The brown recluse spider holds a certain allure for those interested in arachnids, but for those who care for dogs, caution is advised regarding this particular spider. Bites from a brown recluse can be painful and potentially harmful to canines. Moreover, the symptoms of a brown recluse bite in dogs can be difficult to detect, especially in the early stages. Examining the behavior of these spiders and understanding how to assist a dog that has been bitten is crucial.
Identifying a Brown Recluse Spider
True to its name, the brown recluse is a brown spider that prefers solitude. The Merck Veterinary Manual points out that the spider can be recognized by the violin-shaped marking on its cephalothorax (upper body). However, due to its elusive nature, confirming its presence can be challenging. The brown recluse is inclined to steer clear of both humans and dogs, biting only when provoked. It measures 1 to 1.8 centimeters in length, with legs extending 2 to 3 centimeters. The venom it injects is highly toxic and can cause severe skin damage, leading to tissue death and ulceration, sometimes affecting an area much larger than the spider itself.
The habitat of the brown recluse spans a broad area, including the Midwest of the United States—stretching from Colorado and New Mexico in the west to Northern Georgia in the east—and extending through the southern states and up the Mississippi to Wisconsin.
Recognizing the Clinical Signs of a Brown Recluse Bite
Although a bite from this spider is somewhat unique, the clinical signs in dogs may initially resemble other insect stings or bites. Dogs might not show any obvious symptoms or may exhibit non-specific behaviors such as limping or shaking.
Clinical signs of a brown recluse spider bite in dogs include:
- Mottled and reddened skin with a “bullseye” lesion
- Deep skin ulcers
Less common reactions to a brown recluse bite in dogs can involve systemic responses to the venom, such as:
- Fever
- Shaking
- Rashes
- Lethargy
- Weakness
- Nausea
Some canines may suffer from red blood cell damage, leading to anemia and hematuria (blood in the urine), typically within the first 24 hours post-bite. Although rare, the venom can cause serious conditions such as renal failure, gangrene, clotting issues, and severe destruction of red blood cells.
Diagnosing a Brown Recluse Bite on a Dog
Dog owners often notice the bite due to localized pain or itchiness. Veterinarians will focus on the affected area, possibly shaving the fur to look for signs of a bite. Initially, bites from other insects or animals may be confused with those of a brown recluse. Once the characteristic bull’s-eye and eschar develop and tissue sloughing occurs, suspicion typically turns to a spider bite.
Laboratory analysis, which might reveal changes in red blood cells, certain white blood cells, and platelets, as well as blood in the urine, can assist in confirming a diagnosis.
Treating and Preventing a Brown Recluse Bite on a Dog
Treatment targets the lesion with antibiotics, pain relievers, corticosteroids, and topical treatments to maintain hygiene and reduce pain, inflammation, and infection. Cold packs can be beneficial early on, and Dapsone is the preferred medication to mitigate the local and systemic effects of the venom, but it should be administered promptly. Recovery may be protracted if severe tissue damage has occurred, often taking several weeks. Surgery might be necessary to remove dead or infected tissue, which is particularly important if gangrene is a risk.
Prevention of brown recluse bites involves keeping dogs from exploring underbrush off trails or while camping in areas where these spiders are known to live. If residing in a region with brown recluses or noticing symptoms of a bite, dog owners are urged to contact their veterinarian immediately.
Contributor Bio
Dr. Patty Khuly is an acclaimed veterinarian recognized for her independent thought, strong advocacy for pets, enthusiasm for the veterinary field, and her distinctive approach to pet health writing. Dr. Khuly graduated with honors from Wellesley College and the University of Pennsylvania School of Veterinary Medicine and obtained her MBA from The Wharton School of Business as part of an esteemed VMD/MBA dual-degree program. She currently operates Sunset Animal Clinic, her own veterinary practice in Miami, Florida. Her writings can be followed at DrPattyKhuly.com and sunsetvets.com.
