What is Periorbital Edema ?
Periorbital edema is usually a reaction or a symptom. It can represent many issues and will be treated by various forms. It can represent the beginning, or the extension of various disease processes.  It is extremely important to be aware of all the possibilities and rule out any thing that could be critical for the patient. For example periorbital edema could be difficult to diagnosis out but with the proper equipment and knowledge this can be done. 
This article will discuss the periorbital anatomy in order to better understand where the edema may be coming from. Also discussed will be possible causes, risk factors, treatments, diagnosis options and of course patient education.
Image 1. In this image you can see the periorbital edema is in both eyes but is server in the patients left side.
Image source – ncbi.nlm.nih.gov
Understanding anatomical positioning is always important when considering a proper diagnosis. Here we will discuss the orbital septum, the lachrymal system and the anatomy of the eye lid.
The orbital septum lies between the periosteum and the orbicularis oculi muscle. It fuses to the upper and lower lids and part of its function is to prevent the spread of infection from one eye to the other. 
The lacrimal system is of utmost importance to the health of the eye. It includes multiple parts, which assist in drainage. The parts of the lacrimal system are the lacrimal duct and the lacrimal sac. Interestingly the eye generally will produce 10ml of tears each day. 
The eyelid has a few areas of interest when discussing periorbital edema. The upper and lower eyelids includes various layers which are muscle, fatty tissue, skin and conjunctiva.  Each of these layers can be attributed to the cause of periorbital edema. The lower eyelid also has each of these layers. The specifics of the skin around the eyelid can be of concern for edema.
It is noted as the thinnest skin in the body.  The oculi muscles consist of protractors which are pretarsal, preseptal and orbital. Each of these have a very specific function and without one of them movement can be greatly compromised.
Image 2. In this image you can clearly see the superficial anatomy of the periorbital area. The measurements noted in this image are general but can be of great assistance if the patient’s first visit happens when they already present with edema and there is no base line noted.
Image source – plasticsurgerykey.com
Image 3. In this image you can clearly see the interior anatomy of the eye. It is clear when seeing this that there are many areas of the eye that could cause periorbital edema.
Image source – plasticsurgerykey.com
Although this list of causes is far from complete this article will state common and rare causes for periorbital edema. If you note that you have any type of swelling in or around your eyes this should be considered a medical emergency and you should seek medical attention. This section will discuss causes such as cellulitis in different areas of the eye, infections of other areas near to the eye, lupus, traumatic causes such as CPAP use and allergic reactions or side effects to medications.
The first and most commonly noted cause for periorbital swelling is cellulitis. It is simply an infection of the tissue surrounding the eye. This could be noted in any of the tissues noted in the above anatomy section. This issue can have various causes consisting of fungi, bacteria’s, and viruses. Infection in the tissues can even be a result of external trauma to the eye. 
There are various groupings of cellulitis. These are stated in the article (A 6-Year-Old Girl’s Eye Is Partially Swollen Shut) and consist of the following:
Group 1 – Preseptal cellulitis
Group 2 – Orbital cellulitis
Group 3 – Subperiosteal abscess
Group 4 – Orbital abscess
Group 5 – Cavernous sinus thrombosis 
Another common cause for periorbital edema can be infections in areas surrounding the eyes. These infections include and are not limited to respiratory tract infections such as sinusitis. These infections usually are caused by staphylococcous aureus. 
A type of infection that is part of the eye is lacrimal infections. Again as noted in the section on anatomy it is obvious to why this type of infection could cause irritation and swelling in the periorbital area. This resulting inflammation can be referred to as blepharitis or inflammation of the eyelids.
The canaliculi and the lacrimal glands can also be found in the Images noted in the section of anatomy. These areas can also get inflamed and when so is considered canaliculitis or dacryoadentis. 
As mentioned in the introduction of this section periorbital edema has been noted in patients with lupus erythematousus.
This is one of the reasons that all patients with periorbital edema should seek out medical attention. 
There is a leukemia treatment called Imatinib mesylate which has also been known to cause periorbital edema. This medication can also be used to treat gastrointestinal tumors. This is not the only medication that can cause these types of symptoms but it is a good example of periorbital edema being a common side effect of treatment. 
Other non-medical treatments such as use of CPAP for sleep apnea can also be a common cause of periorbital edema. The CPAP uses a face mask in which if not placed correctly can cause tissue damage to the periorbital area. Two patients developed bilateral, periorbital edema after initiating positive airway pressure (PAP) therapy with a full face mask.
The periorbital edema was more pronounced in the morning and would dissipate throughout the day. This phenomenon seemed to be correlated with the direct pressure of the full face mask, which may have impaired lymphatic and venous drainage. To test this hypothesis, each patient was changed to a nasal pillow interface with subsequent improvement in the periorbital edema.
Two patients developed bilateral, periorbital edema after initiating positive airway pressure (PAP) therapy with a full face mask. The periorbital edema was more pronounced in the morning and would dissipate throughout the day.
This phenomenon seemed to be correlated with the direct pressure of the full face mask, which may have impaired lymphatic and venous drainage. To test this hypothesis, each patient was changed to a nasal pillow interface with subsequent improvement in the periorbital edema. 
