What are bloodshot eyes?
Bloodshot eyes describe a condition in which the whites of the eyes appear red. Bloodshot eyes occur when the blood vessels in the sclera (the white of the eye) dilate or swell. A variety of mild to serious diseases, disorders and conditions can irritate the blood vessels of the sclera and cause bloodshot eyes.
Bloodshot eyes are often due to mild conditions, such as eye fatigue, dehydration, and overuse of contact lenses. They can also be due to infections and allergic reactions. In some cases, a bloodshot or red eye or eyes can indicate an emergent condition that can lead to loss of sight, such as acute glaucoma or an eye injury.
Bloodshot eyes can begin suddenly and disappear quickly, such as when you have a mild allergic reaction to animal dander or dust. Bloodshot eyes can also develop with time and occur along with additional symptoms, which may be a sign of a more serious condition, such as a corneal ulcer or eye infection. Depending on the underlying cause, treatment for bloodshot eyes can range from rest and hydration to more extensive treatment, such as medication or surgery.
Because bloodshot eyes may be a sign of a serious condition, contact your medical professional about your symptoms. Seek prompt medical care if you have unexplained, persistent, or severely bloodshot eyes or if you are concerned about your symptoms. Seek immediate medical care (call 911) if you have bloodshot eyes accompanied by severe eye pain, loss of vision, or signs of anaphylactic shock (swollen tongue and throat, hives, and difficulty breathing).
What other symptoms might occur with bloodshot eyes?
Bloodshot eyes may occur with other symptoms, which vary depending on the underlying disease, disorder or condition. For example, bloodshot eyes due to dry eyes may be accompanied by irritation or eye pain. Bloodshot eyes caused by infection may include eye discharge, swelling, pain, and red eyelids. If you have other symptoms along with your eye symptoms, be sure to tell your health care provider. This information will help your doctor diagnose the reason for your eye symptoms.
Vision and other eye-related symptoms that may occur along with bloodshot eyes
Bloodshot eyes may accompany vision problems and other eye symptoms including:
Bleeding from the eye
Discharge from the eye
Eyelid swelling and inflammation
Increased sensitivity to light
Increased tear production (watery eyes)
Protruding or bulging eye(s) (proptosis)
Skin sores or pus-filled bumps on the eyelid
Allergy-related symptoms that may occur along with bloodshot eyes
Mild hives or swelling of a small or contained area of skin
Runny nose and nasal congestion
Sinus pressure or pain
Other symptoms that may occur along with bloodshot eyes
Bloodshot eyes may accompany other abnormal symptoms including:
Symptoms of sinusitis (facial pain and swelling)
Symptoms that might indicate a serious or life-threatening condition
In some cases, bloodshot eyes can indicate a serious or life-threatening condition, such as anaphylaxis, which should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have any of the following symptoms:
What causes bloodshot eyes?
Although bloodshot eyes can be caused by relatively mild conditions, such as dry eyes or the common cold, bloodshot eyes can also be caused by serious or life-threatening conditions, such as an anaphylactic reaction or acute glaucoma, both of which should be immediately evaluated in an emergency setting.
Infectious causes of bloodshot eyes
Bloodshot eyes can be caused by a variety of infections including:
Bacterial or viral conjunctivitis (inflammation of the eye surface)
Blepharitis (infected eyelash follicle)
Chalazion (inflammation of a blocked oil gland in the eyelid margin)
Common cold (viral respiratory infection)
Dacryocystitis (infected tear duct)
Iritis (inflammation of the iris)
Keratitis (inflammation of the cornea)
Orbital cellulitis (acute infection of the area surrounding the eye)
Scleritis (inflammation of the white of the eye)
Sinus infection or sinusitis
Stye (also called a hordeolum, which is an infected oil gland)
Uveitis (inflammation of the iris, choroid, and ciliary body in the eye)
Allergic causes of bloodshot eyes
Bloodshot eyes can be caused by mild to serious allergic reactions including:
Anaphylactic allergic reaction to any substance
Drug allergy, such as penicillin or codeine
Hay fever or allergic reaction from animal dander, dust, cosmetics, or pollen
Insect bite allergy such as bee sting
Traumatic and other physical causes of bloodshot eyes
Bloodshot eyes can arise from injury and other physical conditions including:
Contact lens use
Coughing or straining
Eye injury or surgery
Facial burn or other trauma
Foreign object in eye
Hyphema (bleeding inside the front of the eye behind the cornea)
Scratches on the cornea
Subconjunctival hemorrhage (broken blood vessel on the white of the eye)
Other causes of bloodshot eyes
Bloodshot eyes can be due to various other diseases, disorders and conditions including:
Blocked tear duct
Ectropion (turned-out eyelid)
Entropion (turned-in eyelid)
Keratoconus (cone-like cornea)
Pinguecula (yellowish, benign growth on the conjunctiva near the cornea)
Pterygium (fleshy, benign growth on the sclera that may extend onto the cornea)
Questions for diagnosing the cause of bloodshot eyes
To diagnose the underlying cause of bloodshot eyes, your doctor or licensed health care practitioner will ask you several questions related to your symptoms. You can best help your health care practitioner in diagnosing the underlying cause of bloodshot eyes by providing complete answers to these questions:
When did your symptoms start? Does the redness come and go or is it constant?
Have you had any change in your vision or visual disturbances?
Did you eat any foods or come in contact with any unusual substances preceding the onset of your symptoms?
Do you have any pain, shortness of breath, or other symptoms?
Provide your full medical history, including all medical conditions, surgeries and treatments, and family history. What medications and dietary supplements do you take?
What are the potential complications of bloodshot eyes?
Complications associated with the underlying causes of bloodshot eyes can be progressive. Because bloodshot eyes can be due to serious diseases, failure to seek treatment can result in complications and permanent damage. It is important to contact your health care provider when you have bloodshot eyes or other unusual symptoms that persist or become worse with time. Once the underlying cause is diagnosed, following the treatment plan outlined by your doctor can help reduce potential complications including:
Loss of the eye and orbital contents.
Loss of sight (blindness)
Spread of infection to other parts of the body including the blood