Evaluation of plasma canine C-reactive protein concentrations in dogs with otitis media, healthy dogs and dogs with chronic otitis externa.

Background: Otitis is characterised by inflammation of one or more of the structures of the ear. At present, to confirm or exclude otitis media (OM), it is most often necessary to perform a computed tomography (CT) scan or magnetic resonance imaging. Inflammation is an immune defence response found in many conditions that can be detected and tracked by measuring biological markers of inflammation as the Canine C-reactive protein (CRP).

Objectives: The objective of this study was to determine whether CRP measurement is useful as an adjunctive diagnostic tool in dogs with otitis and whether elevated concentrations correlated with disease severity/presence of OM.

Animals: Twenty-four client-owned dogs were recruited over 1 year.

Materials and methods: The dogs were divided into three groups: chronic or recurrent otitis externa (CO), otitis media (OM) and H (healthy). The dogs with otitis underwent a CT scan of the head, measurement of the plasma CRP concentration and evaluation of a 0-3 Otitis Index Score 3 (OTIS3 score).

Results: No dog (0%) in group H had an increased CRP value, compared to 20% in the CO group (one of five dogs) and 23% in the OM group (3 of 13 dogs). Plasma CRP concentrations show a statistically significant positive relationship with the OTIS3 score (p = 0.04).

Conclusion and clinical relevance: Plasma CRP concentration is not reliable as a discriminatory tool in cases of otitis, although there is a trend for elevation in cases with more severe disease. However, a larger study may provide a statistically more reliable correlation between the severity of OM and CRP concentrations.