Image 4. This image shows two examples of periorbital edema caused by CPAP use.
Image source – ncbi.nlm.nih.gov
As a very rare case here in the image bellow you can see periorbital edema caused by substances contacting the eye. In this situation a fruit juice entered the eye of the patient causing inflammation. 
Image source – ncbi.nlm.nih.gov
Sulfite is commonly used in pharmaceuticals as a preservative. We report a unique clinical presentation of localized periorbital edema on the left eye after administration of sulfite-containing dexamethasone. The patient’s sulfite sensitivity was confirmed by sulfite oral provocation test: periorbital edema on the same site developed after ingestion of 200 mg sodium bisulfite. She was non-atopic and did not complain of any respiratory symptoms.
Allergy skin prick test with 100 mg/ml sodium bisulfite showed a negative result. She also has aspirin-sensitive urticaria which was confirmed by oral provocation test. In conclusion, sulfite can induce a localized periorbital edema, an uncommon manifestation in sensitive patients. Further investigations are needed to clarify the pathogenetic mechanisms.
Sulfite is commonly used in pharmaceuticals as a preservative. We report a unique clinical presentation of localized periorbital edema on the left eye after administration of sulfite-containing dexamethasone. The patient’s sulfite sensitivity was confirmed by sulfite oral provocation test: periorbital edema on the same site developed after ingestion of 200 mg sodium bisulfite.
She was non-atopic and did not complain of any respiratory symptoms. Allergy skin prick test with 100 mg/ml sodium bisulfite showed a negative result. She also has aspirin-sensitive urticaria which was confirmed by oral provocation test. In conclusion, sulfite can induce a localized periorbital edema, an uncommon manifestation in sensitive patients. Further investigations are needed to clarify the pathogenetic mechanisms.
Some risk factors of periorbital edema can be from external lesions such as bug bites, surgical procedures, oral procedures, and trauma. Also various disease processes could be known risk factors such as asthma, neutropenia, nasal polyposis and varicella. 
The treatment for periorbital edema will always depend on the cause or specific risk factors noted.
Thanks to the vaccine against Haemophius influenza there has been a notable decrease in bacterial orbital cellulites. Interestingly this suggest that influenza was a notable cause for bacterial orbital cellulites.
In the case that the periorbital swelling is from bacterial causes antibiotic therapy must be started to battle the infection. Depending on the other symptoms there may also be various other treatments given with antibiotics for patient comfort and faster healing. For example if the swelling includes abscess there may be need for surgical drainage. 
As mentioned before any type of periorbital swelling or edema should be considered as an emergency and medical treatment should be considered quickly. It is not easy to recognize the cause or source of the swelling and only a trained medical professional should make these decisions. 
Most treatment for types of periorbital edema such as cellulitis can be treated medically and do not need surgical treatment when found early. 
Diagnosis is done upon physical examination. Elevated temperature can be a symptom of infection. Other symptoms that will be checked for include pain, swelling, and blurred vision. The examiner will also be checking for any foreign objects.
In the case in which foreign objects may be found they will start the process of removing them. Each part of the fore mentioned anatomy will be reviewed and examined, for example the upper and lower eyelids, the lacrimal system as well as the upper respiratory tract. 
Patients should always be directed to medical attention when there is periorbital swelling noted. In the case of surgical treatment the patient will need to be instructed about bandage or eye patch changes. Patients should be informed of signs of infection such as swelling, heat, redness or pain. 
- Preseptal Cellulitis Updated: Jun 16, 2016 Author: Geoffrey M Kwitko, MD, FACS, FICS; Chief Editor: Edsel Ing, MD, FRCSC http://emedicine.medscape.com/article/1218009-overview
- A 6-Year-Old Girl’s Eye Is Partially Swollen Shut Ravi Shah; Amit R. Bhatt, MD; Charlene Crockett, MD; Charity H. Grannis, MD; Kimberly G. Yen, MD August 14, 2015 http://www.medscape.com/viewarticle/849311
- Periorbital Infections Updated: Nov 22, 2016 Author: Bobak Zonnoor , MD; Chief Editor: Gil Z Shlamovitz, MD, FACEP http://emedicine.medscape.com/article/798397-overview
- Periorbital edema as initial manifestation of chronic cutaneous lupus erythematosus, Samar Erras,1,& Laila Benjilali,1 and Lamiaa Essaadouni1, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3428177/
- Periorbital edema secondary to imatinib mesylate, Collin M McClelland, George J Harocopos, and Philip L Custer, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2874269/
- Periorbital swelling: the important distinction between allergy and infection P W A Goodyear, A L Firth, D R Strachan, M Dudley, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1726299/pdf/v021p00240.pdf
- Periorbital Edema Secondary to Positive Airway Pressure Therapy, F. Dandekar, 1 , 2 M. Camacho, 3 J. Valerio, 3 and C. Ruoff 3 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4342174/
- Keratoconjunctivitis and Periorbital Edema due to Ecballium elaterium, Dimitrios Brouzas,* Mariana Oanta, Eleni Loukianou, and Marillita Moschos1st. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3331881/
- Localized periorbital edema as a clinical manifestation of sulfite sensitivity. H. S. Park and D. Nahm, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3054089/pdf/8878807.pdf