Peer-reviewed veterinary case report
Microfilarial dermatitis causing itching in dogs in the western US
By Parsiola, Rebecca et al.·Published in Veterinary dermatology·2026·Dermatology for Animals, United States·View original on PubMed →
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Original publication title: Retrospective Review With Genetic Analysis of Canine Microfilarial Dermatitis in the Western United States.
- Species:
- dog
Plain-English summary
Eight dogs in the western United States were diagnosed with a skin condition called microfilarial dermatitis, which caused severe itching and skin lesions. The dogs were treated with a combination of oral fenbendazole and injectable ivermectin over several weeks. While two dogs fully recovered without any further issues, three experienced side effects from the medications, and one had a recurrence of symptoms after initially improving. This study highlights the importance of identifying the specific parasites causing the skin problems and suggests that the paired treatment could be effective for dogs with this condition.
People also search for: dog skin problems itching treatment · microfilarial dermatitis in dogs · ivermectin for dog skin issues
Abstract
BACKGROUND: Microfilarial dermatitis was described once in dogs of the western United States. The organisms were not identified. HYPOTHESIS/OBJECTIVE: To identify nematodes as a cause of dermatitis and describe clinical features, treatments and therapeutic responses. ANIMALS: Eight client-owned dogs with suspected or definitively diagnosed microfilarial dermatitis based on appropriate clinical history and therapeutic response had skin biopsy samples collected. MATERIALS AND METHODS: Retrospective review of electronic medical records taken between January 2010 and December 2022 from a multicentre dermatology speciality group in the United States for dogs, followed by PCR and genome sequencing of microfilariae from formalin-fixed tissue. RESULTS: Pruritus (eight of eight), plaques (five of eight) and lesions of the head (six of eight) were commonly reported. Four had microfilariae on histopathological evaluation. One sample was genetically consistent with Cercopithifilaria bainae; another was consistent with Onchocerca lupi. Two formalin-fixed paraffin-embedded samples were not available for sequencing. Dogs received oral pulse dosing of fenbendazole (Panacur; Merck Animal Health) (mean 41 mg/kg) at 10-day intervals for 4 weeks and injectable ivermectin (Agri-Mectin; AgriLabs) (mean 0.42 mg/kg) given orally once weekly for 6 weeks. Three dogs had adverse drug events. One dog had recurrent clinical signs after experiencing full resolution. Complete resolution without recurrence was reported in two of eight dogs. The times to complete resolution were 63 days (Dog 5) and 65 days (Dog 3). CONCLUSIONS AND CLINICAL RELEVANCE: This is the first confirmed report of clinical dermatitis secondary to O. lupi microfilariae in a dog, and the second clinical description of canine C. bainae microfilarial dermatitis in the United States. Paired ivermectin and fenbendazole may be an appropriate treatment for suspected or definitively diagnosed canine microfilarial dermatitis.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/40776783/