Chemosis

An eye with a swollen region of the conjunctiva (front view).

An eye with a swollen region of the conjunctiva (mirror, side view).

Chemosis is the swelling (or edema) of the conjunctiva. In general, chemosis is a nonspecific sign of eye irritation. The outer surface covering appears to have fluid in it. Often, the eye area swells so much that the eyes become difficult or impossible to close fully. It is usually caused by allergies or viral infections, as well as eye rubbing. Chemosis is also included in the Chandler Classification system of orbital infections.^{[citation needed]}

Other causes of chemosis include:

• superior vena cava obstruction, accompanied by facial edema.
• hyperthyroidism, associated with Exophthalmos, periorbital puffiness, lid retraction, and lid lag.
• cavernous sinus thrombosis, associated with infection of the paranasal sinuses, proptosis, periorbital edema, retinal hemorrhages, papilledema, extraocular movement abnormalities, and trigeminal nerve sensory loss.
• cluster headache
• trichinellosis
• Systemic lupus erythematosus (SLE)
• angioedema

Treatment depends on the cause of the chemosis.