Morbus maculosus

Also known as: Purpura haemorrhagica — Purpura hemorrhagica

Introduction

Purpura hemorrhagica is a syndrome of cutaneous vasculitis, deposition of circulating immune complexes of IgA can be seen. This condition is associated with S.equi infection of the upper respiratory tract and mostly occurs following strangles or equine influenza.

Although it is very rare, it is very serious and potentially life threatening.

Signalment

It is an acute non contagious disease of horses.

Clinical Signs

Purpura haemorrhagica is characterized by head and limb edema which is very extensive, leukocytoclastic vasculitis (hypersensitivity vasculitis ) and petechial hemorrhages on the mucosa, musculature and viscera. Glomerulonephritis can sometimes be seen .

Clinical signs can be seen within 2-4 weeks of the respiratory infection. A common symptom is urticaria, followed by pitting edema of the limbs, head and ventral abdomen. If the head edema is severe it may compromise breathing as well as cause tissue exudation and sloughing. Affected horses usually appear depressed, anorexic and reluctant to move.

Diagnosis

Affected animals are not thrombocytopenic but evidence of inflammation is shown by increased fibrinogen and total plasma protein as well as neutrophilia. A cutaneous biopsy of the affected area can confirm the disease.