Peer-reviewed veterinary case report
Injection site eosinophilic granulomas and collagenolysis in 3 horses.
- Journal:
- Journal of veterinary internal medicine
- Year:
- 1999
- Authors:
- Slovis, N M et al.
- Affiliation:
- Veterinary Medical Teaching Hospital · United States
- Species:
- horse
Plain-English summary
Three horses developed raised bumps on their skin within a day or two after receiving injections with standard silicone-coated needles. A skin sample from each horse was taken to check for any underlying issues, and it showed that these bumps were likely caused by a type of allergic reaction known as equine eosinophilic granuloma. To further investigate, two of the horses were injected again, this time with both coated and non-coated stainless steel needles, and biopsies were taken two weeks later. The areas where the coated needles were used showed significant inflammation and damage to the skin tissue. This suggests that the horses had an unusual immune response to the silicone coating on the needles.
Abstract
Three horses were presented with a history of having developed raised cutaneous nodules, within 24-48 hours, in areas of previous injections using standard silicone-coated hypodermic needles. Skin biopsies were taken from a selected cutaneous nodule from all horses for histopathologic evaluation. Histologically, the nodules were consistent with a diagnosis of equine eosinophilic granuloma. A hypersensitivity reaction to the silicone, or another component of the coating formulation, was hypothesized to be responsible for these lesions. Two horses were experimentally injected using both coated and noncoated stainless steel hypodermic needles and skin biopsies were obtained 14 days after injection. The sites of the coated needle injections were characterized by severe eosinophilic granulomatous inflammation with and without collagenolysis. The eosinophilic granulomas with and without collagenolysis observed in these horses are proposed to represent a complex immunologic response to the silicone-based coating of most hypodermic needles.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/10587264/