Differential Diagnosis for Allergic Eyes

Single Most Likely Diagnosis

• Allergic Conjunctivitis: This is the most common condition associated with allergic eyes, characterized by symptoms such as itching, redness, and watery discharge, typically triggered by allergens like pollen, dust mites, or pet dander.

Other Likely Diagnoses

• Vernal Keratoconjunctivitis (VKC): A seasonal allergic disorder more common in children and young adults, presenting with intense itching, photophobia, and stringy discharge.
• Atopic Keratoconjunctivitis: Associated with atopic dermatitis, this condition involves the conjunctiva and cornea, leading to symptoms like itching, burning, and blurred vision.
• Giant Papillary Conjunctivitis (GPC): Often related to the use of contact lenses, GPC is characterized by the development of large papillae on the underside of the eyelid, leading to discomfort, itching, and blurred vision.

Do Not Miss Diagnoses

• Acute Angle-Closure Glaucoma: Although not directly an allergic reaction, it can present with red, painful eyes and should be considered in the differential due to its potential for severe vision loss if not promptly treated.
• Keratitis: Inflammation of the cornea that can be caused by infection or injury, presenting with pain, redness, and vision changes, which could be mistaken for an allergic reaction.

Rare Diagnoses

• Mastocytosis: A condition characterized by an accumulation of mast cells in various tissues, including the eyes, which can lead to allergic-like symptoms.
• Eosinophilic Granuloma: Part of the spectrum of Langerhans cell histiocytosis, it can rarely affect the orbit and present with proptosis, eyelid swelling, and other ocular symptoms that might mimic an allergic reaction.