EXPERT ANALYSIS AT ACDASM 2017
SYDNEY (FRONTLINE MEDICAL NEWS) – Think twice before prescribing oral steroids for patients who have urticarial dermatitis, diarrhea, and cough, especially if they have lived in or recently traveled to tropical areas, Ian McCrossin, MD, said at the annual meeting of the Australasian College of Dermatologists.
Strongyloides stercoralis, or threadworm, infection can flare dramatically when patients take oral steroids. “You get thousands of worms, and they punch their way through the bowel wall and take the bowel organisms with them; that’s when you get septicaemia,” Dr. McCrossin, a dermatologist from Liverpool Hospital, Sydney, said in an interview.
Strongyloidiasis is relatively rare in developed countries, but it is endemic in parts of Southeast Asia, Central America, and Africa. The most common way of becoming infected with Strongyloides is by walking barefoot in soil that is contaminated with Strongyloides larvae. The parasite, which spreads through sewage-contaminated soil and invades the human host through their feet, has an autoinfection cycle. As a result, individuals can remain infected for decades.
Dr. McCrossin cited an Australian study that found a strongyloides infection was present in 11.6% of 309 Vietnam veterans living in South Australia.
Risk factors for Strongyloides hyperinfection include compromised immunity, human T-cell lymphotropic virus type 1, alcohol use disorder, malnutrition, and oral steroid use. Mortality rates from the resulting sepsis are as high as 87%, Dr. McCrossin said.
IgG ELISA is a reliable test for established strongyloidiasis, but is less effective for recent infection, hyperinfection, and in patients who are immunosuppressed. Eosinophilia has a poor predictive value. Light microscopy of stool samples may require evaluation of multiple stool samples unless the patient had hyperinfection.
Treatment generally consists of ivermectin, 200 mcg/kg orally for 1-2 days. Follow-up stool exams should be performed 2-4 weeks after treatment to confirm clearance of infection. In those patients with hyperinfections, ivermectin 200 mcg/kg orally is given daily until stool and/or sputum exams are negative for 2 weeks.
Dr. McCrossin declared no conflicts of interest.
