An unusual marine envenomation following a rope contact: a report on nine cases of dermatitis caused by Pennaria disticha.

We would like to present the clinical course of nine patients who had an acute, painful dermatitis following contact with a rope used as a swimming area liner in the sea. The macroscopic and microscopic analysis of the fouling on the rope retrospectively, revealed Pennaria disticha as the causative organism. To our knowledge, there is no previous report on P. disticha envenomation in medical literature. P. disticha is a benthic hydrozoa belonging to Cnidaria phylum. Cnidaria are well known for their envenomation with their venomous organelle, "cnidocyst". The contact with cnidaria can result in a wide range of cytotoxic or anaphylactic reactions. While there is a large body of data in the literature from studies at molecular and cellular levels, there is limited data about the in vivo effects of cnidaria toxins. We think the clinical aspects of the dermatologic reactions caused by P. disticha and the diagnostic work-up to reveal the contamination on this unusual medium would be of interest to the readers.