Anaphylaxis is a sudden and severe allergic reaction to a foreign compound introduced into the body. The difference between Anaphylaxis and a common allergy is the common allergy appears slowly, taking the form of a rash and itching, respiratory congestion or diarrhea. Symptoms of anaphylaxis occur within one hour of exposure to the allergen, but more often than not within thirty seconds. In severe cases of anaphylaxis, the first sign is a rapid drop in blood pressure causing paleness of the gums and breathing difficulties. Dogs often urinate, deficate and vomit in response to the histamine release. Heartbeat is often rapid, weak, or irregular. The pets appear uncoordinated, restless and frightened. Bloody diarrhea may follow. When swelling of the larynx occurs pets can die due to an inability to breathe. In the most severe cases, shock, manifested by collapse, convulsions and coma, soon follows. Some pet’s temperature falls to subnormal while others run fevers. Adjuvants are compounds added to vaccines to increase their overall effectiveness. Intervet & Heska are two companies that offer a non-adjuvanted 3-year vaccines. They contain none of the adjuvants that may cause cancer or immunological disease later in life. This change in vaccines will help but even non-adjuvanted injectable vaccines are not risk-free. An allergen is any substance that causes a reaction; substances that the immune systems of a few animals and people recognize as "foreign" or "dangerous" but which cause no response in the majority of pets and people. An anaphylactic allergen can be a drug, insect sting, ingredient in food, a vaccine component, or a cosmetic ingredient. Allergens cause the body to chemically react producing substances inside the body that cause changes in heart function, blood pressure, blood vesicle permeability as well as injury to surrounding tissue. These are the visible signs of anaphylaxis. There are two forms of anaphylaxis: true anaphylactic reaction and anaphylactoid (anaphylactic-like) reactions. Clinically, it is difficult to distinguish between the two.
If your pet has had prior vaccine reactions, think seriously before having any vaccines administered. A vet will insert a tube in the windpipeif the pet is having difficulty breathing through its swollen larynx. A drop in blood pressure and circulatory collapse starves the body of oxygen and must be quickly corrected. The liver and intestines are specifically affected. Capillary blood vesicles become more permeable, leaking blood serum into the tissues. Intravenous fluids must be given rapidly, in large quantities to counteract this. Dogs must be closely monitored so as not to over-flood their lungs with fluid (pulmonary edema) Saline solutions such as Ringer’s solution should not be given at a rate over 20-25ml/pound/hour. One very good sign is urination, proof that fluid correction is sufficient. Colloidal fluids such as the polysaccharide, dextran (2.5-5ml of Dextran70 solution / pound body weight IV over 5-10 minutes) or hetastarch, are preferable to saline solutions because they do not leave the circulation (leak) as rapidly as Ringer’s solutions. Dogs need to immediately receive injections of epinephrine (1.25-2.5 micrograms/pound IV). This compound is produced by the adrenal gland normally, and increases heart rate and blood pressure while slowing mast cell disintegration. Oxygen therapy is also helpful, as is the intravenous administration of rapid-acting steroids such as prednisolone sodium succinate (SoluDeltaCortef, 7.5-15mg/pound) or dexamethasone sodium phosphate (Decadron, 1-2mg/pound). At the same time the pet should receive an injection of antihistamine (chlorpheniramine maleate, Chlor-Trimeton 0.25mg/pound) or diphenhydramine (Benadryl, 0.5 mg/pound). If dog is hypothermic (low body temperature) keep very warm. Dogs with a body temperature above 105F should be rubbed down with iced water. It is also wise to give these pets one of the penicillin-derived antibiotics to prevent secondary infections related to increased intestinal and pulmonary permeability. Dogs can die or be left severely impaired. The liver suffers greatly during anaphylactic shock. It is considered the major “shock organ” of the body. This is because the liver cells are very sensitive to inadequate oxygenation and edema. The loss of blood supply (ischemia) to the stomach and small intestine can result in necrosis (death) of the cells that line these organs forming bleeding ulcers. Dogs vomit bloody mucous and/or pass blood in their stools. In some cases bacteria gain access to the abdominal cavity (peritonitis) through these ulcerated areas. In some cases entire segments of the intestine die. Another result of anaphylaxis is called disseminated intravascular coagulation. In this condition, pooled blood coagulates within the vessels of the circulatory system leading to a deficiency in platelets. Without sufficient platelets, hemorrhages occur throughout the body. This can also be fatal.