Many people assume that when a dog experiences itching, a parasite must be the culprit. Although parasites certainly are a common reason for itchy canines, there are other things that cause skin irritation as well. Here are five common causes of itching.

Parasites. Although parasites are not always the offenders, they do rank high in the causes of itchiness. The two most common parasites are fleas and mites. Fleas can usually be identified by black specks in the dog's fur. You may even see the fleas themselves scrambling for cover as you groom your dog.

Mites, including ear mites, fur mites, scabies, and mange are often harder to identify because they burrow under the animals skin and thus cannot be seen. You may notice a red rash, discharge around the dog's ears, or what appears to be dandruff on your dog's coat. If you suspect a mite problem, check with your veterinarian for advice on proper diagnosis and treatment.

Environment. Have you ever rolled around in sand at the beach and then found yourself scratching for the rest of the day? The same thing can happen to your dog. Rolling around in grass, fur, or sand may cause itchiness that can be alleviated by a nice cool bath.

Fur mats, thistles, or anything else that sticks in the fur and pulls at the skin can also be an irritant. Grooming your dog should alleviate these problems.

Nutrition. Dogs require a high quality meat-based diet, and if they don't get it, they are likely to develop a number of symptoms including skin irritation. Some low cost commercial foods may not supply the appropriate nutrients, even if their advertisements state they provide a full and balanced diet.

Allergies. Just like humans, dogs may become allergic to various substances in their environment. One allergy that many dogs share is an allergy to flea saliva, which makes a flea infestation doubly painful. There is no cure for allergies, only avoidance of the allergen. If your dog is allergic to a common substance, he or she may require allergy shots or antihistamines for comfort.

Infections. Finally, infections are a common cause of itchiness among dogs. The most common types of infection are bacterial and yeast. These infections rarely occur in healthy animals--they usually strike when the dog is tired, stressed, or ill. Bacterial infections of the skin typically look like small bumps. Yeast infections have a greasy appearance and may give off an unpleasant odor. Both types of infection require a vet's intervention.

Unfortunately, man's best friend is often vulnerable to skin problems and itchiness. Dogs may also develop itchiness if they have gotten wet and parts of their fur and skin haven't dried properly. This is known as wet eczema or a "hot spot" and may require a vet's attention for antibiotic or anti-inflammatory drugs.