eMedicine Specialties > Dermatology > Parasitic Infections

Strongyloidiasis: Differential Diagnoses & Workup

Author: Robert A Schwartz, MD, MPH, Professor and Head, Dermatology, Professor of Pathology, Pediatrics, Medicine, and Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School
Coauthor(s): Mordechai M Tarlow, MD, Physician, Department of Medicine, Section of Dermatology, Kimball Medical Center
Contributor Information and Disclosures

Updated: May 29, 2009

Differential Diagnoses

Contact Dermatitis, Allergic
Erythema Annulare Centrifugum
Scabies

Other Problems to Be Considered

Human hookworm infection with Ancylostoma duodenale or Necator americanus
Zoonotic infection with S myopotami, S procyonis, Ancylostoma braziliensis, or Ancylostoma caninum

 Strongyloides colitis is an easily curable yet potentially lethal mimic of ulcerative colitis.14  One should have a high index of suspicion and should be aware of GI similarities with ulcerative colitis. Strongyloides colitis should be included in the differential diagnosis of ulcerative colitis.

Workup

Laboratory Studies

  • Routine blood testing
    • The CBC count usually reveals a normal WBC count in acute and chronic strongyloidiasis. The WBC count may be elevated in severe strongyloidiasis.
    • Eosinophilia of 10-40% is common during acute infection; it may be as high as 75-80%. Eosinophilia also occurs in chronic infection, although it is intermittent and may not be found at all during severe infection.
    • The total serum immunoglobulin E (IgE) level is usually elevated.
    • Severe infection may be associated with anemia, thrombocytopenia, and a prolonged prothrombin time (PT) because of decreased levels of clotting factors.
    • Obtain blood cultures in all patients in whom Strongyloides infection is suspected because enteric pathogens often cause co-infection.
  • Stool examination for ova and parasites15
    • Definitive diagnosis depends on the microscopic demonstration of S stercoralis larvae in the feces.
    • The larvae resemble those of hookworms, but they can be distinguished by their short buccal cavity.
    • Ova are almost never observed during strongyloidiasis unless severe diarrhea occurs.
    • Several fresh stool specimens may need to be examined before a positive result is found. At least 3 separate examinations on different days are recommended to achieve a sensitivity of approximately 70-80%.
    • Stool samples may be concentrated with zinc sulfate prior to examination to enhance the recovery of larvae. A modified agar plate method is superior to other techniques used for stool examination.
    • Duodenal fluid can be aspirated or examined by using the Entero-Test, or the string capsule method. This test offers a higher likelihood of larval recovery than simple stool examination.
  • Serologic analysis
    • Although serologic analysis is the most sensitive test for strongyloidiasis (sensitivity, 84-92%), it is not specific, and cross-reactions with other nematode infections are possible. Therefore, microscopic analysis is also necessary for diagnosis.
    • Common serologic tests used in diagnosing strongyloidiasis include the enzyme immunoassay (EIA) and the enzyme-linked immunosorbent assay (ELISA). However, a stool and serosurvey for S stercoralis conducted in a community in the Peruvian Amazon region found the ELISA test had a negative predictive value of 98% and is an excellent screening test for strongyloidiasis.7
    • Gelatin particle agglutination test (GPAT) and ELISA results were evaluated in endemic regions of Thailand.16 In this work, the GPAT was judged to be more practical for screening for strongyloidiasis than the conventional ELISA.
  • Often, establishing a diagnosis and confirming a cure of strongyloidiasis is difficult. Strongyloides -specific antibody levels may be used for serological follow-up for strongyloidiasis.17 They may indicate reversion to negative serostatus after successful ivermectin therapy, which is frequent.

Imaging Studies

  • Systemic infection is associated with findings that may be observed with imaging studies.
    • Alveolar or interstitial infiltrates or pulmonary effusion may be visible on chest radiographs.
    • Severe infection may be associated with loss of the mucosal pattern, rigidity, and tubular narrowing, as depicted on abdominal radiographs.

Procedures

  • In acute or chronic infection, skin biopsy is usually neither necessary nor sufficient because parasites are rarely visualized. When they are, speciation is difficult.
  • In severe infection, skin biopsy may be useful because filariform larvae are often observed. Obtain specimens from the purpuric eruptions because these areas contain the largest amount of larvae.
  • Intestinal colonoscopy may reveal multiple findings, including normal mucosa, moderate inflammation, or severe duodenitis and colitis, particularly in immunosuppressed patients. Histopathologic examination identified larvae in 71.4% of those immunosuppressed by duodenal biopsy.18 Thus, in addition to stool analysis, endoscopic observation and biopsies are very important.19
  • Lumbar puncture and cerebrospinal fluid (CSF) evaluation are indicated when CNS involvement is suspected.
  • In severe infections, sputum examination or bronchoalveolar lavage is appropriate for the identification of larvae.

