1. Non-Washed Eyes

Thick fat from oil glands in inner eye corner may cause itchy eyes if not washed off in the morning. Sweat from the face or hands while rubbing eyes also cause itchy eyes.

2. Foreign Body

A small object or fly, falling in the eye usually causes intense itch and watery eye. Pulling the lower eyelid down, or inverting the upper eyelid up may help in location the object that can be then removed by a cotton stick. This also helps in in-turned eyelash.

3. Aggressive Fluids and Gases

Aggressive fluids like vinegar, acids, or solvents have to be removed from the eye immediately by rinsing the eye with lukewarm tap water. Rinsing also helps in itchy eyes due to smoke or other irritant environmental gases.

Salty sea water, shampoos, aftershave, cosmetic lotions, and creams coming into an eye are usually not dangerous, but rinsing the eyes helps to relieve itch.

Poisoning.

4. Common Cold, Flu, Sinusitis

In common diseases with runny nose and fever, eyes may itch due to increased tearing, or conjunctivitis.


5. Conjunctivitis (Red Watery Eye, or Pink Eye)

Conjunctiva is a thin translucent layer that covers the visible part of eye sclera and inner part of eyelids. When conjunctiva gets inflamed, its tinny blood vessels dilate thus causing appearance of red or pink eye. Other symptoms may include itchiness, blurred vision, sensitivity to light, increased tearing, and discharge. Condition is medically called conjunctivitis (3), common causes are:

  • Acute bacterial conjunctivitis. Newborn may get infected with Neisseria gonorrhoeae from infected vagina during delivery. Profuse purulent discharge appears in one or both eyes 3-5 days after delivery. In young sexually active adults, conjunctivitis can be transmitted by hand from infected genitals. Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae may cause conjunctivitis as part of respiratory, or skin infection. Treatment is with antibiotics by mouth or as eye-drops.
  • Chronic bacterial conjunctivitiscaused by Chlamidia trachomatis causes trachoma (mostly in undeveloped rural areas of the world), or inclusion conjunctivitis spread from genital infection. Treatment is with antibiotics. Chronic conjunctivitis may also appear in infected eyelidsor acne rosacea.
  • Viral conjunctivitis is often caused by Adenovirus, transmitted by fingers, medical instruments, or swimming pools. Itchy eyes and watery discharge are main symptoms. Treatment is with cold compresses applied over the eyes for 10-15 minutes several times a day. Herpes simplex or Herpes zoster may cause painful keratoconjunctivitis, that can be treated with antiviral drugs.
  • Allergic conjunctivitis is described below. Stringy translucent discharge is characteristic. Treatment is with antihistamines, anti-inflammatory drugs and corticosteroids.

6. Eyelid Disorders

A stye, chalazion, inflammation of the eyelid (blepharitis), or eyelid carcinoma can all irritate the eye. Causes of itchy eyelid.

Trichiasis (Greek trich- = related to hair; -iasis = related to eye) is anatomical mispositioned eyelash - an ingrown eyelash. The cause is often not known, but it can result from eyelid inflammation, conjunctival scar, injury, operation, or anatomical abnormality of the eyelash. Irritating eyelashes have to be removed with forceps, by electrolysis, or freezing (1).

Non-Complete Eyelid Closure. Loose connection tissue due to age, constant weeping, inflammation of eyelids or conjunctiva that left scars, injury, Bell’s palsy, eyelid surgery, or anatomical abnormalities may all result in drooping (out-turned), lower eyelid, and hence non-complete eye closure, that causes increased evaporation of tears and dry itchy eyes. In-turned eyelid causes the same problems.

7. Allergies

In allergies, both eyes are usually affected; eyes may be dry or wet. Eyes itch due to allergic inflammation of conjunctiva – a tinny pink membrane on the inner side of eyelids that connects the eyeball and eyelids. Other possible symptoms are runny nose, itchy lips, swollen face, hives on upper part of the body, and, in severe cases, difficulty breathing, fainting, and shock. Itchy eyes may be due to allergy to:

  • Pollens
  • Dust mites
  • Mold
  • Pet hair and dander
  • Foods (eggs, cow’s milk, soy, wheat, peanuts, tree nuts, fish, shellfish, etc.)
  • Medications
  • Cosmetics (shampoos, hair dyes, makeup)
  • Insect bites (bees…)
  • Household chemicals
  • Cockroaches
  • Contact lenses usually don’t cause eye allergies, but may aggravate allergies from other reasons

Therapy in Allergic Reaction

Antihistamines by mouth, nasal corticosteroid spray or eye-drops usually help in mild allergy (2). Prevention is in avoiding triggering substances, and washing eyes frequently. Most allergies disappear with time, but some (to nuts and seafood) may persist lifelong.

