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Acanthamoeba Clinical Presentation

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


Keratitis is usually associated with a history of improper cleaning of contact lenses, using homemade sodium chloride solution to clean the lenses, and swimming in fresh water or a swimming pool, especially while contact lenses are worn. Rarely, this infection develops after radial keratotomy. The incubation period is a few days. Keratitis typically begins with a foreign-body sensation followed by pain, tearing, photophobia, blepharospasm, and blurred vision. Patients may have periods of symptom remission with a waxing and waning course. Bilateral involvement has been described in up to 11% of cases.[7]

Granulomatous amebic encephalitis (GAE) is a subacute diffuse meningoencephalitis, usually with an insidious onset. The incubation period is unknown but is probably weeks to months. The duration of illness until death ranges from 7-120 days (average, 39 d). Patients with GAE may have concurrent sinus, lung, or skin disease. Most patients present with focal neurologic deficits; other symptoms are as follows:

  • Mental status changes (86%)
  • Seizures (66%)
  • Hemiparesis (53%)
  • Fever (53%)
  • Headache (53%)
  • Meningismus (40%)
  • Visual disturbances (26%)
  • Ataxia (20%)
  • Nausea and vomiting
  • Hallucinations
  • Personality changes
  • Photophobia
  • Sleep disturbances

Skin disease may predate the onset of CNS manifestations by weeks to months and may include ulcers, nodules, or subcutaneous abscesses. Disseminated disease without CNS involvement may manifest as skin lesions, sinusitis, pneumonitis, or a combination. Other unusual manifestations of Acanthamoeba infections have included osteomyelitis, adrenalitis, and vasculitis.



See the list below:

  • Keratitis
    • Conjunctivitis or conjunctival hyperemia
    • Corneal ulceration
    • Lid edema
    • A characteristic corneal ring stromal infiltrate (dendritiform epitheliopathy)
    • Anterior uveitis of fluctuating severity
    • Increased intraocular pressures
    • Hypopyon
    • Cataract formation
  • Granulomatous amebic encephalitis
    • Altered mental status
    • Ataxia
    • Fever
    • Hemiparesis
    • Cranial nerve deficits
    • Meningismus, Babinski sign, and Kernig sign
    • Diplopia, photophobia
    • Coma
    • Concurrent skin lesions, sinus tenderness, or pulmonary rales
  • Disseminated disease without GAE may manifest as skin lesions that are typically hard erythematous nodules or skin ulcers. Other presentations of disseminated disease include pneumonitis and sinusitis.


See the list below:

  • Keratitis
    • Wearing contact lenses
    • Using homemade sodium chloride solutions to clean contact lenses
    • Wearing contacts while swimming
    • Cleaning contact lenses less frequently than recommended by the manufacturer
  • Granulomatous amebic encephalitis and disseminated disease: Acanthamoeba is ubiquitous; most persons are exposed to this organism. Although rare cases have been described in immunocompetent adults and children, the main risk factors for the development of disease include immunocompromising conditions and factors associated with immunosuppression, such as the following:
    • AIDS
    • Liver disease
    • Transplantation
    • Diabetes mellitus
    • Steroid use
    • Systemic lupus erythematosus
    • Cancer that requires chemotherapy
    • Malnutrition
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].

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