One Sided Facial Swelling (Swollen Face on One Side)

Facial Symmetry

The human face is roughly symmetrical meaning that the vertical half on one side closely matches the other side. It most people it is not a mirror image but very similar. When there is a marked difference between one side of the face compared to the other then it is known as asymmetry. The size and shape of the face of determined by a number of factors, mainly genetics, body weight, general health and age. The structure of the human face is determined by the size, shape and quantity of :

  • skull bones (cranium and jaw)
  • facial muscles
  • subcutaneous fat
  • thickness and tautness of the skin

The orientation of the jaw (mandible) in relation to the cranium may also contribute to the shape of the face. Symmetry also applies to the eyebrows, eyes, nose, lips and ears.

Enlarged Side of the Face

Although it is known that the face is symmetrical, there is one side that is slightly larger then the other. This is normal and usually not noticeable unless the face is examined closely. Most people will know which side of their face is slightly larger than the other but it is not noticeable to even  close friends and family without careful scrutiny.

Sometimes, however, the enlargement of one side of the face reaches a point where it is clearly evident and even if it does not cause any other symptoms, it can cause psychological stress.  One sided facial swelling may occur with a growth in the bone or soft tissue, accumulation of fluid, muscle enlargement, skull bone and particularly jaw displacement compared to the other side of the face. Most of these scenarios are considered to be abnormal and facial asymmetry in these instances needs to be investigated further to identify the cause and corrected. Some of these causes can be potentially life threatening, like a malignant tumor, whereas in other cases it may be uncomfortable but will not lead to severe medical complications.

Why does only one side swell?

The most common causes of one sided facial swelling is a result of inflammation. This is often referred to as soft tissue swelling, although it may involve the bone to some degree as well. In most instances the inflammation is a result of an injury to the face but the inflammation can also arise with infections and allergies. Less commonly there may be one sided swelling of the face due to abnormal tissue growth like a tumor which may either benign (non-cancerous) or malignant (cancerous)

When there is one sided facial swelling, it simply means that the tissue on the enlarged side is affected. Apart from the tissue, each side of its face has its own blood, nerve and lymphatic supply. Therefore a condition that affects these structures on one side will lead to swelling only on that side. If the condition is systemic, or  generalized, then both sides may be swollen simultaneously.

Causes of One Sided Facial Swelling

It is important to consider several factors when evaluating the cause of facial swelling which may provide a better indication of the cause.

1. Did the facial swelling start suddenly or develop gradually?

2. Is the affected side painful, tender, numb or experiencing other abnormal sensations?

3. Is the enlarged side hard, soft, spongy or firm?

4. Is the one sides facial swelling affecting speech, breathing, eating or chewing, sense of taste or smell, size of the eyes or eyelid movement?

5. Is the facial swelling isolated to the cheek or extending upwards to the forehead or downwards to the neck?


The most common cause for facial swelling that tends to occur very rapidly and is usually just temporary is an injury to face. In these cases, the cause can be identified to a specific incident. Trauma to the face may occur with :

  • Blow to the face, like during an assault.
  • Car accidents
  • Falls
  • Following dental surgery or other surgical procedures to the face.
  • Insect bites and stings
  • Chemical burns
  • Severe sunburn on one side
  • Fractures to the cranium or jaw

The enlargement in these cases is due to fluid accumulation as a result of inflammation. It is the body’s ways of protecting tissue against injury. The blood vessels become leaky allowing excess amounts of fluid from the bloodstream to enter into the tissue spaces. Usually there is also heat of the area, redness, tenderness or pain. If a blood vessel is ruptured due to trauma, there may be an accumulation of blood in the tissue. This is known as a hematoma.


A number of microorganisms can cause an infection on one side of the face. This may be isolated to the superficial layers like the skin and subcutaneous fat, or involve deeper tissue such as the muscle and even extend into the bone. It may be caused by viruses or bacteria which are the most common pathogens, or fungi and other types of parasites. The different types of infections that may cause one sided swelling of the face includes :

  • Cellulitis. If this extends to the area around the eye then it is known as orbital cellulitis.
  • Abscess – tooth, gingival (gum), peritonsillar.
  • Sinusitis which is an infection of the paranasal sinuses.
  • Osteomyelitis which is an infection of the skull bone or jaw
  • Parotitis which is an inflammation of the parotid gland most commonly caused by an infection like mumps.
  • Lymphadenitis which is the inflammation of lymph nodes.
  • Eye and eyelid infections like conjunctivitis, keratitis, stye (hordeolum) and blepharitis. The swelling is usually over and around the eye but may extend onto the cheek and up to forehead in severe cases.


There are a number of allergic reactions that can cause one sided facial swelling. The most important and severe is anaphylaxis (anaphylactic reactions) which can be life threatening without immediate medical attention. It usually causes bilateral swelling (entire face swollen). Other allergic causes includes :

  • Allergic conjunctivitis
  • Allergic rhinitis (hay fever)
  • Drug allergies
  • Allergies to insect bites and stings
  • Allergies to various substances that may be used in facial creams, cosmetics, implants for cheek augmentation and sometimes dental materials.

