Sarcoptic mange is an extremely irritating, highly contagious skin condition of dogs that occurs when microscopic female mites burrow into a dog's skin to lay their eggs.
The Sarcoptes scabiei var. canis mite is the culprit for this type of mange. The name probably reminds you of the human disease scabies. You're on the right track. The mite variety that affects dogs doesn't thrive on human hosts, but some owners of affected dogs develop rashes on their arms, chest, or belly. The rash should disappear after the dog undergoes treatment.
Risk factors and detection
Sarcoptic mange affects any age and breed of dog, but it's most common in free-roaming dogs and those in close confinement, such as animal shelters.
Signs of infection include intense scratching, chewing on the skin, and scattered hair loss with a rash appearing on the belly, chest, legs, or ears.
These signs mimic several other skin diseases, including food allergies or inhalant allergies, flea allergy dermatitis, and bacterial infections. Contact your veterinarian immediately if your dog has any of these symptoms. Sarcoptic mange isn't life-threatening, but it's highly contagious, and it makes your dog miserable.
During the examination, your veterinarian might rub your dog's ear margin—where the ear meets the head—to see if his rear leg starts scratching. This "pinnal-pedal" reflex is a common sign of sarcoptic mange.
The doctor may try to find mites by microscopically examining skin scrapings, but veterinarians can't always recover them because they burrow so deep. If your veterinarian can't detect the mites but still suspects sarcoptic mange, he or she may treat your dog for the problem anyway. If the itching goes away, then you know sarcoptic mange was the culprit.
Prevention and treatment
Short of isolating your dog from the world, there's no guaranteed prevention. However, sarcoptic mange is easily treated with injections or topical parasiticides. Treatment also may include a weekly bath for three to five weeks with a medicated shampoo to remove scales and scabs. Your veterinarian will recommend a product.
One treatment involves two injections or oral doses of ivermectin administered two to three weeks apart. However, ivermectin isn't FDA-approved for treating sarcoptic mange, so discuss this option with your veterinarian. He or she also will make sure your dog is heartworm-free before treating with ivermectin. Collies, Old English sheepdogs, Shetland sheepdogs, Australian shepherds, and their crossbreeds show extreme sensitivity to ivermectin, so your veterinarian will choose a different treatment option for these dogs.
The newest way to treat and prevent recurrence is a broad-spectrum topical parasiticide called selamectin, which is FDA-approved and available from your veterinarian. One or two monthly treatments kill the mites and relieve itchiness in about 90 percent of dogs. Best of all, this drug is safe for ivermectin-sensitive breeds.
Your veterinarian may prescribe corticosteroids, such as prednisone, if the itchiness is severe or persistent. Dogs who develop a secondary bacterial infection also need two to three weeks of antibiotic therapy.
