Conjunctival provocation test for the diagnosis of ocular hypersensitivity to chlorobutanol

Conjunctival provocation test (CPT) is a useful tool for the determination of the reagent in patients with allergic conjunctivitis. Our aim is to present an unusual reaction of ocular hypersensitivity to chlorobutanol by using this technique.

This case describes a 56-year-old woman who presented intense ocular pruritus and conjunctival hyperemia with each instillation of Colircusi Fluotest (Alcon, El Masnou, Spain). Skin tests and CPTs were considered.

Skin tests were all negative. CPTs were performed with commercially available ophthalmic products that were selected for their compositions. Chlorobutanol was presumed as the reagent through elimination. Positive CPT with purified chlorobutanol confirmed this hypothesis.

CPT performed with commercially available products can be a useful, accessible, and inexpensive technique to orient the diagnosis of suspected ocular hypersensitivity to a pharmacologic component. To our knowledge, this is the first report of ocular hypersensitivity to chlorobutanol.