Muscle Problems

The facial muscles, like the large masseter muscle, gives the cheeks definition and problems with these muscles can alter the shape and size of the face.

  • Atrophy (shrinking) of the muscle on one side as may be seen with partial or complete muscle paralysis (like in Bell’s palsy).
  • Hypertrophy (enlargement) of the muscle on one side with clenching on one side or chewing only on one side.

Sometimes facial spasms associated with certain nerve and muscle diseases can cause a facial distortion.


Tumors, either benign (non-cancerous) or malignant (canerous) may arise in any of the following tissues :

  • Muscle
  • Bone
  • Subcutaneous fat
  • Skin
  • Connective tissue
  • Lymph nodes or vessels

Less frequently, a tumor or the blood vessels or nerves may also be responsible for the one sided swelling.

Other causes

Most of the other causes a systemic, meaning that it affects the entire body or several systems of the body simultaneously. It is unlikely to cause one sided facial swelling but instead swelling of the entire face. Nevertheless it is worth considering these conditions as a possible cause of one sided facial swelling.

  • Cushing’s disease
  • Kidney failure
  • Heart failure
  • Liver failure
  • Serum sickness
  • Malnutrition
  • Obesity
  • Ashley

    For about 7 months now, the left side of my face/cheekbone has been swollen. I experienced sun damage on this side of my face from a recent trip in Cancun. I have gone for an ultra sound, Ct scan, and even an MRI scan on it and nothing shows. I have been to the dentist, ENT, dermatologist, and even a nuerologist and no one can seem to figure this out. Any chance you know what this can be?

  • Mitzi K.

    My husband and I went on a walk yesterday and suddenly his upper lip and cheek area swelled up on his right side and was numb. There is no pain. I gave him an OTC antihistamine and an ice pack which relieved the symptoms somewhat. By the end of the day yesterday it was almost normal (95%). But when he awoke this morning it was back but not as severe. He has not had dental work, changed medication, or introduced something new to his diet. Any ideas?

  • Gargi jain

    The left side of my mother’s face started swelling which includes cheeks and eyes.There is no pain but a little bit itching is there. We consulted our doctor but he said there is nothing. There is no injury too. Now The swelling is shifting to the right side of the face ,i.e,the eyes . She has thyroid and blood pressure. What should be done?

  • maryam

    After a medical facial one side of my face was swallon i went to the doctor she said it a tissue damage than she said it will get better with time but its been 2 years now but nothing happened what should i do

  • Hi Ashley. As you can see from the article above there are many possible causes and not all causes have been discussed here. Sun damage could cause superficial swelling but it should have resolved within a few weeks. A persistent swelling (and assuming that you are not talking about a hard enlargement) can sometimes occur with certain cardiac conditions, and more so after wakening. Of course, this is just one possibility and it is difficult to say for sure through an online platform. The fact that you have seen so medical specialists who have not as yet diagnosed a possible cause is baffling, and we could not be much more help in this regard.

  • HI Mitzi. An allergic reaction is a possibility since he could have been exposed to some allergen when out for the walk that he does not usually encounter. From the location and sudden onset, an allergy seems even more likely, in addition to the fact that he responded to antihistamines. This definitely needs to be followed up with your family doctor. The reaction may have been relatively mild this time but there is no way of saying that it cannot be severe on future encounters. Your family doctor may also want to refer him to an allergist at some point so getting professional medical attention is important. It is difficult to say what could have caused this from your report and further diagnostic tests are necessary.

  • Katie Stewart

    I woke up this morning, now 20 hours ago, to the left side of my face swollen. It’s lower on my face, it almost looks saggy. There’s no swelling on the inside of my mouth, no pain, I’ve got no rash or fever or any cold symptoms. It’s spongy feeling and has gone up and down in size all day but not once returned to normal.
    I have hyperthyroidism and Graves’ Disease.

  • Hi Gargi. FIrstly a problem with the skin and the tissue just underneath would be the first consideration, such as the case with angioedema although she does not appear to have typical symptoms. There are several possible conditions that could cause this like contact dermatitis which is an irritation or allergic reaction of the skin to some substance that is making contact with it. Given your mother’s history, it may also be a good idea to have a cardiovascular condition. Swelling of the face can occur in some people with heart failure. As you can see from the article above there are many possibilities. You should consult with another doctor for a second opinion.

  • Hi Maryam. There could have been deep tissue injury with this procedure and usually the swelling subsides within a few days to weeks at most. SInce there is ongoing swelling, you need to have this checked. Consult with a dermatologist. While this may be related to teh procedure that you underwent, it is also possible that this is an entirely separate condition that is causing the swelling. It is difficult to say for sure but 2 years is a very long time to have waited for this to resolve.