What is Cutaneous Larva Migrans (Creeping Eruption)?
Cutaneous larva migrans (CLM), otherwise known as creeping eruption, is a disease caused by several types of hookworms. It’s commonly spread by animal droppings that release eggs in the soil. These eggs hatch into larvae, which can infect humans by coming into direct contact with their skin. CLM is different from other skin infections caused by parasites, including one called larva currens, which involves worms moving quickly under the skin. Other skin conditions involving worms, like loiasis, scabies, or worms that can penetrate skin, are not classified as CLM.
CLM is mainly seen in warmer climates, such as southeast United States, Latin America, Southeast Asia, and Africa. The symptoms include a moving, worm-shaped rash, often itchy, which can appear anywhere on exposed skin, but most commonly appears on the feet. The disease usually resolves on its own because the worms can’t make an enzyme to get through the skin and move into the gut to reproduce. If treatment is required, certain creams or tablets can be used. Sometimes, complications can occur from other bacteria infecting the skin, or from inappropriate therapy.
What Causes Cutaneous Larva Migrans (Creeping Eruption)?
Cutaneous larva migrans (CLM) is a condition where larvae, specifically very small worms, move around just under the skin. This typically comes from certain types of hookworms found in animals, such as Ancylostoma braziliense, Ancylostoma caninum, and Uncinaria stenocephala. However, there are certain types of human hookworms, like Ancylostoma duodenale and Necator americanus, which can also lead to this condition.
Risk Factors and Frequency for Cutaneous Larva Migrans (Creeping Eruption)
The disease-causing organisms are mostly found in tropical areas such as the Southeastern United States, Latin America, the Caribbean, Southeast Asia, and Africa. The disease is most common during the wet seasons. Most affected tourists traveling to these hotspots tend to be younger.
Signs and Symptoms of Cutaneous Larva Migrans (Creeping Eruption)
If a person has recently traveled to areas where certain infections are common and has a habit of walking barefoot, they may be at risk of certain skin infections. One of the first signs is usually a small, red bump that eventually turns into a winding, itchy rash. This rash can grow slowly, often less than 1 to 2 cm per day. Depending on what type of organism has infected the person, the symptoms may show up differently.
- For example, if the person is infected by A. braziliense, symptoms can show up within an hour.
- If the infection is caused by U. stenocephala, it can take a few days for red, bump-like lesions to appear.
In some cases, the disease can cause blisters or pus-filled bumps. However, it’s important to note that these symptoms are not common.
Testing for Cutaneous Larva Migrans (Creeping Eruption)
The diagnosis of this condition is often made based on a patient’s recent history of travel to areas where the disease is common, coupled with a distinctive, itchy rash that gradually expands over time. This rash is different from those caused by other types of infection as it grows at a slower pace, typically at a rate of just millimeters up to 2 cm per day.
Even though doctors could use blood tests to help with this diagnosis, these tests usually aren’t required. Moreover, they might not be reliable as less than 40% of patients with this disease show an increase in a type of white blood cell called eosinophils. However, this increase isn’t exclusive to this condition; it can occur in many other diseases too.
Some doctors have used a type of non-invasive technology that provides high-resolution images of the skin layers, known as optical coherence tomography. Although this tool isn’t commonly used.
Sometimes, a skin biopsy may be performed where a small piece of skin is removed for examination. This procedure might show the presence of the worm-like parasites associated with the disease within a circular canal. However, this test isn’t perfect, only some biopsies yield valuable information. Also, these tests may pick up secondary changes and infiltrate, which can help aid in fleshing out a diagnosis, but are not necessary to confirm it.
Treatment Options for Cutaneous Larva Migrans (Creeping Eruption)
The disease can naturally resolve over time, but if the infection is local, a thiabendazole solution or ointment may be applied topically. For best results, the cream should be applied about 2 to 3 times a day over a duration of 5 to 10 days. Several small studies have shown that symptoms such as itching can improve as early as two days after starting treatment, and a high cure rate of up to 98% can be achieved within ten days. Topical therapy’s main advantage is its side effects are minimal due to the lack of systemic absorption. However, it’s not ideal for multiple lesions due to the need for regular application.
Cryotherapy, which involves freezing skin, was once used to treat local disease. But it’s been proven largely ineffective and hence should be avoided.
For treating multiple lesions or severe infestation, the recommended treatments are albendazole and ivermectin. Albendazole should be taken orally at a daily dose of 400 mg for 3 to 5 days. This treatment has shown to be highly effective with nearly 100% cure rates. Some studies suggest that extending albendazole treatment to 7 days can reduce the chances of the disease returning. Ivermectin is also effective and only requires a single oral dose of 12 mg. Cure rates with Ivermectin are usually as high as 100%.
Mebendazole is another treatment option, but it’s not as effective due to poor absorption in the body, therefore, it’s not recommended as a first choice. Other treatments proven ineffective include topical steroids, oral steroids, and antibiotics. Oral steroids may help reduce itching but have too many side effects to be considered useful.
In addition to medications, preventative measures such as banning dogs from beaches could also be beneficial in reducing the spread of infection. However, towels do not consistently protect against transmission. On the other hand, wearing protective footwear can significantly reduce the risk of infection.
What else can Cutaneous Larva Migrans (Creeping Eruption) be?
While the slow-spreading rash and symptoms can usually point doctors towards a diagnosis, other conditions can sometimes cause confusion. Certain skin infections such as scabies, loiasis, myiasis, schistosomiasis, tinea corporis, and contact dermatitis might share some similar traits. However, these can typically be distinguished by the absence of a pattern that looks like a winding path or ‘serpentine migration.’
The condition that most closely resembles this is the moving skin lesion caused by a parasitic worm, Strongyloides stercoralis, known as larva currens. This condition is different due to its speed of progression, with the infection moving at rates of several centimeters per hour. The pattern of the infection is also random and it’s frequently found on the skin around the anus, thighs, or torso.
Fascioliasis, a disease caused by a large parasite called Fasciola gigantica, is another condition that doctors might consider.
Non-infectious conditions that might cause similar symptoms include jellyfish stings, lichenoid eruptions, and phytophotodermatitis, but these do not spread and migrate like the primary infection. Ingrown hair that appears to ‘creep’ or slowly spread is another possible condition, but it’s pretty rare.
What to expect with Cutaneous Larva Migrans (Creeping Eruption)
This illness often resolves itself without treatment. However, it can persist for months, during which the itchiness can become severe and disrupt sleep. Whether treated topically or systemically (throughout the body), the probability of completely curing the disease approaches 100%. While the disease can recur, it can be easily prevented or cured with systemic treatment.
Possible Complications When Diagnosed with Cutaneous Larva Migrans (Creeping Eruption)
Complications can arise from the secondary infection, usually caused by bacteria such as Staphylococcus aureus and Streptococcal species. In up to 8% of cases, there’s a type of skin infection called secondary impetiginization. If the infection continues for a long time, it can lead to a kidney condition known as post-streptococcal glomerulonephritis.
Although it is generally agreed that larvae cannot penetrate the skin’s basement membrane, there have been rare instances of visceral disease, where the infection spreads to the internal organs. These larvae have been found in sputum, the viscera of a human host (internal organs), and skeletal muscles.
On rare occasions, the body’s response to the infection has resulted in a skin condition called erythema multiforme.
Common Complications:
- Secondary infection, often from Staphylococcus aureus and Streptococcal species
- Secondary impetiginization
- Post-streptococcal glomerulonephritis
- Visceral disease
- Larvae found in sputum, visceras, and skeletal muscles
- Erythema multiforme
