Medscape is available in 5 Language Editions – Choose your Edition here.


Acanthamoeba Treatment & Management

  • Author: Nancy F Crum-Cianflone, MD, MPH; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
Updated: Nov 30, 2015

Medical Care

Medical therapy for Acanthamoeba infection is not well established. Early diagnosis and treatment are paramount for improving outcome. Listed below are treatments that have been reported in the literature.


Successful treatment of keratitis consists of early diagnosis and aggressive surgical and medical therapies.[10, 11]

Medical treatment consists of topical antimicrobial agents, which can achieve high concentrations at the site of the infection.

Because the cyst form may be highly resistant to therapy, a combination of agents is generally used.

Many authorities recommend a combination of chlorohexidine (0.02%) and polyhexamethylen biguanide (PHMB, 0.02%) for treating both the trophozoites and cysts.[11] Using one of these agents in combination with propamidine (Brolene) or hexamidine (Desmodine) has been described but the latter agents are not available in the US.

These topical antimicrobials are administered every hour immediately after corneal debridement or for the first several days of therapy. These agents are then continued hourly during waking hours for 3 days (at least 9 times/day is recommended) depending on clinical response. The frequency is then reduced to every 3 hours. Two weeks may be required before a response is observed, and the total duration of therapy is a minimum of 3-4 weeks. Some advocate treating for 6-12 months. When therapy is discontinued, close observation is warranted to rule out recurrent disease.

No clear consensus exists about use of steroids. Most authorities recommend that steroid use is probably best avoided. Patients receiving steroids should continue antiamebic therapy for several weeks after the steroids are stopped. Rabinovitch and coworkers (1991) showed that steroid use was significantly greater among patients in whom medical therapy failed than in those whose medical therapy was successful.[12] A more recent study by Park et al (1997) revealed no difference in response to medical therapy in patients who used topical steroids compared with those who did not. However, in this study, patients treated with topical steroids required longer duration of medical therapy (38.5 wk vs 20 wk).[13] One of the potential risks of steroids is suprainfection with bacteria.

Granulomatous amebic encephalitis

Treatment is not standardized and is limited. Most use a combination of therapies for the treatment of GAE, which should be urgently administered. Antibiotic sensitivity testing should be performed and may help guide therapy.

Early therapy with a multidrug regimen is the best approach. A combination of pentamidine, an azole (fluconazole or itraconazole), a sulfadiazine, and flucytosine can be considered.

In vitro and in vivo data suggest that the following medications have activity against Acanthamoeba:

  • Ketoconazole, miconazole, itraconazole, fluconazole, voriconazole
  • Pentamidine
  • Amphotericin B (to a lesser extent)
  • Paromomycin
  • Polymyxin
  • Trimethoprim-sulfamethoxazole
  • Sulfadiazine
  • Flucytosine
  • Clotrimazole
  • Rifampin

Other potential regimens have included several combinations of the above agents.

Two immunocompetent children survived with treatment that consisted of ketoconazole, rifampin, and trimethoprim-sulfamethoxazole. A recent case reported discussed the use of this combination, but the patient ultimately relapsed and died of progressive leukemia.[14]

Other potential regimens include (1) fluconazole and sulfadiazine or (2) pentamidine, amphotericin, flucytosine, rifampin, itraconazole, and chlorhexidine.

Disseminated disease

A case that involved only the skin was treated with intravenous pentamidine, topical chlorhexidine gluconate, and 2% ketoconazole cream, followed by oral itraconazole.


Surgical Care

Keratitis: The abnormal epithelium is débrided. Penetrating keratoplasty/corneal transplantation may be necessary in cases that do not respond to medical therapy.[15]



See the list below:

  • Keratitis
    • Infectious diseases specialist
    • Ophthalmologist
  • Granulomatous amebic encephalitis and disseminated disease
    • Infectious diseases specialist
    • Neurologist
Contributor Information and Disclosures

Nancy F Crum-Cianflone, MD, MPH Consulting Staff, Department of Internal Medicine, Division of Infectious Diseases, Naval Medical Center at San Diego

Nancy F Crum-Cianflone, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Richard B Brown, MD, FACP Chief, Division of Infectious Diseases, Baystate Medical Center; Professor, Department of Internal Medicine, Tufts University School of Medicine

Richard B Brown, MD, FACP is a member of the following medical societies: Alpha Omega Alpha, American College of Chest Physicians, American College of Physicians, American Medical Association, American Society for Microbiology, Infectious Diseases Society of America, Massachusetts Medical Society

Disclosure: Nothing to disclose.

