Hypersensitivity Reactions in Critically Ill Dogs

Type III hypersensitivity reactions are delayed immune responses to an antigenic substance. Immune complexes from this reaction can deposit in blood vessel walls, glomeruli, and synovia. This causes a cascade of responses that can lead to vasculitis, glomerulonephritis, or arthritis. Type III hypersensitivity reactions to human serum albumin (HSA) have been documented in healthy dogs. Clinical signs can include lethargy, edema, vasculitis, ecchymoses, lameness, fever, vomiting, hypovolemic shock, oliguria, and death. HSA is used in humans and dogs to treat significant hypoalbuminemia.

The authors described the first documented cases of a type III hypersensitivity reaction occurring in critically ill dogs given HSA. Case 1 described a 6-year-old spayed rottweiler with a septic abdomen caused by small intestinal perforation. The dog was taken to surgery, developed hypoalbuminemia, and was treated with HSA. Sixteen days later, the dog developed signs of a type III hypersensitivity reaction. Case 2 described a 10-year-old castrated Norwegian elkhound that had surgery to remove an intestinal foreign body and was treated with HSA (also for hypoalbuminemia). The dog developed signs of a type III hypersensitivity reaction 8 days later. Skin biopsies from both dogs showed epidermal pallor, edema, hemorrhage, degenerative neutrophilic perivascular infiltrates, and multifocal areas of neutrophilic or leukocytoclastic vasculitis. Immunohistochemical staining also suggested HSA antigen–antibody complex deposition in the dermis. Treatment for the reactions included steroids and antihistamines; both dogs recovered from the hypersensitivity reactions with no further sequelae.

Commentary

HSA has previously been reported to cause delayed hypersensitivity reactions in healthy dogs. There is a common perception that critically ill dogs are not susceptible (or at least less susceptible) to the development of hypersensitivity reactions after HSA infusion. This article provided a nice summary of type III hypersensitivity reactions and described 2 dogs that postoperatively received HSA for treatment of severe hypoalbuminemia. Both dogs developed peripheral edema and skin biopsies and both cases showed convincing evidence of a type III hypersensitivity reaction. The importance of this case report is centered on the demonstration that critically ill dogs are also susceptible to the development of hypersensitivity reactions.

—Daniel S. Foy, MS, DVM, DACVIM, DACVECC

Source

Type III hypersensitivity reaction with immune complex deposition in 2 critically ill dogs administered human serum albumin. Powell C, Thompson L, Murtaugh RJ. JVECC 23:598-604, 2014.