Infected salivary gland (sialadenitis)

Red flags

• Abscess of the salivary glands may rarely progress into the deep neck spaces as a parapharyngeal abscess or Ludwig’s angina.

• Lower motor neurone facial nerve palsy with parotid swelling is usually not a sign of infection but rather one of a malignant tumour.

Why is this important?

The major (paired) salivary glands are the parotids, submandibulars and sublinguals, with numerous minor salivary glands throughout the oral cavity.  An acutely obstructed salivary gland causes a painful swelling which frequently presents to ENT.

When to involve the ENT registrar

• If infection has progressed to deep neck spaces and is compromising the airway.

• If patient is in septic shock

Who to admit

• Patient with a tender mass in the parotid or submandibular region that has not resolved with a one-week course of oral antibiotics

• Spreading overlying cellulitis

• Abscess formation (tender, warm and fluctuant swelling) over salivary gland areas

• Patients who cannot eat and drink

• Patients with evidence of sepsis

Assessment and recognition

Infections are commoner in the parotid (parotitis) and submandibular glands (submandibular sialadenitis). Elderly or disabled patients tend to have poorer oral hygiene and get dehydrated, despite the best efforts of carers, and they are at higher risk.

Most salivary gland infections settle with medical management. This includes adequate oral hygiene and hydration. Oral antibiotics are sufficient.

Some submandibular swellings may be abscesses or lymphadenitis due to dental pathology: always ensure dental examination and imaging have been undertaken to rule out a tooth abscess.

Patients with repeated salivary gland infections may have an underlying cause (see below), which will require further investigation.

A thorough history of duration, onset and nature of infection is vital. Patients usually complain of swelling, dry mouth, foul taste in the mouth and difficulty in eating and drinking. Pay good attention to co-morbidities and medications as these could be related to the underlying pathology.

Parotitis presents with a well-demarcated tender swelling in the preauricular region.  Discoloured saliva may be seen at the parotid duct orifice.  Onset may be insidious and due to ascending infection, viral infection or dehydration and "sludge" in the parotid duct.

Submandibular sialadenitis presents with sudden-onset swelling and pain in one submandibular gland, usually due to stone impaction.  This can occur transiently in patients with stones and strictures, but in established sialadenitis the gland remains swollen and becomes more and more painful.  Eating and drinking increase salivation and so make the symptoms worse.

Causes of salivary gland swellings

• Viral causes – Mumps, Coxsackie, Parainfluenza, Influenza A

• Bacterial causes – staphylococcus aureus, anaerobic bacteria

• Stones/calculis (sialolithiasis) - most common in submandibular glands.

• Chronic scarring and strictures (sialectasis)

• Benign and malignant tumours

• Granulatomous conditions - Sjogren’s syndrome, Sarcoidosis, Wegeners granulomatosis

• HIV-related lymphocytic infiltration (usually parotid gland)

• Medical causes – chemotherapy agents and radiotherapy (controversial!)

Examination of the neck and oral cavity is vital. This includes bimanual palpation of the floor of the mouth in submandibular swellings, and trying to express pus from the ducts.

Immediate and overnight management

If patient is otherwise well:

• Encourage supra-normal fluid intake and gland massage

• Discharge with analgesia and oral antibiotics, ensuring adequate cover for anaerobes: follow your local/Trust protocol.

• Advise the patient to return to A&E if their symptoms worsen

If patients meet the criteria for admission:

• IV access, bloods (including cultures if temp >38) and IV hydration

• Start antibiotics, ensuring adequate cover for anaerobes: follow your local/Trust protocol

• Encourage supra-normal oral hydration if tolerated and oral hygiene: this has to be stressed to the patient and/or their carers

• Citrus fruits / drinks or other forms of sialogogues can help promote salivary outflow to encourage expulsion of pus or stones

• Some patients attempt milking the duct for stones but this is painful

Further management

An ultrasound may requested to rule out abscess, confirm the presence of a stone, or if the diagnosis is unclear.

If there is an associated collection or deep neck space infection, this may require urgent surgical drainage.

Depending on the underlying cause, patients may undergo sialoendoscopy or sialography. This is usually on an outpatient basis once the immediate infection has settled.

Page last reviewed: 1 December 2022