Jellyfish envenomation acquired in the Andaman Sea, Malaysia, in a returning traveller

Background Jellyfish stings are common tropical marine injuries, but clinicians in non-tropical settings may be unfamiliar with their presentation and early management.Case presentation A 60-year-old woman was stung while swimming at Rhu Beach, Langkawi Island, Malaysia. She developed immediate intense burning pain, vomiting, transient generalized muscle spasms, linear erythematous skin lesions, and progressive swelling of the right foot. After a long-haul flight to Poland, persistent unilateral limb oedema and elevated D-dimer (1036 ng/mL) raised concern for thrombosis; Doppler ultrasonography was negative. Symptomatic treatment and prophylactic anticoagulation were followed by complete recovery.Conclusions Imported jellyfish envenomation can present as a diagnostic dilemma in returning travellers, particularly when local inflammatory swelling overlaps with post-flight thromboembolic concerns. Recognition of characteristic linear lesions and evidence-based first-aid advice are important for travel medicine practice.