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Year : 2009  |  Volume : 11  |  Issue : 1  |  Page : 40-42

Otoacriasis of the ear: A case report and literature review

Assistant Professor and Consultant, Department of Otorhinolaryngology, King Abdulaziz Hospital, Riyadh, Saudi Arabia

Date of Web Publication7-Jan-2020

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DOI: 10.4103/1319-8491.275324

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The author reports a very rare case of mite otoacriasis with review of the world literature. The patient presented with a history of intractable bilateral ear itching for more than two years. The condition defied diagnosis until mite infestation was demonstrated.
The diagnosis was established by microscopic ear examination and laboratory examination of the causative arthropods. Mite infestation of the external auditory canal is a very rare condition, which is scarcely reported in the literature . The condition may pose difficulty in diagnosis because live mite are not clearly recognized by the human eye.

Keywords: otoacriasis, otitis externa, Acaria Histiostomatidate.

How to cite this article:
Al-Arfaj A. Otoacriasis of the ear: A case report and literature review. Saudi J Otorhinolaryngol Head Neck Surg 2009;11:40-2

How to cite this URL:
Al-Arfaj A. Otoacriasis of the ear: A case report and literature review. Saudi J Otorhinolaryngol Head Neck Surg [serial online] 2009 [cited 2022 Dec 4];11:40-2. Available from: https://www.sjohns.org/text.asp?2009/11/1/40/275324

  Introduction Top

Accidental entry of animate foreign body and arthropods is a common etiology of aural foreign bodies presenting to the accident and emergency department. Most of the affected patients seek immediate medical advice especially if the insect of a relatively large size like cockroaches, ants, mosquitoes and flies. However, if the size of the infesting arthropod is very tiny ( like a mite ), the case may not be easy to detect and may even pass undiagnosed or misdiagnosed for a long time. This gives the insects a chance to multiply and increase in number before being diagnosed and treated. The aim of this study was to present a patient who complained for 30 months from intractable ear itching caused by mite infestation of the external auditory canal. A review of the literature revealed that the condition is a very rare disorder.

  Case Report: Top

The patient was a 31 year-old Saudi patient studying chemical engineering in the USA. He was living in the USA from early 2001 to December 2002. The only time he travelled during this period was in the summer of 2001, when he made a trip to Saudi Arabia. Three months after his return to the USA he developed bilateral ear itching. This was accompanied by attacks of earache ,intermittent scanty thick yellow otorrhoea and aural fullness. Despite his persistent symptoms, he did not seek medical attention while in the USA. On his return to Saudi Arabia at the end of 2002 he consulted many otolaryngologists for his ear condition. He received varied medical treatments with no improvement. He received many courses of topical and systemic antibiotics as a treatment for his ‘otitis externa’. Aural syringing was performed more than five times in order to remove ‘wax’ from his ears. The itching used to improve for few days after syringing to recur again. He was also treated with antifungal medication on the assumption that his condition was otomycosis but without any success. On February 2004, the patient was seen by the author at the ENT clinic at King Abdulaziz University Hospital, Riyadh, Saudi Arabia. By this time, it has been 3 months since the onset of symptoms. On otoscopic examination, the skin of the external auditory canal was found to be thickened, ,with white sheets of sloughed cells and thick discharge. Microscopic examination at higher magnification was done using a video otoscope. Both external auditory canals showed thickening and scaling of the skin with thick sheets of cell debris. There were numerous moving arthropods ( looking like sheep in a raising ranch) which appeared more in the medial sides of the canals. The tympanic membranes were intact with a slight degree of hyperkeratosis and moving organisms on the surface [Figure 1]. The ears were syringed with normal saline and the returning fluid was sent to the laboratory for examination. The recovered organism was identified as mites. Samples of the mites were then slide-mounted for microscopic examination and electron microscopy scanning at King Khalid University Hospital in Riyadh, Saudi Arabia (Department of Pathology) and also at Auburn University , Auburn, USA (Department of Entomology and Plants Pathology). The details of the technique used to identify the mites have been explained in another publication [1]. It showed that the mites belonged to a single astigmatid species, representing most development stages i.e. eggs, larvae, homeomorphic nymphs and adults. They were tentatively identified as members of the family Histomatidae ( Anoetidae). They represent un-described species closely related to members of the genu Loxanoetus. A scanning electron micrograph of the anthropode is shown in [Figure 2]. The patient was reviewed after one week. He reported remarkable improvement in the itching. Examination showed mite eradication from the right ear and presence of few mites ( numbered 5-10 ) in the left ear canal with good improvement in the appearance of the skin. Another ear syringing with 70% ethanol was done and he was then treated daily with ear drops Eurax® ( crotamin ) lotion ( Novartis. Horsham, U.K.) for one week, at the end of which symptoms cleared and an otoscopic examination demonstrated complete clearance of the mites. The patient was followed up for 12 months with no signs of recurrence.
Figure 1: A number of mites crawling about in the walls of the external auditory canal and on the tympanic membrane of the right ear ( original magnification x 30)

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Figure 2: Scanning electron micrograph of the mite ( original magnification x 115)

