This patient is suffering from allergic conjunctivitis, caused by sensitivity to pollen, dander, mold, or by another allergen. Allergic conjunctivitis typically presents with pruritis, hyperemia, tearing, and eyelid edema bilaterally.
Allergic conjunctivitis is a common condition which affects 5-22% of the population. It is part of a systemic reaction to an allergen, most commonly pollen. Patients present with intense itching of both eyes, as well as redness, tearing, and edema. Many patients have other allergic symptoms as well, such as allergic rhinitis. It is usually not painful and not associated with photophobia.
Morrow and Abbott provide a thorough review of conjunctivitis, touching on the different etiologies, the approach to the diagnosis, and the treatment guidelines. Of note, they state that the diagnosis is typically clinical, but specify that patients who have severe inflammation or who do not respond to treatment should have bacterial cultures obtained. They also touch on the importance of unilaterality versus bilaterality of symptoms. While allergic conjunctivitis is almost always bilateral, viral and bacterial conjunctivitis tend to start in one eye and then progress to the other eye.
Wong et al. define allergic conjunctivitis as an IgE-mediated hypersensitivity reaction. They describe both pharmacological and non-pharmacological treatments for allergic conjunctivitis. Non-pharmacological treatments include eye hygiene (cool compresses, decrease eye rubbing, etc.) and avoidance of allergens. Pharmacological treatments include antihistamines, mast-cell stabilizers, and steroid drops.
Figure A shows the eye of a patient with allergic conjunctivitis with hyperemia of the conjunctiva, swelling of the eyelids and conjunctiva, and watery discharge. Illustration A depicts an algorithm for thinking about conjunctivitis. Following a series of targeted questions about specific symptoms, it helps differentiate allergic, viral, and bacterial conjunctivitis, as well as other more worrisome conditions.
Answer 1: Foreign objects in the eye are typically unilateral and painful. This patient's presentation is more consistent with allergic conjunctivitis.
Answer 3: Bacterial conjunctivitis a common condition and is associated with yellow-green purulent discharge.
Answer 4: Viral conjunctivitis is a common condition that is very contagious. Unlike allergic conjunctivitis, it begins unilaterally and then progresses to the other eye. It presents with watery discharge, hyperemia of the conjunctiva, and eyelid swelling. Although possible, allergic conjunctivitis is the more likely cause in this patient, as he presented bilateral, his predominant symptom is pruritis, and he has not had any sick contacts.
Answer 5: Corneal ulcers are often unilateral and extremely painful.
Morrow GL, Abbott RL. Conjunctivitis. Am Fam Physician. 1998 Feb 15;57(4):735-46. Review
PMID:9490996 (Link to Abstract)
Wong AH, Barg SS, Leung AK. Seasonal and perennial allergic conjunctivitis. Recent Pat Inflamm Allergy Drug Discov. 2014;8(2):139-53
PMID:25000933 (Link to Abstract)