The sting itself is only moderately painful, with little associated tissue damage, but approximately 30 minutes later, the patient develops a complex of systemic symptoms including severe back and abdominal pain, limb or joint pain, nausea and vomiting, profuse sweating and agitation. They may also experience numbness or paraesthesia. Hypertension and tachycardia are frequently seen, and are thought to be related to catecholamine release. Supraventricular tachycardia and transient dilated cardiomyopathy have been reported following Irukandji stings, and it has been suggested that serial echocardiography be performed to monitor the progress of severely affected patients. Analgesia is usually required, and may need to be given intravenously when pain is severe.
First aid consists of analgesia and reassurance.
The role of vinegar to inactivate undischarged nematocysts remains uncertain, with initial work proving inconclusive. No definitive treatment is currently available for the Irukandji syndrome. The Australian Venom Research Unit is currently involved in research to develop an antivenom to treat Irukandji envenomation. They are distributed throughout the world's warmer waters, and are often found in groups. Stings cause moderate pain for up to 2 hours, with associated swelling and redness.