EFFECTS OF SKUNK SPRAY
Although pet owners seldom witness their pets being sprayed by a skunk, the odor is immediate and unmistakable when spraying
occurs. Ocular edema, conjunctivitis, drooling, and squinting are commonly noted in animals that have been sprayed. Many dogs
will rub their faces, roll, sneeze, and vomit. Temporary blindness may occur.
Exposure to skunk spray can be oral, dermal, ocular, and respiratory. Dermal absorption of the spray is minimal. The severity
of signs may depend on a pet's proximity to a skunk when being sprayed and the area of exposure (face vs. legs or side). If
an animal is sprayed directly in the face, inhalation can occur.
In rare instances, Heinz body anemia, methemoglobinemia, and hemoglobinuria may occur a few hours to 24 hours after exposure
(ASPCA Animal Poison Control Center Antox: Unpublished data, 2011).5 In these cases, the thiols in the skunk spray cause oxidative damage to hemoglobin. The thiols react with oxyhemoglobin
in an oxidation-reduction reaction. This reaction forms methemoglobinemia, thiyl radicals, and hydrogen peroxide. Thiyl radicals
and hydrogen peroxide are highly reactive and combine with hemoglobin sulfhydryl groups, resulting in Heinz bodies and subsequent
hemolysis. (Other substances that cause oxidative damage to red blood cells include onions, garlic, acetaminophen, benzocaine
and other local anesthetics, naphthalene moth balls, and zinc.5)
Although there are no reports of a cat developing methemoglobinemia from skunk spray, feline red blood cells are more sensitive
to oxidative damage than are the red blood cells of other species. Cats have eight free sulfhydryl groups on their hemoglobin
(versus four in dogs), which results in increased susceptibility to oxidative damage.6,7 Japanese breeds of dogs (Tosa, Shiba Inu, and Akita) are more susceptible to oxidative damage to red blood cells compared
with other breeds of dogs.8
CASES OF SKUNK SPRAY TOXICOSIS
The ASPCA Animal Poison Control Center's toxicology database from November 2001 to May 2011 included cases of 107 patients
(102 dogs and five cats) that were exposed to skunk spray and that developed clinical signs. Only those signs assessed as
having either medium or high likelihood of resulting from the skunk spray were included. Most dogs had mild clinical signs.
Clinical signs reported in the cats included odor, conjunctivitis, and squinting.
A search of the literature revealed only one report of Heinz body anemia in a dog after exposure to skunk spray.5 Two cases were identified in the ASPCA toxicology database. One involved a 2-year-old 34.5-lb (15.63-kg) neutered male Pharaoh
hound that was sprayed heavily in the face. Initial Heinz bodies were noted three to four hours after exposure and continued
to worsen during the subsequent 12 hours. The dog developed mild to moderate Heinz body anemia but recovered with symptomatic
and supportive care. The dog was released to the owner the next day.
A second case involved a 5-year-old 38.6-lb (17.5-kg) intact male boxer. The dog had a history of being sprayed by a skunk
five times before, although it is unknown how close together the incidences occurred. The dog escaped from the house and when
the owner found the dog the next morning, the dog smelled strongly of skunk spray and was tremoring. The dog was brought to
an emergency clinic more than 12 hours later. Nearly 100% of the red blood cells studied contained Heinz bodies. Results of
laboratory testing confirmed methemoglobinemia. The dog had a seizure and died. The owner requested cremation and did not
authorize the release of histopathologic and other diagnostic findings. To our knowledge, this is the only death related to
a skunk spray in a dog (ASPCA Animal Poison Control Center Antox: Unpublished data, 2011).