Eye-drops containing antihistamines should be avoided since they themselves may cause allergic reaction. Eye-drops with decongestants – substances that shrink vessels in conjunctiva – should be also avoided since vessels may become dependent on them and won’t shrink naturally after their prolonged use. Corticosteroid eye-drops may thin the skin on eyelids after prolonged use.


8. Dry Eyes (Keratoconjunctivitis Sicca)

Keratoconjunctivitis sicca is inflammation of cornea and conjunctiva, causing dry, itchy, and sometimes red eyes, blurred vision, and sensitivity to light. Excessive tearingoccurs when nerves in irritated dry cornea stimulate tear glands to produce excessive amount of tears. These excessive tears are watery and do not moist the eye properly, so the drying-tearing cycle may continue. Main causes are mentioned below.

Low Tear Production

Conditions with decreased tear production:

  • With age, especially in women after menopause, tear gland may decrease its tear production
  • Medications: isotretinoin, sedatives, diuretics, tricyclic antidepressants, antihypertensives, oral contraceptives, antihistamines, nasal decongestants, beta-blockers, phenothiazines, atropine, opiates (morphine)
  • Sjögren’s syndrome is autoimmune disease that affect all glands with external secretion, including tear glands, salivary glands, sweat and oil glands and glands in bronchi and gastrointestinal tract
  • Rheumatoid arthritis, vasculitis, systemic sclerosis, systemic lupus erythematosus (SLE), Wegener’s granulomatosis, sarcoidosis, tear gland tumors, and post-radiation fibrosis may all affect tear glands
  • Congenital disorders like alacrima, xerophtalmia, tear gland ablation, or sensory denervation  

Abnormal Tear Composition

Blepharitis, trachoma, rosacea, and vitamin A deficiency may result in dry itchy eyes due to to abnormal tear composition. Insufficient blinking during tasks that require high concentration, as reading, working with the computer result in reduced oiling of the cornea, and thus eye dryness.

Environmental Causes of Dry Eyes

Wind, sun, high altitude, air pollution and the dust are outdoor causes of dry itchy eyes. Indoor heating, air condition, smoking may cause dry itchy eyes and other symptoms of the “sick building syndrome”.

LASIK

LASIK or other refractive surgery may damage corneal nerves that stimulate tear secretion. Condition usually recovers after some time.

Contact Lenses

Soft contact lenses interfere with tear flow over the cornea, and may cause dry itchy eyes, especially after prolonged use. 

Pterygium Conjunctivae

Pterygium (4) is a small fleshy outgrowth from the cornea, usually appearing in the inner corner of the eye. It may be a result of chronic eye irritation, but exact cause is not known. If it causes symptoms, it can be surgically removed. 

Diagnosis of the Cause of Itchy Eyes

Most causes of dry eyes are obvious from the sufferer’s history. Eye examination can reveal problems with eyelids. In Schirmer’s test a strip of paper is stuck under the lower lids and amount of paper soaked with tears is measured after 5 minutes. Dermatologist may be needed to evaluate eventual eyelid disease.

General Treatment And Prevention Possibilities in Itchy Eyes

  • Sun glases, or special airlock seal eyeglasses may protect eyes against the wind, pollen and dust.
  • Avoid rubbing your eyes.
  • Remember to blink regularly, make regular pauses when reading or working with a computer.
  • Artificial tears help in dry eyes. Restasis eye-drops (cyclosporine in a castor oil) increase tear production. These should be not confused with “eye-drops against red-eye” that even worsen dry eyes.
  • Omega-3 fatty acids by adding salmon or sardines into the diet should be considered in dry eyes, when the lack of essential fatty acids is suspected.
  • Indoor air filters remove dust from the air, and humidifiers add moisture to air.
  • Temorary or permanent punctal occlusion. Openings (Latin puncta) through which tears flow from the eye into the nose cavity can be occluded with plugins, what prevents draining of tears out from the eye.
  • Medications by mouth: anti-nflammatory drugs, corticosteroids, antihistamines, or antibiotics by mouth to treat eventual eye or eyelid inflammation or infection.
  • Surgery procedure may be needed to correct eyelid abnormalities.
Further Reading:

 References:

  1. Trichiasis causes and treatment  (merck.com)
  2. Treating allergies in kids  (kidshealth.org)
  3. Conjunctivitis – causes, symptoms, and treatment  (aafp.org)
  4. Pterygium conjunctivae  (apagrafix.com)