University College Hospital

Cutaneous Larva MigransHospital for Tropical Diseases, Infection Division

If you need a large print, audio or translated copy of this document, please contact us on 020 3456 7891. We will try our best to meet your needs.

First published: October 2008Last review date: March 2014Next review date: March 2016Leafl et code: UCLH/MB/ID/HTD/CLM/1© University College London Hospitals NHS Foundation Trust

Created by Medical Illustration RNTNEH 020 3456 5103 Unique Code: 29299

Contact detailsTelephone: 020 3456 7891Fax: 020 7388 7645

Address: The Hospital for Tropical Diseases 2nd Floor Mortimer Market Capper Street Off Tottenham Court Road London WC1E 6JB

Website: www.thehtd.org www.uclh.nhs.uk

Written by: Dr Robin Bailey Diana Phillips

Will I have problems after taking Ivermectin?Several million people worldwide have been treated with Ivermectin and few have had any problems. Occasionally, people have reported dizziness, drowsiness, nausea, bloating, diarrhoea, headache, muscle aches and allergic reactions. If you experience drowsiness you should avoid driving, operating machinery, and limit your alcohol intake.

Will it do me any harm? No. In dogs the larvae migrate to the gut but they cannot move beyond the skin in humans and do not live for very long.

They typically migrate around the skin in the area that they fi rst invaded until they die. This process usually lasts for a week or two, but in some cases can take months.

Will I infect anyone else?No. CLM cannot be passed from person to person.

How can I treat it?As mentioned above, CLM does not cause any harm and the larvae eventually die without treatment. The rash then heals spontaneously.However the larvae can live for several months and many people fi nd the itchy rash irritating and cosmetically unpleasant and so opt to have it treated promptly.

We can treat your CLM with a tablet called Ivermectin (given once only). The dosage is weight-based (200mcg/kg) and we will weigh you in the clinic. You should also inform us if you are pregnant or breastfeeding. There are alternatives to taking Ivermectin.

What is CLM?Cutaneous larva migrans, or CLM, is a parasitic skin infection. CLM is caused by hookworm larvae that usually infect cats, dogs and other animals.

The most common type of hookworm that causes CLM is called Ancylostoma braziliense which usually infects dogs. When animals defecate on soil or sand the hookworm eggs pass out with the faeces onto the soil and eventually hatch into larvae.

Humans become infected when these larvae penetrate the skin. This usually happens to people who have been sunbathing on contaminated sandy beaches or walking over moist soil. CLM is commonly found in those who have visited tourist beaches in the Caribbean and South East Asia.

At the site of penetration red eruptions occur.The larvae may then begin creeping, causing two to three millimetres wide, worm-like tracks. The tracks are slightly raised, red or pink in colour and may itch intensely. Once creeping has started the tracks can advance from a few millimetres to a few centimetres daily.If many larvae are involved a series of loops and tracks may form.