A majority of Kudoa spp. infects the somatic muscle of fish establishing cysts. Previously, elevated humoral responses were detected in BALB/c mice immunised with Kudoa sp. pseudocyst extracts and in BALB/c mice orally inoculated with Kudoa sp. pseudocysts, as well as the presence of anti-Kudoa sp. antibodies in human sera by enzyme-linked immunosorbent assay. The objective of this work was to test Kudoa sp. pseudocyst extracts by the skin prick test. Fifteen patients with gastroallergic and/or allergic symptoms related to fish ingestion were examined. Kudoa sp. pseudocyst extracts were administered (1 mg/ml) on the volar forearm skin. Four of the 15 selected patients were positive to Kudoa sp. extracts. The saline solution negative control did not induce any reaction.