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Strangles, a common cause of purpura hemorrhagica, is an upper respiratory disease caused by an infection of the Streptococcus equi bacteria. This highly infectious condition causes fever, runny nose or eyes, and swelling of the lymph nodes in the jaw or throat areas so severe as to cause difficulties in swallowing and breathing. Purpura hemorrhagica can develop as the bacteria moves to other body systems. While strangles is highly contagious, purpura hemorrhagica is not, and affected horses cannot infect healthy horses.
Purpura hemorrhagica is an immune mediated condition caused by vasculitis, or an inflammation of the blood vessels. This causes bleeding and swelling and is believed to be an allergic reaction to a previous infection of any streptococcal bacteria, such as strangles, or a virus. The resultant swelling can be a source of discomfort and lameness for your horse and needs immediate medical attention to prevent such serious complications as bowel hemorrhages, renal failures, and death.
Signs begin with skin complaints and swelling in various body areas from the inflamed blood vessels, but can rapidly progress to organ failures and death as the condition spreads to wherever the blood vessels travel. You may not see any signs of the condition until 2 to 3 weeks after infection. Symptoms include:
Purpura hemorrhagica is believed to be an immune response to a previous infection, which causes the overproduction of antibodies that deposit onto the walls of blood vessels. These blood vessels then hemorrhage into surrounding tissues, which causes various swelling and other symptoms seen. Causes that can trigger this particular immune response include:
A diagnosis is based on clinical signs, a history of a prior exposure to strangles or other bacterial or viral infections, a physical examination, and the results of testing. Blood tests can show the presence of Streptococcus equi antibodies. Skin biopsies can reveal signs of vasculitis. Other tests include a CBC and serum analysis.
Treatment aims to reduce the immune system response while removing the cause that triggered it. Corticosteroids are prescribed to reduce inflammation and suppress the immune response. Antibiotics are also given to eliminate the causing infection, as well as to protect your horse against new infections while the immune system is compromised. Antibiotic therapy is often targeted against the strangles bacteria and can last for 2 to 4 weeks.
Other supportive care includes cold water hosing, hydrotherapy, support wraps and bandaging, NSAIDS, drainage of any abscesses, and the administration of gastroprotectants and intravenous fluids. Hand walking and paddock turnout can help to reduce swelling. More severe cases of purpura hemorrhagica may need many more weeks of therapy.
Recovery of your horse can vary, depending on the severity of the condition. Mild cases with rapid treatment can have a good prognosis. More severe cases may be fatal, or require euthanization. The presence of leg swelling can prolong recovery and cause permanent musculoskeletal damage. Timely treatment is necessary for the recovery of your horse.
Your horse is at a higher risk for purpura hemorrhagica if he has had or been exposed to the strangles bacteria, or was vaccinated against strangles while his antibody levels were high. Talk with your veterinarian about the possibility of your horse developing this condition, especially after a previous strangles infection.
Prevent most cases of purpura hemorrhagica by reducing your horse’s exposure to the strangles bacteria. This can be achieved through biosecurity measures such as:
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1 found helpful
I am in true belief that my horse has purpura Hemorrhagica. We are treating with bute am and banamine pm. It’s not working I think her symptoms are worsening. We have confirmed cases of strangles in our Barn. I am confident she did contract it. Green/ yellow discharge from nose with a tinge of blood. Well the swelling in her legs is worsening...day 6 ...not confident my vet is doing everything we can. She has been on bute am and banamine pm I myself have been using water therapy. Well in the past 3 days she has started having drainage from her legs swelling goes down with her walking/turn out in arena but today the weeping in her legs was so bad she wouldn’t walk. I have been reading . They just called the barn owner and said to start dexamethasone. This is what I’m reading now. I am afraid I will loose her. She has never been vaccinated for strangles or been exposed . I have owned her for 20 yrs bought her as a 2yr old. Help! I am a vet tech with dogs and cats by trait!
Jan. 17, 2018
Dr. Michele K. DVM
Thank you for your email. Without seeing Angel, I'm not sure that I can comment much on what might be going on with her. If you feel that your veterinarian is not doing everything possible, it never hurts to get a second opinion, as different minds think differently. She does sound like she needs further diagnostics or treatments - maybe it is possible to have a referral to a specialty hospital? I hope that she is okay.
Jan. 18, 2018
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My mare has been diagnosed with Purpura Hemorrhagica as per results of biopsy of tissue from her swollen limb. She has been being treated for the last three months with Dex, and Baytril IV for 10 days straight . Then continued with Pred at a rate of 25 tabs a day for approx. two weeks and started reducing by two every 5 days. The mare had a flare up with fever again approx. two weeks after off the baytril. We then treated her with Exceed 15ml first day and 15 ml four days out. We then proceeded to give exceed once a week at 15ml till bottle was used up. The mare is still swelling up in her joints and limbs and is painful. She was never exposed to strangles or was not vaccinated for it as well. This entire episode came out of the blue but we were able to properly diagnose with biopsy. I am starting to feel hopeless at this point . Any thing that we may be missing that could possibly help I would love to hear. We have also done extensive cold hosing, poulticing and hand walking to try and take swelling down. It will go away for a bit but then returns.
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