Got the Travel Bug? A Review of Common Infections, Infestations, Bites, and Stings Among Returning Travelers

Matthew P. Vasievich; Jose Dario Martinez Villarreal; Kenneth J. Tomecki


Am J Clin Dermatol. 2016;17(5):451-462. 

In This Article

Marine Envenomation

Marine envenomation is a common complaint in travelers to North America, Australia, and Oceania, as well as travelers to the Middle East and the Mediterranean region of Europe, and accounts for 5–10 % of travel-related complaints from these regions.[3] Symptoms from most stings are acute and require immediate medical attention; however, it is important to continue care in the returned traveler after initial treatment at the time of injury.


Stingrays are large flat fish that live and feed on the bottom of fresh and salt waters in tropical and subtropical climes worldwide, including several species in the USA. Most stingray stings occur in victims unintentionally startling or stepping on the fish. The stinger is a barbed apparatus located on the dorsal aspect of the tail, which whips forward and embeds in the skin. The stinger has an associated gland that coats it in venom and mucus. The sting itself is intensely painful, and the stinger often breaks off, leaving fragments lodged in the victim. Pain and edema peak within 30–90 min and can last 1–2 days. Nausea, vomiting, weakness, and balance disturbances may also occur.[55] Treatment consists of obtaining hemostasis of the wound and immersing the wound in hot water (110–114 °F or 43–46 °C) to ameliorate the pain; infiltration with local anesthetic may be helpful. The wound should be explored for stinger debris, cleaned, debrided, packed, and left to heal by secondary intent. The patient should receive tetanus toxoid prophylaxis and possibly a prophylactic antibiotic to prevent soft tissue infection.[56,57]

Spiny-finned Fish

Lionfish, stonefish, and weever fish are spiny-finned fish that are commonly implicated in marine stings, not only in travelers/swimmers but also (particularly lionfish) in individuals with saltwater aquariums.[58] Stonefish live in tropical waters and on reefs, particularly off the coasts of Australia and India. They feed near the ocean floor and are reddish to gray-brown colored as camouflage with their surroundings. Stings often occur from the victim stepping unknowingly on the fish. Weever fish are sandy-brown fish, 6–12 inches in length, that inhabit shallow waters around Europe; they are bottom dwellers, with stings occurring when a victim steps on them. Lionfish are striped fish indigenous to the reefs of the Indian and western Pacific Oceans, though their numbers have also been increasing in Caribbean waters.[59] Lionfish are not aggressive to swimmers, and stings usually occur in fishermen or aquarium owners.[58] A spiny fish sting is similar to a stingray sting. Pain peaks within the first 30–90 min and generally resolves within 1–2 days. Nausea, vomiting, and weakness can occur, likely as a result of the pain from the sting. Treatment is similar to a stingray attack as described above.[60] Of note, anti-venom is available for stonefish stings, often at clinics near waters the fish inhabit. Dosing of the anti-venom should correlate with the number of puncture wounds observed: intramuscular 2000 U for 1–2 punctures, 4000 U for 3–4 punctures, and 6000 U for ≥5 punctures. There is a risk of anaphylaxis to the anti-venom, and a serum-sickness reaction can occur within 3 weeks of anti-venom administration. The anti-venom is not FDA approved.[61]

Box Jellyfish

The box jellyfish (Chironex fleckeri or commonly, the 'sea wasp') lives in the Indian and Pacific Oceans off Australia and south-east Asia. The animal measures approximately 12 inches in diameter, and its tentacles are several meters in length, each with thousands of nematocysts, which are hollow needle-like structures that deploy from a spring-like apparatus and inject venom into the victim. The box jellyfish is one of the most venomous animals in the world. Human death can occur within seconds to minutes of contact with the toxin. The mechanism of action of the jellyfish toxin is unknown but is thought to circulate in the blood of the victim after a sting and create pores in the plasma membrane of cells, causing a potassium efflux and cardiovascular collapse and/or respiratory failure.[62,63] Box jellyfish stings produce flagellate edematous purpura that may evolve to bullae and necrosis. Fever, nausea, vomiting, and headache may occur. Initial treatment is stabilization of hemodynamics and respiratory status. Application of 5 % acetic acid (white vinegar) helps to decontaminate the victim from undischarged nematocysts. Freshwater and physical rubbing can exacerbate the sting by triggering undischarged nematocysts. After decontamination, box jellyfish anti-venom should be administered, coupled with cold packs topically and analgesia as needed. Topical or systemic corticosteroids and antihistamines may also be helpful.[64,65]

Portuguese Man-of-war

The Portuguese Man-of-War (Physalia physalis) is found worldwide. The organism is actually a colony of smaller polyp-like organisms that floats on the surface of the ocean using a gas bladder filled with nitrogen and carbon monoxide gases. It has approximately 40 tentacles, some 30 m in length, to ensnare its prey. The Man-of-War floats passively on the ocean, propelled only by the wind and waves; as such, it occasionally can be found washed up on beaches. Man-of-War stings are characterized by flagellate erythema from nematocyst discharge and associated severe pain that can last up to several hours. Nausea, malaise, headache, delirium, and gait ataxia can occur. Hypotension and respiratory failure are uncommon but may occur in severe stings. Treatment for Man-of-War stings is similar to that for box jellyfish stings, but no anti-venom is available.[56,65]

Sea Bather's Eruption

Sea bather's eruption is a pruritic dermatitis caused by the larvae of the thimble jellyfish (Linuche unguiculata), which are present throughout the world, though commonly found in the waters off Florida and in the Caribbean. The dermatitis develops when larvae, which measure only 1–2 mm in diameter, become trapped beneath the swimwear of the victim and cause pruritic erythematous edematous papules and wheals resembling urticaria (Fig. 11). The papules and wheals occur within a day of exposure to the larvae and can persist for up to 2 weeks. Severe reactions can cause headache, fever, chills, nausea, and vomiting. Treatment is primarily supportive with acetic acid decontamination followed by symptomatic treatment with topical corticosteroids and oral antihistamines. If symptoms are severe, systemic steroids may be effective.[66,67]

Figure 11.

Sea bather's eruption