PATIENT HISTORY
A 24-year-old White man presents to a clinic with an erythematous, serpiginous, slightly raised rash on his left foot that has been present for 1 week (Figure 1). The lesion is mildly pruritic but not painful. The patient has used Neosporin on the area with no response. Two months ago, the patient visited Jamaica, and he is concerned it might be an infection. He is not diabetic and denies any injuries to the area or any similar symptoms in the past. The remainder of his physical examination is noncontributory.
Multiple-Choice Question
Which of the following is the most appropriate treatment option for this patient?
A. Topical triamcinolone acetonide
B. Topical tacrolimus
C. Oral prednisone
D. Oral ivermectin
E. Oral diphenhydramine
Answer
D. Oral ivermectin
DISCUSSION
This patient has a serpiginous eruption suggestive of hookworm-related cutaneous larva migrans (CLM) that was likely acquired during his trip to Jamaica. Hookworm-related CLM is most frequently caused by Ancylostoma braziliense and Ancylostoma caninum, which are cat and dog hookworm larvae, respectively, that can penetrate the skin (Chris & Keystone, 2016). The hookworm larvae are generally confined to the epidermis, as they are unable to penetrate the basement membrane. Therefore, humans are incidental hosts in which the larvae are unable to complete their life cycle. It is common in developing nations in the Caribbean, Central and South America, and Southeast Asia. Travelers often contract CLM after walking barefoot or sitting on contaminated beaches or soil in tropical countries. As a result, the lesions most commonly occur on the feet, buttocks, and legs (Heukelbach & Feldmeier, 2008).
The diagnosis of CLM is based on clinical symptoms and recent travel history. Biopsies are typically not performed because the larvae are usually found 1-2 centimeters away from the visible border (Prickett & Ferringer, 2015). Patients have one to three lesions on average, and the incubation period is usually less than 1 week after exposure. However, larvae have been reported to be dormant for as long as 7 months. A characteristic symptom of CLM is creeping eruption also termed "creeping dermatitis," which is a serpiginous or linear cutaneous tract that migrates in an irregular pattern. The eruptions are approximately 3 millimeters wide, slightly raised, and erythematous (Figure 1) as well as pruritic and sometimes painful. Lesions may also be vesiculobullous or edematous or present as folliculitis or diffuse urticarial papules (Heukelbach & Feldmeier, 2008; Hochedez & Caumes, 2008; Prickett & Ferringer, 2015).
Creeping eruptions may also be present in other parasitic cutaneous diseases including larva currens, dracunculiasis, scabies, and loiasis. Larva currens is caused by Strongyloides stercoralis and is similar in presentation. Strongyloides stercoralis is found in the southern United States, Southeast Asia, Central Africa, and South America. It can be distinguished from CLM by the speed of progression in the epidermis. Whereas CLM progresses only a few millimeters to a centimeter a day, larva currens is much more rapid and can migrate up to 10 centimeters per hour (Elston, Czarnik, Brockett, & Keeling, 2003; Monsel & Caumes, 2008). In addition, rashes caused by larva currens only persist for a few hours and characteristically occur on the trunk and thighs and near the anus (Heukelbach & Feldmeier, 2008).
CLM is usually self-limiting and resolves spontaneously without treatment within 2-8 weeks. However, patients often prefer active intervention, especially because lesions can be severely pruritic and can affect patients' quality of life (Prickett & Ferringer, 2015). In addition, treatment can decrease the risk of superimposed bacterial infection secondary to excoriation (Kincaid, Klowak, Klowak, & Boggild, 2015). One dose of oral ivermectin (200 [mu]g/kg) and 3 days of oral albendazole (400-800 mg) are both effective treatments. Patients with numerous lesions or folliculitis may require additional doses of anthelmintic agents (Monsel & Caumes, 2008). If those medications are unavailable or contraindicated, topical 10% albendazole ointment applied twice a day for at least 10 days is a viable substitute (Hochedez & Caumes, 2008). Topical 10%-15% thiabendazole ointment applied three times daily for a minimum of 15 days is also utilized to treat CLM, but it requires strict patient compliance (Caumes, 2000).
REFERENCES