Toxic Keratoconjunctivitis from Milkweed (Asclepias tuberosa) Exposure in a Contact Lens Wearer.

BACKGROUND: Toxic keratoconjunctivitis from plant exposure is a rare but potentially vision-threatening condition. Milkweed (Asclepias tuberosa) contains cardiac glycosides that disrupt corneal endothelial pump function, resulting in acute corneal edema and rapid vision loss. This entity is frequently misdiagnosed as benign conjunctivitis in the emergency setting.

CASE REPORT: A healthy adult presented with sudden visual loss and corneal haze hours after gardening. She had been wearing contact lenses and reported handling milkweed plants. An initial evaluation at an outside emergency department (ED) was unrevealing, and she was discharged with a diagnosis of conjunctivitis. She returned to the ED with worsening symptoms, including vision limited to motion detection. On further questioning, exposure to A. tuberosa was identified. Examination revealed corneal haze with a small abrasion. She was treated with corticosteroids and antibiotics, resulting in rapid improvement. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Milkweed-induced toxic keratoconjunctivitis is a rare but important cause of corneal edema and acute vision loss. A thorough exposure history is critical to diagnosis. Early initiation of corticosteroids may accelerate recovery.