Differential Diagnosis for Itchy Eye without Vision Changes

• Single most likely diagnosis
  • Allergic conjunctivitis: This is the most common cause of itchy eyes, often associated with other allergic symptoms such as sneezing, runny nose, and nasal congestion. The absence of vision changes makes this diagnosis more likely.
• Other Likely diagnoses
  • Dry eye syndrome: This condition can cause itchiness, especially if the eyes are not producing enough tears or if the tears are of poor quality. It's common, especially in older adults or those who spend a lot of time looking at screens.
  • Blepharitis: Inflammation of the eyelids can cause itchiness, redness, and a gritty sensation in the eyes. It's often associated with poor eyelid hygiene or conditions like rosacea.
  • Contact dermatitis: An allergic reaction or irritation from substances like makeup, contact lens solution, or pollen can cause itchy eyes.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Acute angle-closure glaucoma: Although vision changes are typically present, in early stages or atypical presentations, patients might only experience eye pain and itchiness without noticeable vision changes. It's a medical emergency requiring immediate treatment.
  • Orbital cellulitis: An infection of the tissues surrounding the eye can cause pain, redness, and swelling, and while vision changes are common, they might not always be present early on. It requires prompt antibiotic treatment to prevent serious complications.
• Rare diagnoses
  • Phlyctenular keratoconjunctivitis: An inflammatory condition of the conjunctiva and cornea, often related to an allergic or immune response, which can cause itchy eyes among other symptoms.
  • Vernal keratoconjunctivitis: A seasonal allergic condition that affects the eyes, causing itchiness, redness, and sometimes vision problems, more common in children and young adults.
  • Atopic keratoconjunctivitis: Part of a broader atopic disease (like eczema), this condition can cause chronic itchy eyes, along with other ocular and systemic symptoms.