Cutaneous larva migrans: an itchy red line after the beach

Cutaneous larva migrans is caused by hookworms (Ancylostoma) that normally live in dogs and cats. Their eggs pass in the animals' feces and, in sand or soil, become larvae that can get through the skin when someone walks barefoot or lies on the sand. According to the Merck Manual, it occurs worldwide but is most common in tropical areas.

In people, the larva cannot complete its life cycle: it stays in the skin, moves under it and eventually dies. That is why it is not serious, even though the itch can be intense. It does not spread from person to person.

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• Where and when you had recent contact with sand or soil (barefoot, lying on the beach, playing in the sand)
• Where the line is, since when and how far it has moved
• Good light and close-up photos of the rash
• Whether you are pregnant or breastfeeding, since it changes which treatment is safe
• Your medicines and allergies
• The name of your pharmacy, or one near your hotel if you are visiting

Cutaneous larva migrans is handled in a doctor visit, the same price for every age, with no membership. You pay by card when you request the visit, and you get a full refund if the clinic can’t see you. The pharmacy charges separately. See prices.

It starts where the larva entered, usually the feet, legs, buttocks or back. The CDC describes tracks that can move up to a few centimeters a day.

• A thin, red, wavy line under the skin
• Very intense itching
• The line moves or changes place over the days
• Sometimes blisters form along the line

Without treatment it goes away on its own, but that can take weeks to months, with a lot of itching. That is why it is usually treated. According to the Merck Manual and the AAP, treatment is an antiparasitic medicine by mouth, such as albendazole or ivermectin, or in some cases a cream. The doctor chooses the right one for you, if appropriate.

Do not scratch or try to dig the larva out: it does not work and can infect the skin. If the area gets very red, hot, swollen or has pus, it may be a skin infection.

The larvae enter through skin that touches sand or soil contaminated with dog or cat feces:

• Wear sandals or shoes on the sand and on soil where dogs or cats roam.
• Lie on a towel or chair, not directly on the sand.

Cutaneous larva migrans is not an emergency. For your safety, get in-person care or call 911 if you notice:

• Fever with redness that is spreading, hot and painful
• Red streaks running up the leg from the rash
• Trouble breathing or facial swelling after taking a medicine