There are many reasons why your dog may be itchy. It could be due to skin disease, parasites or allergies. Skin disease is a common cause that may cause your dog's skin to become red, swollen, itchy, peeling, or have pustules. Skin diseases may be caused by bacteria, fungi or parasites, or may be due to allergies or malnutrition.
Parasite may also be the cause of itching in dogs. Parasites include mosquitoes, lice, fleas, worms, etc. Dogs may develop ticks or fleas, or be bitten by mosquitoes. Allergies are also a common cause. Dogs may be allergic to food, medications, or certain substances in the environment, causing their skin to become itchy, swollen, or red. If your dog is itching all the time, it is recommended to take it to a veterinarian so that a professional can determine the cause and provide appropriate treatment.