Cutaneous larva migrans is a parasitic infection caused by a hookworm. This hookworm can be found in the digestive tracts of dogs, cats, and other animals. Classically, people become infected with this worm when they are barefoot at either the beach or the lake. After becoming infected, pink to red snake like lines appear on the affected area. These areas can become intensely itchy. This infection is often called a creeping eruption because people will notice that the line where the parasite is will slowly extend day to day.
The most at risk people include beachcombers, children in sandpits, gardeners, plumbers, and hunters. On contact with human skin, the larvae can penetrate through hair follicles, cracks or even intact skin to infect the human host. Between a few days and a few months after the initial infection, the larvae migrate beneath the skin. In an animal host the larvae are able to penetrate the deeper layers of the skin (the dermis) and infect the blood and lymphatic system. Once in the intestine they mature sexually to create more eggs that are then excreted to start the cycle again. However, in a human host, the larvae are unable to penetrate the basement membrane to invade the dermis so the disease remains confined to the outer layers of the skin.
A non-specific eruption occurs at the site of penetration of the hookworm larvae. There may be a tingling or prickling sensation within 30 minutes of the larvae penetrating. The larvae can then either lie dormant for weeks or months or immediately begin creeping activity that create 2-3mm wide, snakelike tracks stretching 3-4cm from the penetration site. These are slightly raised, flesh-colored or pink and cause intense itching. Tracks advance a few millimeters to a few centimeters daily and if many larvae are involved a disorganized series of loops and tortuous tracks may form.
Sites most commonly affected by cutaneous larva migrans are the feet, spaces between the toes, hands, knees and buttocks.
Cutaneous larva migrans is self-limiting. In other words, it will resolve eventually without treatment. Humans are an accidental and “dead-end” host so the hookworm larvae eventually die. The natural duration of the disease varies considerably depending on the species of larvae involved. In most cases, lesions will resolve without treatment within 4-8 weeks.
However, effective treatment is available to shorten the course of the disease.
- Anthelmintics (pills) Itching is considerably reduced within 24-48 hours of starting antihelmintic treatment and within 1 week most lesions/tracts resolved.
- Antihistamines and topical corticosteroids may also be used with anthelminthics to provide symptomatic relief of itch.
- Secondary bacterial infection may require treatment with appropriate antibiotics.
If you are having any difficulties with your skin, please call our office and make an appointment with one of our excellent dermatology providers for a skin check. We would be happy to be a trusted part of your health care.
Bentonville: 701 NW McNelly Rd., Bentonville, AR 72712 (479-268-3555)
Fayetteville: 1444 E Stearns St., Fayetteville, AR 72703 (479-718-7546)
Harrison: 520 N Pine St., Harrison, AR 72601 (870-204-5279)
Ryan Crowder, MPAS, PA-C