What Causes The Threat To Health?
Neurotoxin venom is found in black widow spiders and targets the nervous synapses. The dog will experience prolonged involuntary muscle cramping and rapid, shallow breathing. The recluse and hobo spider's have necrotic venom which destroys tissue and cellular structure. Bites caused by necrotic venom are easy to spot. They are itchy, red and bleed irregularly. A cyst will form surrounded by a white ring with a blue center.
How Should I Treat My Dog?
To treat a dog who is unfortunate enough to have been bitten by a venomous spider, place an ice pack on the bite as soon as you can. If it is too late then it would be wise to visit the vet. Here your dog will be prescribed a muscle relaxant (for black widow spider bites) or anti-inflammatory corticosteroids to stop tissue destruction. To reduce swelling and itching, allergy medicine such as diphenhydramine may be administered. Antivenins, usually used on humans, can also be effective in treating spider bites - but always consult your vet before doing so.
Last but not least, it is important that you comfort your dog and keep him or her calm.