Histologic Findings

Skin biopsy is often helpful in severe infection. Larvae can be observed in all levels of the dermis and occasionally in the subcutis. Other findings include edema, extravasated RBCs, and some lymphocytes in the superficial dermis. Larvae range from 9-15 µm in size. They contain a triradiate digestive tract.

Biopsy of the duodenum or jejunum reveals larvae in the lamina propria, where they produce edema, a cellular infiltrate, villous atrophy, or even fibrosis in prolonged infection.

More on Strongyloidiasis

Overview: Strongyloidiasis
Differential Diagnoses & Workup: Strongyloidiasis
Treatment & Medication: Strongyloidiasis
Follow-up: Strongyloidiasis
References
Further Reading
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References

  1. Robson D, Welch E, Beeching NJ, Gill GV. Consequences of captivity: health effects of far East imprisonment in World War II. QJM. Feb 2009;102(2):87-96. [Medline].

  2. Chandrasekar PH, Bharadwaj RA, Polenakovik H, Polenakovik S. Strongyloidiasis. eMedicine from WebMD [serial online]. April 3, 2009;Available at http://emedicine.medscape.com/article/229312-overview.

  3. Milder JE, Walzer PD, Kilgore G, Rutherford I, Klein M. Clinical features of Strongyloides stercoralis infection in an endemic area of the United States. Gastroenterology. Jun 1981;80(6):1481-8. [Medline].

  4. Pelletier LL Jr. Chronic strongyloidiasis in World War II Far East ex-prisoners of war. Am J Trop Med Hyg. Jan 1984;33(1):55-61. [Medline].

  5. Pelletier LL Jr, Gabre-Kidan T. Chronic strongyloidiasis in Vietnam veterans. Am J Med. Jan 1985;78(1):139-40. [Medline].

  6. Pattison DA, Speare R. Strongyloidiasis in personnel of the Regional Assistance Mission to Solomon Islands (RAMSI). Med J Aust. Aug 18 2008;189(4):203-6. [Medline].

  7. Yori PP, Kosek M, Gilman RH, et al. Seroepidemiology of strongyloidiasis in the Peruvian Amazon. Am J Trop Med Hyg. Jan 2006;74(1):97-102. [Medline].

  8. Johnston FH, Morris PS, Speare R, et al. Strongyloidiasis: a review of the evidence for Australian practitioners. Aust J Rural Health. Aug 2005;13(4):247-54. [Medline].

  9. Fardet L, Genereau T, Poirot JL, Guidet B, Kettaneh A, Cabane J. Severe strongyloidiasis in corticosteroid-treated patients: case series and literature review. J Infect. Jan 2007;54(1):18-27. [Medline].

  10. Guyomard JL, Chevrier S, Bertholom JL, Guigen C, Charlin JF. [Finding of Strongyloides stercoralis infection, 25 years after leaving the endemic area, upon corticotherapy for ocular trauma]. J Fr Ophtalmol. Feb 2007;30(2):e4. [Medline].

  11. Salluh JI, Bozza FA, Pinto TS, Toscano L, Weller PF, Soares M. Cutaneous periumbilical purpura in disseminated strongyloidiasis in cancer patients: a pathognomonic feature of potentially lethal disease?. Braz J Infect Dis. Oct 2005;9(5):419-24. [Medline].

  12. Goncalves AL, Machado GA, Goncalves-Pires MR, Ferreira-Junior A, Silva DA, Costa-Cruz JM. Evaluation of strongyloidiasis in kennel dogs and keepers by parasitological and serological assays. Vet Parasitol. Jun 20 2007;147(1-2):132-9. [Medline].

  13. Meamar AR, Rezaian M, Mohraz M, Hadighi R, Kia EB. Strongyloides stercoralis hyper-infection syndrome in HIV+/AIDS patients in Iran. Parasitol Res. Aug 2007;101(3):663-5. [Medline].

  14. Qu Z, Kundu UR, Abadeer RA, Wanger A. Strongyloides colitis is a lethal mimic of ulcerative colitis: the key morphologic differential diagnosis. Hum Pathol. Apr 2009;40(4):572-7. [Medline].

  15. Sato Y, Kobayashi J, Toma H, Shiroma Y. Efficacy of stool examination for detection of Strongyloides infection. Am J Trop Med Hyg. Sep 1995;53(3):248-50. [Medline].

  16. Sithithaworn J, Sithithaworn P, Janrungsopa T, Suvatanadecha K, Ando K, Haswell-Elkins MR. Comparative assessment of the gelatin particle agglutination test and an enzyme-linked immunosorbent assay for diagnosis of strongyloidiasis. J Clin Microbiol. Jul 2005;43(7):3278-82. [Medline].

  17. Page WA, Dempsey K, McCarthy JS. Utility of serological follow-up of chronic strongyloidiasis after anthelminthic chemotherapy. Trans R Soc Trop Med Hyg. Nov 2006;100(11):1056-62. [Medline].

