Anaphylactoid purpura in a horse.

This research article presents a case of an 8-year-old horse that developed symptoms and physiological conditions strikingly similar to anaphylactoid purpura, a disease more commonly seen in humans.

Introduction and Presentation

• An 8-year-old gelding, which had been suffering from a persistent streptococcal respiratory infection, developed symptoms of shortness of breath (dyspnoea) and abdominal pain (colic).

Surgical Findings

• Upon performing a surgical exploration of the abdomen (laparotomy), the surgeons discovered multiple distinct areas of necrosis – tissue death – throughout the horse’s digestive tract. These areas, thick and hemorrhagic, were imposing severe adverse impacts on the horse’s health.

Postmortem Examination

• Following the death of the gelding, a postmortem examination was carried out. The examination revealed that the same kind of necrotic lesions were also present in the laryngeal mucosa (lining of the larynx or voice box) and in many of the horse’s skeletal muscles.

Microscopic Analysis

• Upon inspection at the microscopic level, these lesions were found to be characterized by widespread tissue death and bleeding. Additionally, a manifestation of leukocytoclastic vasculitis was identified in the tissues adjacent to the lesions. Leukocytoclastic vasculitis refers to inflammation and eventual damage to blood vessels.

Diagnosis

• The overall presentation of symptoms and findings bore striking resemblance to anaphylactoid purpura (also known as Henoch-Schönlein disease) in humans. Anaphylactoid purpura is an immune-mediated condition often triggered by infections, leading to inflamed blood vessels often causing skin, kidney, and gastrointestinal issues.

Exclusion of Fungal Infection

• Despite the respiratory infection, the diagnosis of a fungal infection was ruled out. This determination was confirmed by the utilization of special staining techniques, which showed no evidence of fungal elements in the forms of spores or fungal filaments within the examined tissues.