What to do about Otodectes?
by Kathryn Kuehl DVM, shelter veterinarian at Dane County Humane Society
What are Ear Mites? Ear mites (Otodectes cyanotis) are a contagious external parasite that colonizes the external ear canals of dogs and cats and causes an intense itchy reaction and dark, dry debris that can appear similar to coffee grounds.
How can I diagnose this? You may choose to treat based on clinical signs alone (debris, intense itching, evidence of scratching/excoriations of the ears and ear base). Definitive diagnosis consists of taking an ear swab and mixing with a small amount of mineral oil on a glass slide. The mites should be easily viewed on the 10x objective (see right). If a more serious infection is suspected (purulent discharge, bad odor, and intense inflammation of the ear canal) and additional swab should be obtained and used to make a regular ear cytology slide to direct appropriate adjunctive treatment. Some shelters will automatically apply a few drops of Animax™ or Otomax™ ointment to severely inflamed ears after obtaining swabs and after thorough cleaning.
Treatment options: There are a variety of effective treatments, but the first step to successful treatment is manual removal of gross debris within the external ear canal. A gentle ear cleaner should be used such as plain mineral oil, Oti-clens™or Epi-Otic™.
Ivermectin 1% solution: This may be given either orally or subcutaneously, although it will be absorbed more rapidly by oral administration. The dose recommendation is 0.3 mg/kg once a week for 2-3 doses. The following chart gives a guideline for the volume of ivermectin based on weight. It is important to remember that some animals can be very sensitive to ivermectin and it has the potential to cause neurological symptoms, especially if overdosed. The symptoms to watch for include lethargy, coma, tremors, seizures or an uncoordinated gait. Acarexx™ is the brand-name topical ivermectin treatment that can be applied directly in the ears. If diluted properly, some shelters use ivermectin topically for treatment, but there can be increased risks for toxicity when there are issues with proper dilution,
What are Ear Mites? Ear mites (Otodectes cyanotis) are a contagious external parasite that colonizes the external ear canals of dogs and cats and causes an intense itchy reaction and dark, dry debris that can appear similar to coffee grounds.
How can I diagnose this? You may choose to treat based on clinical signs alone (debris, intense itching, evidence of scratching/excoriations of the ears and ear base). Definitive diagnosis consists of taking an ear swab and mixing with a small amount of mineral oil on a glass slide. The mites should be easily viewed on the 10x objective (see right). If a more serious infection is suspected (purulent discharge, bad odor, and intense inflammation of the ear canal) and additional swab should be obtained and used to make a regular ear cytology slide to direct appropriate adjunctive treatment. Some shelters will automatically apply a few drops of Animax™ or Otomax™ ointment to severely inflamed ears after obtaining swabs and after thorough cleaning.
Treatment options: There are a variety of effective treatments, but the first step to successful treatment is manual removal of gross debris within the external ear canal. A gentle ear cleaner should be used such as plain mineral oil, Oti-clens™or Epi-Otic™.
Ivermectin 1% solution: This may be given either orally or subcutaneously, although it will be absorbed more rapidly by oral administration. The dose recommendation is 0.3 mg/kg once a week for 2-3 doses. The following chart gives a guideline for the volume of ivermectin based on weight. It is important to remember that some animals can be very sensitive to ivermectin and it has the potential to cause neurological symptoms, especially if overdosed. The symptoms to watch for include lethargy, coma, tremors, seizures or an uncoordinated gait. Acarexx™ is the brand-name topical ivermectin treatment that can be applied directly in the ears. If diluted properly, some shelters use ivermectin topically for treatment, but there can be increased risks for toxicity when there are issues with proper dilution,
Selamectin (Revolution™): This topical flea control product has been approved for treatment of ear mites and may be used as part of the intake protocol for flea control and to serve as a first dose of treatment for mite infestations. Selamectin and ivermectin should never be given at the same time as they are in the same class of drug and this could lead to signs of toxicity mentioned above. If giving this as a first treatment, ear cleaning is still important to complete, and you may follow up in one week with the ivermectin treatment, as described above. For severe infestations a single dose of this product is not likely to fully resolve the infection. Imidicloprid/Moxidectin (Advantage Multi™) has also been approved for treatment of ear mites, but may need to be applied more frequently than once a month or followed by ivermectin to provide adequate treatment for active infections.
Other considerations: It is important to remember that these mites are VERY contagious and can be transferred to other animals by direct contact or fomites, such as shared bedding, cloth toys, etc. Animals with confirmed ear mite infections should be separated from animals that are free of mites until treatment has been completed and repeat ear swabs are negative for mites. When an animal in a group (litter of kittens, for example) is treated for ear mites it should be standard protocol to treat all animals in that group, regardless of the presence or absence of clinical symptoms.
Other considerations: It is important to remember that these mites are VERY contagious and can be transferred to other animals by direct contact or fomites, such as shared bedding, cloth toys, etc. Animals with confirmed ear mite infections should be separated from animals that are free of mites until treatment has been completed and repeat ear swabs are negative for mites. When an animal in a group (litter of kittens, for example) is treated for ear mites it should be standard protocol to treat all animals in that group, regardless of the presence or absence of clinical symptoms.
