Parasites like fleas and ticks can invade your dog's skin causing irritation and discomfort. In response to this, your dog can start scratching, licking, or chewing the affected skin. Parasitic invasion followed by scratching (by the dog itself) will break the protective skin barrier leading to secondary infections.
External parasites can cause serious illness therefore it is the best approach to keep your pet safe and protected even when you can't find any ectoparasite on their skin.
Internal parasites are equally dangerous for the health of your pet dog. For example, hookworms and roundworms get their nutrients by leaching into the gut of the dog (host). Therefore a dog with worm infestations will get weaker by losing essential nutrients. It is important to deworm your pet regularly and also test your dog's stool for worms annually.
Work with your veterinarian Frisco TX in creating a health preventive program that includes your pet's year-round protection against internal and external parasites.