Chief Editor

Pranatharthi Haran Chandrasekar, MBBS, MD Professor, Chief of Infectious Disease, Program Director of Infectious Disease Fellowship, Department of Internal Medicine, Wayne State University School of Medicine

Pranatharthi Haran Chandrasekar, MBBS, MD is a member of the following medical societies: American College of Physicians, American Society for Microbiology, International Immunocompromised Host Society, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Additional Contributors

David Hall Shepp, MD Program Director, Fellowship in Infectious Diseases, Department of Medicine, North Shore University Hospital; Associate Professor, New York University School of Medicine

David Hall Shepp, MD is a member of the following medical societies: Infectious Diseases Society of America

Disclosure: Received salary from Gilead Sciences for management position.


The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous coauthor William B. Harley, MD, to the development and writing of this article.

  1. Lorenzo-Morales J, Khan NA, Walochnik J. An update on Acanthamoeba keratitis: diagnosis, pathogenesis and treatment. Parasite. 2015. 22:10. [Medline].

  2. Kurbanyan K, Hoesl LM, Schrems WA, Hamrah P. Corneal nerve alterations in acute Acanthamoeba and fungal keratitis: an in vivo confocal microscopy study. Eye (Lond). 2011 Nov 11. [Medline].

  3. Nazar M, Haghighi A, Niyyati M, Eftekhar M, Tahvildar-Biderouni F, Taghipour N, et al. Genotyping of Acanthamoeba isolated from water in recreational areas of Tehran, Iran. J Water Health. 2011 Sep. 9(3):603-8. [Medline].

  4. Acanthamoeba keratitis multiple states, 2005-2007. MMWR Morb Mortal Wkly Rep. 2007 Jun 1. 56(21):532-4. [Medline].

  5. Lorenzo-Morales J, Martín-Navarro CM, López-Arencibia A, Arnalich-Montiel F, Piñero JE, Valladares B. Acanthamoeba keratitis: an emerging disease gathering importance worldwide?. Trends Parasitol. 2013 Apr. 29(4):181-7. [Medline].

  6. Schaumberg DA, Snow KK, Dana MR. The epidemic of Acanthamoeba keratitis: where do we stand?. Cornea. 1998 Jan. 17(1):3-10. [Medline].

  7. Wilhelmus KR, Jones DB, Matoba AY, et al. Bilateral acanthamoeba keratitis. Am J Ophthalmol. 2008 Feb. 145(2):193-197. [Medline].

  8. Molyneux PM, Kilvington S, Wakefield MJ, Prydal JI, Bannister NP. Autofluorescence Signatures of Seven Pathogens: Preliminary in Vitro Investigations of a Potential Diagnostic for Acanthamoeba Keratitis. Cornea. 2015 Dec. 34 (12):1588-92. [Medline].

  9. Parmar DN, Awwad ST, Petroll WM, et al. Tandem scanning confocal corneal microscopy in the diagnosis of suspected acanthamoeba keratitis. Ophthalmology. 2006 Apr. 113(4):538-47. [Medline].

  10. Oldenburg CE, Acharya NR, Tu EY, Zegans ME, Mannis MJ, Gaynor BD, et al. Practice patterns and opinions in the treatment of acanthamoeba keratitis. Cornea. 2011 Dec. 30(12):1363-8. [Medline]. [Full Text].

  11. Clarke B, Sinha A, Parmar DN, Sykakis E. Advances in the diagnosis and treatment of acanthamoeba keratitis. J Ophthalmol. 2012. 2012:484892. [Medline]. [Full Text].

  12. Rabinovitch T, Weissman SS, Ostler HB, et al. Acanthamoeba keratitis: clinical signs and analysis of outcome. Rev Infect Dis. 1991 Mar-Apr. 13 Suppl 5:S427. [Medline].

  13. Park DH, Palay DA, Daya SM, et al. The role of topical corticosteroids in the management of Acanthamoeba keratitis. Cornea. 1997 May. 16(3):277-83. [Medline].

  14. Gupta D, Panda GS, Bakhshi S. Successful treatment of acanthamoeba meningoencephalitis during induction therapy of childhood acute lymphoblastic leukemia. Pediatr Blood Cancer. 2008 Jun. 50(6):1292-3. [Medline].

