Larva Currens in a Patient Scheduled for Renal Transplant
We present a case of larva currens in a patient scheduled for renal transplant. Larva currens is an eruption caused by Strongyloides stercoralis, characterized most often by a pathognomonic, migratory, rapidly extending, serpiginous, urticarial eruption. Infected patients who are immunocompromised are at risk for disseminated and often fatal infection. In disseminated disease, diffuse petechiae and purpura may be present, and periumbilical ecchymoses may resemble thumbprints. The dermatologist may be in a unique position to diagnose this condition and institute therapy. Although found endemically in the United States, the increasingly international nature of medical practice and transplantation medicine causes an increase in the number of patients who may present for evaluation.
Pulmonary symptoms in acute infection can occur and include wheezing, coughing, and shortness of breath.1 Larval migration through the lungs also can lead to transient pulmonary infiltrates. Some patients have presented with asthma.11 Patients with chronic disease may have gastrointestinal tract and pulmonary symptoms, though chronic infection tends to be indolent and patients may be asymptomatic.
Diagnosis can be difficult, as results from stool samples often are negative and multiple samples may be required. Results of biopsies performed on larva currens specimens usually do not reveal larvae, though biopsy results of the petechial and purpuric eruptions of disseminated disease will reveal larvae. Serologic testing with enzyme-linked immunosorbent assay has a sensitivity of approximately 90%.12,13
Traditionally, thiabendazole has been used to treat this infection, though in approximately 30% of cases, the parasite is not eradicated from the feces. Ivermectin has been found to be more effective for treating uncomplicated chronic disease.14
In most cases of disseminated disease, patients were receiving corticosteroids or other immunosuppressive drugs or had an underlying illness, such as malignancy or AIDS.1,2,15,16 Our patient was scheduled to undergo a renal transplant and fatal disseminated strongyloidiasis has been reported in patients undergoing renal transplant.2,16 Morgan et al2 reviewed 29 cases of strongyloidiasis complicating renal transplants; 15 patients died.
Infection in the immunocompromised patient can be complicated by the fact that invasive larvae can transport gram-negative bacilli from the intestine to sites of migration, such as the pulmonary and central nervous systems.5 Gram-negative sepsis, meningitis, or pneumonia can result. Diagnosis can be difficult because eosinophilia often is absent in immunocompromised patients with disseminated disease.5
Although common in tropical and subtropical countries, other geographic regions of endemic Strongyloides are recognized. The climate and soil of the southeastern United States favor the survival of the organism,5 and the parasite was reported in 3% (N=561) of a group of rural Kentucky schoolchildren17; similar findings were reported in another study conducted in Kentucky.18Strongyloides also was the most commonly detected parasite in a review of stool samples examined at the University of Kentucky Medical Center.19 Ex–prisoners of war who served in Southeast Asia during World War II also constitute an at-risk group in the United States.20-22
It is imperative to rule out the presence of this parasite prior to transplant in patients with a geographic history predisposing them to infection, a history of eosinophilia, or symptoms of chronic strongyloidiasis.1 Many transplantation centers routinely screen for this parasite as part of the pretransplant evaluation. Although uncommon in acute infections, cutaneous involvement often is present in chronic strongyloidiasis.1 It also is important to follow patients already treated for larva currens closely posttransplant, as therapeutic failures occur.
