Deep neck infection and Ludwig angina !
A deep neck infection is a spreading infection or abscess between the layers of the neck; Ludwig angina, in the floor of the mouth, can block breathing.
Updated 2026-10-29
Structures involved
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- Cervical fascia
- Mylohyoid
- Pharynx
- Submandibular gland
- Carotid sheath
- Internal jugular vein
- Tongue
- Palatine tonsils
In embryology
Why it happens
- Patterns of acute inflammation: serous, fibrinous, purulent, abscess, ulcer
- Outcomes of acute inflammation: resolution, abscess, scar or chronic inflammation
What it is
A bacterial infection, cellulitis or abscess, in the spaces between the deep layers of cervical fascia. Ludwig angina is a rapidly spreading cellulitis of the floor of the mouth that can block the airway.
Who gets it
Odontogenic infections are now the most common source in adults and tonsillar infections in children. Diabetes and poor dental access are common backgrounds.
Causes
- Odontogenic infection, especially of the second and third mandibular molars (main cause of Ludwig angina)
- Tonsillitis, pharyngitis and peritonsillar abscess
- Salivary gland infection, trauma, foreign bodies and injection drug use
- Usually polymicrobial: streptococci, staphylococci and oral anaerobes
Risk factors
- Poor dental hygiene and untreated caries
- Diabetes mellitus
- Immunosuppression
- Recent dental procedures
Pathophysiology
Infection spreads along fascial planes from its source into potential spaces of the neck. In Ludwig angina, infection from lower molars whose roots lie below the mylohyoid line enters the submandibular and sublingual spaces on both sides and pushes the tongue up and back. Spread to the parapharyngeal, retropharyngeal and danger spaces can reach the mediastinum or the carotid sheath.
Classification
- By space: submandibular (Ludwig angina), parapharyngeal, retropharyngeal, danger and prevertebral spaces
- Cellulitis versus abscess
Symptoms and signs
- Fever, neck pain and swelling
- Painful swallowing, drooling and muffled voice
- Trismus
- Firm, tender, woody swelling of the floor of the mouth with a raised tongue in Ludwig angina
- Neck stiffness or reduced neck movement
Diagnosis
- Clinical
- Airway assessment comes first; examination of teeth, pharynx, floor of mouth and neck.
- Tests
- Blood count, inflammatory markers, glucose, blood cultures and culture of drained pus.
- Imaging
- Contrast-enhanced CT of the neck (and chest if mediastinitis is suspected) once the airway is safe; ultrasound for superficial collections.
Differential diagnosis
- Peritonsillar abscess
- Epiglottitis
- Angioedema
- Cervical lymphadenitis
- Infected branchial or thyroglossal cyst
Goal of treatment
Secure the airway, control infection with antibiotics and drainage, and remove the source.
Treatment
- Acute
- Airway protection is the priority: close monitoring, and awake fibreoptic intubation or surgical airway (tracheostomy) when the airway is threatened.
- Medical
- Intravenous broad-spectrum antibiotics covering streptococci and anaerobes; corticosteroids are sometimes used to reduce swelling.
- Surgical
- Incision and drainage of abscesses and extraction or treatment of the infected tooth.
- Follow-up
- Intensive care monitoring when the airway or circulation is at risk.
Complications
- Airway obstruction
- Descending mediastinitis
- Sepsis
- Internal jugular vein thrombosis (Lemierre syndrome)
- Carotid artery erosion
- Necrotising fasciitis
Prognosis
Good with early airway control, antibiotics and drainage. Mortality rises steeply with airway loss, mediastinitis or delayed treatment.
Prevention
- Timely treatment of dental infections
- Good oral hygiene and control of diabetes
Test yourself
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What is the most common source of Ludwig angina?
An odontogenic infection, usually of the second or third mandibular molars.
Which spaces are involved in Ludwig angina?
The submandibular and sublingual spaces on both sides (the submandibular space).
What is the first priority in a patient with suspected deep neck infection?
Assessing and securing the airway.
Which space connects the neck to the posterior mediastinum?
The danger space (between the alar and prevertebral fascia).
What is Lemierre syndrome?
Septic thrombophlebitis of the internal jugular vein after oropharyngeal infection, classically from Fusobacterium necrophorum.
Related conditions
- Dental caries
- Streptococcal pharyngitis
- Cervical lymphadenopathy
- Sepsis and septic shock
- Type 2 diabetes mellitus
- Peritonsillar abscess
- Periodontitis
- Sialolithiasis (salivary stones)
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Deep Neck Infections (StatPearls (NCBI Bookshelf), 2024); Ludwig Angina (StatPearls (NCBI Bookshelf), 2025).
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Representative model, for educational purposes only.
