Purpura haemorrhagica is the same life-threatening autoimmune reaction that can occur from true strangles infection. When a horse with a particularly high level of antibodies is exposed to the live bacteria or vaccine, the horse’s immune system can have too strong a response, causing it to malfunction and attack itself (aka, an autoimmune reaction). See the Strangles Detail page.
Clinical signs of purpura haemorrhagica include severe swelling of the body due to vasculitis (inflammation of the blood vessels), fever, destruction of necessary blood cells, and coagulopathies (reduced ability to form blood clots).
Symptoms of Purpura Haemorrhagica
Early action is Key! If you see any of these signs after a strangles vaccination or in an un-vaccinated horse, contact your veterinarian immediately:
- Red spotting in the gums and other mucous membranes.
- Swelling of the limbs and head (cellulitis)
- elevated heart and respiratory rate
- reluctance to move
- drainage from lymph nodes
- seeping of serum from the skin
- weight loss
Prognosis is good with early, aggressive treatment—92% according to a study done by: Pusterla, N; Watson, JL; Affolter, VK; Magdesian, KG; Wilson, WD; Carlson, GP (26 July 2003). “Purpura haemorrhagica in 53 horses”. The Veterinary record. 153 (4): 118–21. doi:10.1136/vr.153.4.118. PMID 12918829