Leucocytoclastic vasculitis associated with Staphylococcus intermedius in the pastern of a horse.

The research study revolves around a case report where a pregnant horse developed sudden and severe lameness due to a swelling in its hind leg, later identified as leucocytoclastic vasculitis brought about by Staphylococcus intermedius infection, commonly known to cause pastern dermatitis in horses.

Introduction and Case Presentation

• The article discusses a case of a quarterhorse mare that was found to suffer from acute lameness due to intense swelling in its right hind leg. Initial conjectures pointed towards a fracture or a muscle tear causing the lameness.
• A physical examination was conducted on the horse which revealed the presence of chronic pastern dermatitis, also known as ‘scratches’ or ‘grease heel’.

Diagnostic and Evaluation Process

• Despite the swelling seen on the horse’s right hind leg, the diagnosis investigations did not indicate any traumatic musculoskeletal causality.
• In order to identify the cause of the abnormality, the researchers conducted a histopathological evaluation on the biopsy samples taken from the affected area of the hind leg.
• This evaluation showed results consistent with leucocytoclastic vasculitis, a type of small-vessel vasculitis resulting from inflammation of blood vessels.
• Further, they also conducted a culture of the biopsy sample which yielded Staphylococcus intermedius, confirming the organism as a causative agent.

Discussion and Conclusion

• After confirming the cause of the inflammation and related lameness, the researchers moved towards discussing the treatment and possible infectious triggers of pastern dermatitis in horses.
• This case study provides important insights into the manifestation of leucocytoclastic vasculitis in horses and its association with Staphylococcus intermedius infection.
• It also underscores the importance of accurate diagnosis for targeted treatment strategies and can guide further research to manage or prevent similar cases in horses.