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  Discussion Top

Otoacriasis is a term applied to ear infestation by Acarina anthropods ( characterized by fusing of the cephalothorax and abdomen ). The Acarina family is one order of the Arachnida class ( characterized by having four pairs of legs). The Acarina anthropods include two major groups, the ticks and the mites. Ticks are microscopic in size and possess toothed hypostome. Ticks are obligatory blood feeders on vertebrate hosts. They parasitize reptiles, birds and mammals. No ticks feed on plant juices or prey on other anthropods. In addition to otoacriasis , ticks may cause anaemia ( due to blood loss ), dermatosis ( due to inflammation from bites), and paralysis ( due to released of neurotoxins). Ticks may also transmit viruses, bacteria, rickettesia or protozoa causing various diseases e.g. Rocky Mountain fever ( transmitted by tick Dermacentor andersoni). On the other hand, mites are microscopic in size ( usually less than 1 mm ), and can be difficult to see and identify without the aid of a microscope or at least a hand lens. Mites have unarmed hypostomes. There are more than 200 families of mites and many thousands of species. Most mites are free living and feed on plant juices or prey upon other anthropods. Some mites have evolved to become important ectoparasitic pests of animals. Some other species have even become endoparasites by invading the ears, noses, and other tissues of animals. The mites of medical importance include Srcoptiformes ( scabies mites), Dermatophagoides ( house dust mite ), Demdicidae ( follicle mites), and Dermannyssidae ( bird and rodent mites). The life cycle of mites and ticks consist of eggs, larva, one or more nymphal and adults stages. The entire life cycle can take as little as eight days to as long as four weeks, depending on the species of mite, and the temperature and humidity.

Otoacriasis is a term applied to infestation of the external ear canals by either ticks or mites ( Acarina anthropods). In the literature, there are some studies which have reported a large number of patients with tick otoacriasis ( 2-10). The largest series of human otoacriasis recorded in the literature was reported by Dilrukshi et al [9]. They reported intra-aural ticks in 870 patients. This represented 15.2% of 5714 patients who reported with ear-related complaints to the ear, nose and throat ward at Sri Lanka’s Hospital over a two-year period. Indudharan et al [8] ,reported 40 patients with tick otoacriasis , presenting 21% of 193 cases with animate foreign bodies seen over a 7-year period in a Malaysian Hospital. Mite otoacriasis on the other hand , have been reported only as a rare case report [11],[12],[13],[14]. A review of the English literature revealed only four papers reporting a total of five patients with mite otoacriasis. Van de Heyning and Thienpont ( 1988 ), reported external otitis in a woman caused by Otodectes cybcotis mite of cats and dogs [11]. Rossiter [1997], described two cases of external canal infestation with Dermanyssus gallinae, the red poultry mite [12]. Cho et al ( 1999) , reported a case of storage mite, Sancassania berlesei,, infestation in the external canal of a 46-year male ( 13). Paler and Ruckley ( 2001), reported a patient who developed recurrent infestation of otherwise healthy mastoid cavity with storage mite Caloglyphus berlesei ( 14 ). The source of mite in the cases previously reported in the literature include dogs, cats, or farm livestock ( 11 ), damp chicken feed ( 14 ), red poultry [12] and unknown source ( 13 ). Regarding the source of mite infestation in our patient , is interesting to speculate that he acquired it at a lake approximately 24 miles northwest of his former home in Hackensack, New Jersey USA. As noted in his medical history, he frequently visited Shepherd Lake, a popular recreational are in Ringwood State Park, located in the Ramapo Mountains of Passaic County in northern New Jersey, bordering New York State. The 74-acre, spring-fed mountain lake is known for its invigorating cool water that attracts visitors , particularly during the summer months. The patient has often gone swimming there. The condition is very rare in spite of the widespread presence of mites in the environment. Mites live in the dark depths of oceans, bird lungs, on the leaves of rainforest plants and in the pillows beneath our heads. Whenever biologists peered from the floor to facial pores they have found these tiny arachnids. On the basis of reports in the literature and what is known about the feeding habits of histiostomatid mites in general, there is every reason to conclude that these mites are not parasitic and that at best they are facultative commensals, surviving on secretions, exudates, and micrflora in the ears of certain mammals. It is also plausible to believe that the mites are able to gain a foothold and reproduce in ears that are already irritated or infected , rather than that the mites invade healthy ears and cause problems by their presence. The mastoid cavity is considered a hospitable environment for the mites because the cavity is warm, humid and not ventilated [14].Certain occupations may be at a relatively high risk of developing the disease. Mite infestation of the ear was reported in bird handlers who come in contact the infested birds or their feeds. [12],[14]. The histopatholo- gy of “ human otoacriasis” has not been reported in the literature. However, Degiorgis et al [15], reported the histopathological appearance observed in three freeranging Eurasian lynx ( Lynx lynx) killed in Sweden and were found to have mite otoacriasis caused by Otodectes cynotis. There was hyperkeratosis and acanthosis, and the epithelial surface was overlapped by hyperkeratotic and parakeratotic crusts with mite detritus and cerumen. The subcutis showed slight to moderate infiltration of lymphocytes and macrophages. The cerumenous glands were hypertrophic and hyperplastic. There was also hyperplasia of the sebaceous glands. The Lesions seemed to correlate with the degree of infestation. The diagnosis of mite otoacri-asis is usually established by the direct microscopical ear examination. This demonstrates the crawling mites in the ear canal. Detection and identification of mites may also be accomplished by ear scrapings or sampling an oil-soaked cotton swabs for in vitro microscopic examination. Crusts removed from the ear could be soaked in chlorallactophenol ( equal volumes of chloral hydrate, lactic acid and phenic acid ) and examined microscopically for the presence of the parasites [11]. Treatment of the condition is simple. Initial treatment involves thorough cleaning of the canal from all the mites and debris. This is best performed with the aid of the surgical microscope and may have to be repeated after 7 to 10 days. Topical drops of suitable insecticide like alcoholic ear drops [11], Eurax® ( 10% Crotamiton USP) or Permethrin 1% [12] may be used. Non- steroidal anti-inflammatory agents may be administered to reduce pain and edema. Recurrent infection has been reported. In one patient, examination carried out one year following treatment showed the presence of laravae and eggs (11 ). In another occasion, the ears were reinfested for times despite adequate treatment. This was attributed to the presence of mastoid cavities in addition to repeated contact with the mite source [14]. Control of mites on animals or in the environment usually requires the use of approved pesticides or drugs. The choice of which pesticide to use, or which drug will, will vary with the mite and the animal infested. Pesticides that are used to control mites or ticks are called acaricides.