  18. Kishimoto K, Hokama A, Hirata T, et al. Endoscopic and histopathological study on the duodenum of Strongyloides stercoralis hyperinfection. World J Gastroenterol. Mar 21 2008;14(11):1768-73. [Medline].

  19. Mittal S, Sagi SV, Hawari R. Strongyloidiasis: endoscopic diagnosis. Clin Gastroenterol Hepatol. Feb 2009;7(2):e8. [Medline].

  20. Pacanowski J, Santos MD, Roux A, et al. Subcutaneous ivermectin as a safe salvage therapy in Strongyloides stercoralis hyperinfection syndrome: a case report. Am J Trop Med Hyg. Jul 2005;73(1):122-4. [Medline].

  21. Robson D, Beeching NJ, Gill GV. Strongyloides hyperinfection syndrome in British veterans. Ann Trop Med Parasitol. Mar 2009;103(2):145-8. [Medline].

  22. Fasih N, Irfan S, Sheikh U, Beg MS. A fatal case of gram negative bacterial sepsis associated with disseminated strongyloidiasis in an immunocompromised patient. J Pak Med Assoc. Feb 2008;58(2):91-2. [Medline].

  23. Nuesch R, Zimmerli L, Stockli R, Gyr N, Christoph Hatz FR. Imported strongyloidosis: a longitudinal analysis of 31 cases. J Travel Med. Mar-Apr 2005;12(2):80-4. [Medline].

  24. Amer M, Attia M, Ramadan AS, Matout K. Larva currens and systemic disease. Int J Dermatol. Jul-Aug 1984;23(6):402-3. [Medline].

  25. Markell EK, John DT, Krotoski WA. Markell and Voge's Medical Parasitology. 8th ed. Philadelphia, Pa: WB Saunders; 1999:287-93.

  26. Ouimet MJ, Munoz M, Narasiah L, Rambure V, Correa JA. [Current pathologies among asylum seekers in Montreal: prevalence and associated risk factors]. Can J Public Health. Nov-Dec 2008;99(6):499-504. [Medline].

  27. Roeckel IE, Lyons ET. Cutaneous larva migrans, an occupational disease. Ann Clin Lab Sci. Sep-Oct 1977;7(5):405-10. [Medline].

  28. Smith JD, Goette DK, Odom RB. Larva currens. Cutaneous strongyloidiasis. Arch Dermatol. Aug 1976;112(8):1161-3. [Medline].

  29. Stone OJ, Newell GB, Mullins JF. Cutaneous strongyloidiasis: larva currens. Arch Dermatol. Nov 1972;106(5):734-6. [Medline].

  30. von Kuster LC, Genta RM. Cutaneous manifestations of strongyloidiasis. Arch Dermatol. Dec 1988;124(12):1826-30. [Medline].

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Keywords

strongyloidiasis, cutaneous strongyloidiasis, cutaneous larva migrans, larva currens, racing larva, creeping eruption, creeping infection, threadworm infection, disseminated strongyloidiasis, Strongyloides stercoralis, S stercoralis

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Contributor Information and Disclosures

Author

Robert A Schwartz, MD, MPH, Professor and Head, Dermatology, Professor of Pathology, Pediatrics, Medicine, and Preventive Medicine and Community Health, UMDNJ-New Jersey Medical School
Robert A Schwartz, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American College of Physicians, and Sigma Xi
Disclosure: Nothing to disclose.

Coauthor(s)

Mordechai M Tarlow, MD, Physician, Department of Medicine, Section of Dermatology, Kimball Medical Center
Mordechai M Tarlow, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, American Society for MOHS Surgery, American Society of Cosmetic Dermatology and Aesthetic Surgery, and Sigma Xi
Disclosure: Nothing to disclose.

Medical Editor

James J Nordlund, MD, Professor Emeritus, Department of Dermatology, University of Cincinnati College of Medicine
James J Nordlund, MD is a member of the following medical societies: American Academy of Dermatology, Sigma Xi, and Society for Investigative Dermatology
Disclosure: Nothing to disclose.

Pharmacy Editor

Michael J Wells, MD, Associate Professor, Department of Dermatology, Texas Tech University Health Sciences Center
Michael J Wells, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, and Texas Medical Association
Disclosure: Nothing to disclose.

Managing Editor

Rosalie Elenitsas, MD, Herman Beerman Associate Professor of Dermatology, University of Pennsylvania School of Medicine; Director, Penn Cutaneous Pathology Services, Department of Dermatology, University of Pennsylvania Health System
Rosalie Elenitsas, MD is a member of the following medical societies: American Academy of Dermatology and American Society of Dermatopathology
Disclosure: Nothing to disclose.

CME Editor

Glen H Crawford, MD, Assistant Clinical Professor, Department of Dermatology, University of Pennsylvania School of Medicine; Chief, Division of Dermatology, The Pennsylvania Hospital
Glen H Crawford, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, Phi Beta Kappa, and Society of USAF Flight Surgeons
Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

 
 
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