The conjunctival provocation test (CPT) is frequently used to not only identify the particular allergen causing the symptoms of allergic rhinoconjunctivitis, but also to assess the clinical effectiveness of allergen immunotherapy (AIT). As there is no agreement on its predictive usefulness, the goal of this article is to determine under what conditions the CPT can predict symptom intensity during allergy season after prior AIT. Three of four randomised controlled studies (RCTs) found a link between CPT reactivity and symptoms caused by natural allergen exposure following previous AIT. In addition, an RCT revealed that the CPT can identify early respondents four weeks following initiation of AIT which also show a benefit over the season. Another CTR indicated that the CPT may be used to identify individuals who are more treatable than others before the commencement of AIT.

A study of the literature led to the conclusion that the CPT is of predictive value and, if conducted according to a standardised Challenge Protocol using high-quality allergen extracts, may thus be used to evaluate the effectiveness of the AIT given.

Reference: https://journals.lww.com/co-allergy/Abstract/2018/10000/Conjunctival_provocation_tests__prediction_of.7.aspx

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