What makes my dog itch?
By Henry Cerny, DVM, MS
If your dog is frequently scratching, you may suspect a problem with fleas. But fleas are far from the only cause of skin irritations and itches.
Insect bites and stings are fairly common on dogs. Some cause minimal to no symptoms, while others can cause a life threatening allergic reaction. The most common signs of an insect bite are redness and swelling at the site of the bite. In more severe reactions, hives may appear along with swelling of the face and muzzle. If a dog is sensitive to proteins in the insect's venom or saliva, you may see more obvious signs such as vomiting, difficulty breathing, and in some cases, death.
Flying insects such as bees and wasps are active in the spring and summer. When sniffing an insect, dogs are often stung on the muzzle. A sting in the mouth is frequent when a dog snaps at or bites a bug. If a stinger is visible, remove it with tweezers and apply of a topical antibacterial ointment is beneficial.
The majority of spiders in North America are not poisonous, but bites can still cause localized swelling and pain. However the brown recluse, black widow and hobo spider are poisonous and bites can be very serious. The brown recluse as well as the hobo spider's venom causes localized tissue necrosis (death) leaving a dark ulcer that is slow to heal. Black widow spider bites may cause minimal swelling at the site, but can cause intense pain and even paralysis lasting up to 48 hours.
Ticks not only can cause swelling at the site, but can carry diseases. Exercise great care when removing a tick. If you are squeamish, spray the ticks directly with a dog approved tick spray and let the tick die before removal. Using tweezers or a tick scoop, grasp the tick by the head and pull straight up. Do not pull the tick by the body as this may release bacteria into the bloodstream and leave the head and mouthparts still in the skin. The best defense against ticks is prevention. There are several good flea and tick products on the market and your veterinarian can recommend a good one.
Dogs that suffer from flea allergies often bite at their tail and scratch frequently. Hair loss (alopecia) is often seen around and on top of the tail due to the intense itchiness (pruritis) caused by an allergic reaction to the fleas saliva. By spreading the hair or using a flea comb, you may see fleas or black specks that look like dirt. Pick up some of the black specks with a moistened cotton ball and you'll notice a red color because fela dirt is actually digested blood. In flea allergic dogs it is important to treat the dog for fleas and treat the home for fleas in order to relieve an itchy dog.
There are several good products on the market that kill fleas and ticks. It is important to choose a product that kills fleas before they have a chance to bite as it is the saliva that causes the allergic reaction and an itchy dog. I have always had good luck with products.
Regardless of the cause of the allergic reaction, you can try several over the counter treatments. Antihistamines such as Benadryl (Diphenhydramine) can be given at a dose of 0.5 – 1 mg / lb of body weight every eight hours as needed. Drowsiness is the most common side effect. If the irritatedarea is localized a topical product such as hydrocortisone cream can be applied. If the area appears infected, a triple antibiotic ointment like Neosporin may help.
If you do not see improvement within a few hours after the Benadryl or if the allergic reaction is severe or continues to get worse, seek professional veterinary care as soon as possible. Dogs who have noticeable facial swelling, difficulty breathing, pain or intense itching should be seen immediately.