What is it?
Cellulitis is infection advancing by spreading through the soft tissues. It differs from an abscess in its edge and in how it feels: an abscess collects at a single point, gives a wave under your finger when pressed and can be drained; in cellulitis the swelling is firm, hot and it is not clear where it ends. The two can also be present together in the same person.
The source of facial cellulitis is most often a tooth. Untreated deep decay kills the nerve of the tooth, an infection forms at the root tip, and that infection breaks through the bone into the soft tissue. Starting from an upper tooth, it tends to advance towards the cheek, the upper lip and under the eye; starting from a lower tooth, towards the edge of the jaw and under the jaw.
What decides matters is not the size of the swelling but the direction and speed with which it advances. Swelling that reaches the eyelid concerns the tissues around the eye, while swelling that travels down the neck concerns the spaces next to the windpipe. Once a high temperature, shivering, an inability to open the mouth and difficulty swallowing are added, treatment is not carried on as an outpatient.
Signs
You will not necessarily have all of these at once.
Why does it happen?
- 01
Deep decay and a dead tooth nerve
When decay reaches the nerve of the tooth, the pulp loses its vitality. The pain may stop after a while; that is not healing, it means the infection has moved to the root tip, and this is the most common way the picture starts.
- 02
Root tip infection breaking through the bone
Infection building up at the root tip opens into the soft tissue where the jaw bone is thin. This crossing most often turns into obvious facial swelling within a short time.
- 03
Where the root tip sits in relation to the muscle attachment
Whether the swelling goes to the cheek, under the eye or under the jaw is decided by where the root tip sits in relation to the muscle attachment line. Two infections of the same size can therefore show up in different places.
- 04
Silencing the pain without touching the source
Quietening the symptoms with painkillers and antibiotics while leaving the tooth untreated allows the infection to advance silently. Repeated facial swellings are most often the result of that cycle.
How does it progress?
- 1
Swelling limited to around the tooth
The swelling is in the gum and in the groove between the lip and the tooth. Tapping on the tooth hurts, and the shape of the face is not yet altered.
- 2
Crossing into the tissues of the face
The cheek or the edge of the jaw swells, and the skin turns red and feels hot. The edge of the swelling is lost and the mouth starts to open less far.
- 3
Advancing towards the eye or the neck
The lower eyelid may swell so that the eye opening narrows, or the swelling may travel from under the jaw down into the neck. At this stage treatment is planned in hospital.
- 4
Effects on your general condition
A high temperature, shivering, a faster pulse and marked weakness are added to the picture. Antibiotics through a drip, imaging and surgical drainage come onto the agenda.
How is it treated?
In facial cellulitis two things run together: getting rid of the source and antibiotic treatment. An antibiotic on its own is most often not enough; it may ease the pain and the swelling for a while, but as long as the tooth at the source stays where it is, the picture can be expected to come back. Work on the source is root canal treatment or extraction, depending on the state of the tooth, and any collection of pus needs to be drained.
How widely it has spread decides where treatment is carried out. If the swelling is limited, the mouth opens far enough and there is no high temperature, the work can be done as an outpatient with a review the next day. If the area around the eye or the neck is involved, if the mouth will not open, if swallowing is difficult, if there is a high temperature or an illness that lowers your resistance, then admission to hospital, antibiotics through a drip and, where needed, drainage in theatre are required.
The dental clinic's role in this picture is to find the source, take on the treatment inside the mouth and not delay the referral once the spread crosses that line; treatment as an inpatient is the hospital team's work. If things are going well, the first thing to expect is not that the swelling gets smaller but that it stops advancing. Shrinking usually starts later.
- If the swelling has reached your eyelid, or you are struggling to open your eye
- If your vision is blurred or double, or your eye movements are restricted
- If you cannot open your mouth two fingers' width, or you are struggling to swallow
- If the swelling is growing within hours along with a high temperature and shivering
How is it prevented?
- Do not count a tooth whose pain stopped on its own as sorted; have it checked.
- Finish a root canal treatment that was left halfway rather than waiting months with a temporary filling.
- Note the time the facial swelling started and where its edge was; whether it advances is what decides the next step.
- Do not start and stop antibiotics on your own decision; when the source is left untouched, the symptoms can come back.
Frequently asked questions
- Are an abscess and cellulitis the same thing?
- They are not the same. An abscess is pus collected in a defined space and it can be drained; in cellulitis the infection spreads between the tissues, the swelling is firm and its edge is unclear. The approach differs for that reason: in one, drainage comes to the front; in the other, stopping the spread and getting rid of the source take priority.
- The swelling has gone down, can I leave the tooth untreated?
- The swelling going down does not mean the source has closed off. When the infection at the root tip stays where it is, the symptoms can be expected to return after a quiet spell, and each time they may spread over a wider area. That is why treatment of the tooth at the source is planned even after the swelling has settled.
- How is it different from Ludwig's angina?
- In facial cellulitis the swelling is most often on one side and is seen on the outer surface of the face, on the cheek, under the eye or along the edge of the jaw. In Ludwig's angina the area involved is the floor of the mouth: the swelling is on both sides, the tongue is pushed up, and speech and swallowing are upset. Both can start from a tooth; as far as the airway goes, the second causes trouble earlier.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.