Conjunctival provocation test (CPT), the confirming diagnostic test of ocular allergy, is underused by clinicians. We compared the diagnostic accuracy of CPT in daily practice using two different symptoms´ score systems recommended by the EAACI Interest Group on Ocular Allergy: ocular pruritus score (OPS) and 4 total ocular symptoms score (4TOSS).
Mixed grass pollen extract (LETI SL, Madrid, Spain) was used for CPT in 11 asymptomatic patients with persistent moderate-severe rhinoconjunctivitis due to grass pollen and 8 controls (4 healthy subjects, and 4 patients with D. pteronyssinus allergic rhinitis). The positive CPT criterion was 4TOSS ≥ 5, or OPS ≥ 2. Response to CPT evaluated by 4TOSS (pruritus, hyperemia, tearing, and chemosis) and OPS were compared with SPT results, the gold standard (SPT). The appearance of nasal and/or bronchial symptoms was also evaluated.
OPS had 100% sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and concordance with SPT (kappa index 1, p<0.001). 4TOSS had a high sensitivity (90.9%), specificity (100%), PPV (100%), NPV (88.9%) and concordance with SPT (kappa index 0.894, p<0.001). Thirty six per cent of cases with a positive CPT had a positive nasal response (4 total nasal symptoms score >5). No bronchial symptoms were detected. A significant negative correlation between serum Phleum-sIgE levels and grass pollen threshold CPT concentration was detected (Rho -0.918, p>0.001).
The results demonstrated that OPS system is a very useful parameter to assess the response to CPT in patients with moderate-severe allergic rhinoconjunctivitis in daily practise.