Paw Pad Injuries and Infections

Injuries to the paw pad can instantly make your dog limp. Your pet companion may have stepped on a sharp object. Your dog may refrain from putting his full weight on the affected limb. Dog owners must examine the paw pad to determine whether this is the cause. Interdigital dermatitis also causes limping. This infection, which can be triggered by an allergy or injury, occurs between the pads of the paw. The dog licks the affected area, which makes it itch, and over time, a lick-itch cycle develops.

Ruptured Ligaments and Fractures

Your dog may suddenly start to limp after playing a game of fetch. He may have slipped while trying to catch a ball and ruptured a ligament in his knee joint. This condition is most common in young, active dogs. A fracture can be another cause of instant limping in dogs. Your dog may have jumped or fallen from a substantial height, or maybe he was hit by a car. The affected bone may be cracked or completely shattered.

Arthritis

Arthritis, common in large dogs, can cause stiffness, lameness and pain. This condition, which can be caused by everything from joint trauma to hip dysplasia, may affect your dog's behavior and mobility. Arthritis gradually worsens -- your dog may go from a slight limp to refusing to use the affected limb. When exposed to a damp, cold environment, your dog's pain and stiffness may increase. To make arthritis more bearable, your veterinarian may recommend acupuncture, physical therapy, pain medication and weight loss.

Bone Tumors

Bone tumors can affect dogs of all ages, but they are more common in giant breeds. A slight limp can be an indication of a tumor in the bone of the leg. As time progresses, a bone mass may emerge, the leg may appear swollen and fractures may occur. Touching the tumor may be painful to your pet companion. Your veterinarian may recommend amputation and chemotherapy. Even though these may not cure the cancer, they can relieve some of your dog's pain.