In conclusion , the symptoms of mite otoacariasis are similar to those of a common otitis externa.. The condition may pose difficulty in diagnosis because the live mites are not recognized clearly by the naked eye. It is quite possible that the condition is more frequent than suspected, and that diagnosis could be made more often if the microscope is used in the evaluation of all cases of otitis externa. Treatment is by meticulous ear toilet with the application of appropriate drops.

  References Top

Al-Arfaj A, Mullen GR, Rashad R, Abdul-Hameed A,O’Conner B, Alkhalife Is,et al. A human case of otoacariasis involving a histiostomatid mite ( Acari:Histiostomatidae). Am J Trop Med Hyg.2007;76:967-71.  Back to cited text no. 1
Naude TW, Heyne H, van der Merwe IR, Benic MJ.Spi-nose ear tick, Otobius megnini (Duges,1884) as the cause of an incident of painful otitis externa in humans. J South Afr Vet Assoc. 2001;72:118-119.  Back to cited text no. 2
Hazchzermeyer HF. Another hynab ear case. J South Afr Vet Associ.2002;73:2.  Back to cited text no. 3
Van der Mewee IR, Benic MJ,Naude TW,Heyne H. Spi-nose ear ticks as the cause of an incident of painful otitis externa. South Afr Med J. 2002;92:712-713.  Back to cited text no. 4
Fegan D,Glennon J. Intra-aural ticks in Nepal. Lancet.1996;348:1313.  Back to cited text no. 5
Burchard L,Larena N,Ramos P. Human otoacariasis caused by Otobius megnini in Calama, Chile. Bol Chil Parasitol.1984;39:15-16.  Back to cited text no. 6
Indudharan R,Dharap AS, Ho TM. Intra-aural tick causing facial palsey. Lancet.1996;248:613.  Back to cited text no. 7
Indudharan R,Ho TM,Salim R,Htun YNH.Human otoacariasis. Ann Trop Med Parasitol. 1999;93:163167.  Back to cited text no. 8
Dilrukshi PR,Yasawardene AD,Amersinghe PH,Amersinghe FP.Human otoacariasis: ;a retrospective study from an area of Sri Lanka. Trans R Soc Trop Med Hyg.2004;98:489-495.  Back to cited text no. 9
Eads RB,Campos EG.Human parasitism by Otobius megnin( Acari Argasidae)in New Mexico,USA. J Med Entol.1084;21:244.  Back to cited text no. 10
Van der Heyning J,Thienpont D.Otitis externa in man caused by mite Otodectes cynotis. Laryngoscpe.1977;87:1039-41.  Back to cited text no. 11
Rossiter A. Occupational otitis externa in chicken catchers. J Laryngol Otol.1997;111:366-367.  Back to cited text no. 12
Cho JH,Kim JB, Cho CS,Huh S, Ree HI. An infestion of the mite Sancassania besrlesei ( Acari: Acaridae) in the external auditory canal of a Korean man. J Parasitol.1999;85:133-134.  Back to cited text no. 13
Paleri V,Ruckley RW.Recurrent infestation of the mastoid cavity with Cytoglphus berlesei: An occupational hazard. J Laryngol Otol.2001;115:652-153.  Back to cited text no. 14
Degiorgis MP,Segerstad CH,Christensson B,Morner T. Otodectic otoacariasis in free-ranging Eurasian lynx in Sweden. J Wild Dis.2001;37:626-9.  Back to cited text no. 15


  [Figure 1], [Figure 2]


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