Brown Recluse Spider Bites in Dogs

The brown recluse spider is 1/2 inch to 2 inches (1.2 cm to 5 cm) long. They are usually identified by a distinctive fiddle-shaped mark on their back. The brown recluse spider is present throughout the United States, especially through southern United States. They tend to hide in dark, secluded areas and usually only bite when they feel they are threatened or their area is invaded. Bites often occur when spider is trapped in bedding. 

The specific type of venom of the brown recluse spider is not fully understood, and the toxicity is not clear except it is known to destroy the tissues surrounding the bite.

Usually, the dog does not realize he has been bitten. A while after the bite, a reddened area develops, sometimes accompanied by fever and nausea.. The primary damage is specific to the area around the bite. Underlying muscle tissue may die and become infected, and some bleeding in the area may occur. With or without treatment, the wound may take weeks to heal.

Veterinary care is generally recommended to prevent additional tissue damage.

What to Watch For

Pain at the area of the lesion

Lesion with a central dark area

Skin sloughing

Fever

Chills

Rash

Diagnosis 

Diagnosis is based on the appearance of the skin wound and the possible access to brown recluse spiders.

Treatment 

Generally, pets do well and recover from brown recluse spider bites but full recovery may take weeks. Treatment for brown recluse spider bites is aimed at treating the skin wound. Options may include: 

Antibiotics to prevent infection 

Sometimes, if other treatments do not heal the wound, surgery may be needed to remove the skin surrounding the affected area. 

If fever and nausea develop, treatment may be required to alleviate these symptoms. 

Home Care and Prevention

The initial home care is to clean the skin wound with hydrogen peroxide, chlorhexidine or povidone iodine. Do not use a tourniquet since the venom stays primarily in the area of the bite and tourniquets can cause significant circulation damage. 

If the wound becomes larger or persistent drainage occurs, veterinary care is recommended. If lethargy, vomiting or nausea occur, there is no home care and seeking veterinary assistance is strongly recommended.

The primary prevention is to limit your pet's access to brown recluse spiders. Check areas of your house that are prime brown recluse spider hiding areas such as dark basement corners and rarely used closets. If you notice brown recluse spiders, consider consulting an exterminator to remove the spiders from your home.