The potential for ocular allergic patients to have a site-specific antigen sensitisation was investigated using various diagnostic tests of allergen sensitivity in subjects with allergic conjunctivitis (AC: n= 135), vernal keratoconjunctivitis (VK: n= 20), rhinoconjunctivitis (n= 20) or rhinitis (N= 10). In the AC and VK patients, skin tests and conjunctival provocation tests (CPT) were performed, and the levels of specific IgE in serum and in tears were identified. A subgroup of 36 patients was also challenged with a nasal-specific provocation test (NPT). Results showed a poor correlation between skin test results and tear-specific IgE, and also between serum-specific IgE and tear-specific IgE in both AC and VK patients (K< 0.3). CPT and tear IgE were significantly correlated (K= 0.5) in the ocular allergic population. In patients with rhinoconjunctivitis or rhinitis, and in 10 normal subjects, results of CPT and NPT were in 100% agreement. Conversely, in patients with only conjunctivitis, little correlation was found between the results of CPT and NPT (K= 0.3). Tear-specific IgE was the only positive diagnostic sign of antigen sensitivity in 35% of VK patients and 30% of AC patients. These results suggest that the conjunctiva can be a uniquely sensitised target organ in allergic patients.