StatPearls (NCBI Bookshelf), 2025); [Streptococcal Pharyngitis](https://www.ncbi.nlm.nih.gov/books/NBK525997/) (StatPearls (NCBI Bookshelf), 2025).

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Source: https://durgical.com/en/general-pathology/rhinitis-sinusitis-pharyngitis-and-tonsillitis/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/rhinitis-sinusitis-pharyngitis-and-tonsillitis/