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What is causing this unilateral facial swelling

This man presented with a very swollen – but only mildly painful – face. Dr Mike Wyndham describes how he came to the right diagnosis


The patient

This 35-year-old patient came in with a facial swelling, clutching a picture of the swelling two days previously, in which it was slightly worse.

Either way, it looked extremely uncomfortable although he insisted it was only mildly tender.

He said this was the first time it had happened, that he had an excellent dental record and the problem was ‘out of the blue'. He had a clear medical history and had never smoked.

First instinct

There was certainly a large swelling on the side of the face. He felt well and was apyrexial. Clinically, it was the parotid gland. Surprisingly, when I pressed on it, there was only mild tenderness. Inside the mouth, the parotid duct looked prominent but there was no pus visible. There was no evidence of a facial nerve palsy.

Differential diagnosis

• Parotid tumour

• Stone obstructing the parotid gland

• Mumps

• Bacterial parotitis

Parotid tumours, on average, will develop between the age of 30 and 70 years. They are generally painless and unilateral. The age fitted for development and so did the fact that it was on one side. But it was causing some pain.

Stones occur most commonly in the submandibular glands, perhaps because they produce thicker saliva. But they can occur in the parotid and may cause pain when there is obstruction to drainage. if redness and increased swelling develop, it may suggest infection. Well, there was no redness, which suggested against infection, but a stone was definitely possible as there was pain and enlargement.

Mumps usually presents with headache and fever before any parotid gland change occurs. The swelling may be unilateral. The Health Protection Agency's website confirms that the number of reported cases has risen dramatically in the first six months of this year. The factor against it being mumps was the lack of constitutional upset.

Bacterial parotitis presents with pain and fever. Chewing food will make the gland feel more painful. If the gland is infected then it will be very tender to touch. Massaging the gland may produce pus from the duct. It may be associated with poor oral hygiene. In this patient's case, his oral care looked exemplary, there was no pus draining and he was in good health.

The hidden clue

It was going to be tricky to differentiate between the ‘cold causes' of parotid swelling in the consulting room. The infective causes seemed unlikely. But one important question to answer when a calculus is being considered is whether the gland is constantly the same size. The patient helped me out here by mentioning that he had noticed that when he was eating, the swelling seemed to increase and then 30 to 60 minutes after a meal it appeared to shrink down.

Getting on the right track

This variation in swelling made incomplete obstruction by a stone the most likely diagnosis.

I referred him to see a facio-maxillary surgeon but within a week the swelling had completely gone. Presumably, he has passed the stone.

Dr Mike Wyndham is a GP in Edgware, north London

Do you have an unusual case – with a clinical photo – that would make a good Snapshot Diagnosis? Contact deputy editor Adam Legge at or call 020 7921 8097

Unilateral facial swelling

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