Anaphylactic Shock is an acute hypersensitivity reaction. It develops in a horse after being exposed to an allergen that it is highly sensitive to. Penicillin antibiotics, vaccines, and immune serums are allergens most frequently involved in anaphylactic shock. Anaphylaxis is generalized (systemic) or localized. A localized reaction, such as an insect bite can consist solely of itching and swelling around bite site. With systemic reactions, the symptoms become generalized, often appearing elsewhere on the body. A severe systemic anaphylactic reaction is accompanied by sweating, anxiety, difficulty breathing, diarrhea, shock, a drop in blood pressure, collapse and death. Signs are produced by histamine and other vasoactive substances which are released by basophil and mast cells in response to the allergen.
Early recognition is essential to treatment of anaphylactic shock. Difficulty breathing and sudden anxiety following a vaccination or administration of a drug are indications to treat.