Myiasis Treatment & Management

Author: Eleni Grammatikopoulou, MD; Chief Editor: Rick Kulkarni, MD more...

Updated: Apr 21, 2011

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Prehospital Care
Emergency Department Care
Consultations
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References

Prehospital Care

Prehospital care is not required.

First-line treatment - Surgical removal with local anesthesia

Surgical removal with local anesthesia is usually the preferred approach. The skin lesion is locally anesthetized with lidocaine and excised surgically followed by primary wound closure. Alternatively, lidocaine can be injected forcibly into the base of the lesion in an attempt to create enough fluid pressure to extrude the larvae out of the punctum.^[13]Another surgical approach would be to perform a 4- to 5-mm punch excision of the overlying punctum and surrounding skin to gain better access to and visibility of the larva. The larva can then be removed carefully using toothed forceps (experience of B. B. Wilson).

The larva should not be forcibly removed through the central punctum because its tapered shape with rows of spines and hooks prevents simple extrusion.

Furthermore, care should be taken to avoid lacerating the larva because retained larval parts may precipitate foreign body reaction. After the removal of the larvae, antiseptic dressings are indicated, as well as antibiotics if secondary infection is present.

Second-line treatment - Occlusion/suffocation approaches

These treatments include petroleum jelly, liquid paraffin, beeswax or heavy oil, or lard or bacon strips placed over the central punctum and have been used to coax the larva to emerge spontaneously head-first over the course of several hours, at which time, tweezers (or forceps) aid in the capture. A suffocation technique is shown in the image below.

Suffocation technique. Placement of a beef strip over the central punctum to coax larvae to exit. Image courtesy of Kenneth E Greer.

These approaches take advantage of the larva's oxygen requirements, encouraging it to exit on its own. However, the covering should not be restrictive (eg, nail polish) because this may asphyxiate the larvae without causing them to migrate out of the skin.

Third-line treatment - Systemic/topical ivermectin

An alternative treatment for all types of myiasis is oral ivermectin (200 mcg/kg) ivermectin or topical ivermectin (1% solution), proven especially helpful with oral and orbital myiasis.

Wound myiasis

Wound myiasis requires debridement with irrigation to eliminate the larvae from the wound or surgical removal. Application of chloroform, chloroform in light vegetable oil, or ether, with removal of the larvae under local anesthesia, has been advocated for wound myiasis.^{[1, 13]}

Surgical removal is not required unless requested by the patient, as the larvae are naturally sloughed within 5-7 weeks.

Consultations

Depending on the location of the larval infestation, dermatologists (wound and furuncular myiasis), ophthalmologists (ophthalmomyiasis), or otorhinolaryngologists (oral, facial, nasal myiasis) may need to be consulted.

Proceed to Medication

Contributor Information and Disclosures

Author

Eleni Grammatikopoulou, MD Visiting Physician, University of Virginia School of Medicine

Disclosure: Nothing to disclose.

Coauthor(s)

Barbara B Wilson, MD Edward P Cawley Associate Professor, Department of Dermatology, University of Virginia School of Medicine

Barbara B Wilson, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Medical Society of Virginia, and Sigma Xi

Disclosure: Nothing to disclose.

Specialty Editor Board

Robert L Norris, MD Professor, Department of Surgery; Chief, Division of Emergency Medicine, Stanford University Medical Center

Robert L Norris, MD is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, California Medical Association, International Society of Toxinology, Society for Academic Emergency Medicine, and Wilderness Medical Society

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Senior Pharmacy Editor, eMedicine

Disclosure: eMedicine Salary Employment

John D Halamka, MD, MS Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Rick Kulkarni, MD

Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: WebMD Salary Employment

References

Bolognia JL, Jorizzo JL, Rapini R. Cutaneous myiasis. In: Dermatology. Vol 1. 2^nd ed. Mosby Elsevier; 2008:1300-01.
Burns T, Breathnach S, Cox N, Griffiths C. Diseases caused by arthropods and other noxious animals. In: Rook's Textbook of Dermatology. Vol 2. 7^th ed. Malden, MA: Blackwell Publishing; 2004:33.8 - 11.
Auerbach PS. Arthropod envenomation and parasitism. In: Wilderness Medicine. 5^th ed. Philadelphia, PA: Mosby Elsevier; 2007:969-974.
Mandell GL, Bennett JE, Dolin R. Infectious diseases and their etiologic agents. In: Principles and Practice of Infectious Diseases. Vol 2. 5^th ed. Philadelphia, PA: Churchill Livingstone; 2000:2976-2979.
Cestari TF, Pessato S, Ramos-e-Silva M. Tungiasis and myiasis. Clin Dermatol. Mar-Apr 2007;25(2):158-64. [Medline].
Masoodi M, Hosseini K. External ophthalmomyiasis caused by sheepbotfly (Oestrus Ovis) larva: a report of 8 cases. Arch Iran Med. 2004;7:136-139.
Aydin E, Uysal S, Akkuzu B, et al. Nasal myiasis by fruit fly larvae: a case report. Eur Arch Otorhinolaryngol. Dec 2006;263(12):1142-3. [Medline].
Sharma H, Dayal D, Agrawal SP. Nasal myiasis: review of 10 years experience. J Laryngol Otol. May 1989;103(5):489-91. [Medline].
Terterov S, Taghva A, MacDougall M, Giannotta S. Posttraumatic human cerebral myiasis. World Neurosurg. May 2010;73(5):557-9. [Medline].
Garvin KW, Singh V. Case report: cutaneous myiasis caused by Dermatobia hominis, the human botfly. Travel Med Infect Dis. May 2007;5(3):199-201. [Medline].
Ofordeme KG, Papa L, Brennan DF. Botfly myiasis: a case report. CJEM. Sep 2007;9(5):380-2. [Medline].
Quintanilla-Cedillo MR, Leon-Urena H, Contreras-Ruiz J, Arenas R. The value of Doppler ultrasound in diagnosis in 25 cases of furunculoid myiasis. Int J Dermatol. Jan 2005;44(1):34-7. [Medline].
Lebwohl MG, Heymann WR, Berth-Jones J, Coulson I. Myiasis. In: Treatment of Skin Diseases. Comprehensive Therapeutic Strategies. 2^nd ed. Elesevier-Mosby; 2006:420-421.
Osorio J, Moncada L, Molano A, et al. Role of ivermectin in the treatment of severe orbital myiasis due to Cochliomyia hominivorax. Clin Infect Dis. Sep 15 2006;43(6):e57-9. [Medline].
Costa DC, Pierre-Filho Pde T, Medina FM, Mota RG, Carrera CR. Use of oral ivermectin in a patient with destructive rhino-orbital myiasis. Eye. Sep 2005;19(9):1018-20. [Medline].
Clyti E, Nacher M, Merrien L, et al. Myiasis owing to Dermatobia hominis in a HIV-infected subject: Treatment by topical ivermectin. Int J Dermatol. Jan 2007;46(1):52-4. [Medline].

Mature larva of the Dermatobia hominis fly; rows of hooks apparent on its tapered body. Image courtesy of Kenneth E Greer.

Boil-like lesion on toe of a patient with botfly myiasis; the central punctum is apparent. Image courtesy of Kenneth E Greer.

Boil-like lesions on a patient with botfly myiasis; the central punctum is apparent. Image courtesy of Kenneth E Greer.