  15. Sarnicola E, Sarnicola C, Sabatino F, Tosi GM, Perri P, Sarnicola V. Early Deep Anterior Lamellar Keratoplasty (DALK) for Acanthamoeba Keratitis Poorly Responsive to Medical Treatment. Cornea. 2015 Nov 9. [Medline].

  16. Acanthamoeba keratitis in soft-contact-lens wearers. MMWR Morb Mortal Wkly Rep. 1987 Jul 3. 36(25):397-8, 403-4. [Medline].

  17. Cunha BA. Antibiotic Essentials. 5th ed. Royal Oak, Mich: Physician's Press; 2006.

  18. De Jonckheere JF. Ecology of Acanthamoeba. Rev Infect Dis. 1991 Mar-Apr. 13 Suppl 5:S385-7. [Medline].

  19. Hammersmith KM. Diagnosis and management of Acanthamoeba keratitis. Curr Opin Ophthalmol. 2006 Aug. 17(4):327-31. [Medline].

  20. Kaji Y, Hu B, Kawana K, et al. Swimming with soft contact lenses: danger of acanthamoeba keratitis. Lancet Infect Dis. 2005 Jun. 5(6):392. [Medline].

  21. Lindquiest td. Treatment of Acanthamoeba keratitis. Cornea. 1998. 17:11-16.

  22. Marciano-Cabral F, Cabral G. Acanthamoeba spp. as agents of disease in humans. Clin Microbiol Rev. 2003 Apr. 16(2):273-307. [Medline].

  23. Martinez AJ. Infection of the central nervous system due to Acanthamoeba. Rev Infect Dis. 1991 Mar-Apr. 13 Suppl 5:S399-402. [Medline].

  24. Mathers WD, Nelson SE, Lane JL, et al. Confirmation of confocal microscopy diagnosis of Acanthamoeba keratitis using polymerase chain reaction analysis. Arch Ophthalmol. 2000 Feb. 118(2):178-83. [Medline].

  25. Migueles S, Kumar P. Primary cutaneous acanthamoeba infection in a patient with AIDS. Clin Infect Dis. 1998 Dec. 27(6):1547-8. [Medline].

  26. Nachega JB, Rombaux P, Weynand B, et al. Successful treatment of Acanthamoeba rhinosinusitis in a patient with AIDS. AIDS Patient Care STDS. 2005 Oct. 19(10):621-5. [Medline].

  27. Oliva S, Jantz M, Tiernan R, et al. Successful treatment of widely disseminated acanthamoebiasis. South Med J. 1999 Jan. 92(1):55-7. [Medline].

  28. Paltiel M, Powell E, Lynch J, et al. Disseminated cutaneous acanthamebiasis: a case report and review of the literature. Cutis. 2004 Apr. 73(4):241-8. [Medline].

  29. Schaumberg DA, Snow KK, Dana MR. The epidemic of Acanthamoeba keratitis: where do we stand?. Cornea. 1998 Jan. 17(1):3-10. [Medline].

  30. Singh U. Free-Living Amebas. Mandell, Douglas, and Bennetts Principles and Practices of Infectious Diseases.

  31. Singhal T, Bajpai A, Kalra V, Kabra SK, Samantaray JC, Satpathy G, et al. Successful treatment of Acanthamoeba meningitis with combination oral antimicrobials. Pediatr Infect Dis J. 2001 Jun. 20(6):623-7. [Medline].

  32. Sison JP, Kemper CA, Loveless M, et al. Disseminated acanthamoeba infection in patients with AIDS: case reports and review. Clin Infect Dis. 1995 May. 20(5):1207-16. [Medline].

  33. Slater CA, Sickel JZ, Visvesvara GS, et al. Brief report: successful treatment of disseminated acanthamoeba infection in an immunocompromised patient. N Engl J Med. 1994 Jul 14. 331(2):85-7. [Medline].

  34. Stapleton F, Seal DV, Dart J. Possible environmental sources of Acanthamoeba species that cause keratitis in contact lens wearers. Rev Infect Dis. 1991 Mar-Apr. 13 Suppl 5:S392. [Medline].

  35. Sun X, Zhang Y, Li R, et al. Acanthamoeba keratitis: clinical characteristics and management. Ophthalmology. 2006 Mar. 113(3):412-6. [Medline].

  36. Thebpatiphat N, Hammersmith KM, Rocha FN, et al. Acanthamoeba keratitis: a parasite on the rise. Cornea. 2007 Jul. 26(6):701-6. [Medline].

All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.