There's nothing worse than an itch, is there? It's bad enough for humans, but imagine what it must be like for a dog, with all that hair, and all those inaccessible places where itches can strike. If we can't reach an itch, we can ask someone to rub or scratch the affected area, but your dog can't do that. There are many causes of itchy skin in dogs, but these are probably the most common.
A dog's coat is the equivalent of 5 star hotel accommodation to fleas, mites and other parasites. Fleas are easy to spot, but some parasites are so small that they are invisible to the naked eye. If your dog is scratching like mad and you can't see anything that could be causing it, perhaps he has a parasite infestation. Mange, which is also caused by a parasite, is unsightly and can cause itchy skin. Your vet will know the signs and symptoms to look for.
Dogs have allergies too, although it may be difficult to pinpoint the cause of Fido's allergic reaction. Think about it. Have you used any new products such as dog shampoos, or have you tried any new floor or carpet cleaning products in the home? Your dog may have reacted badly to one of the ingredients. If your dog developes itchy skin after the introduction of a new brand of food, he could have an intolerance to one of the ingredients in it. Or he may be allergic to grass or pollen, so think about where you've exercised him as well.
Trial and error should get to the root of the problem eventually, and antihistamines will alleviate the symptoms, while you do the detective work to identify your dog's allergy.
Fungal and other infections
Yeast infections and ringworm can cause itchy skin, and, if untreated, can be passed to other animals and members of the family. There will be local soreness and infection, so this should be relatively easy to detect, diagnose and treat. Hot spots can also cause itchy skin, as can ear infections. If your dog shakes his head a lot, and there is a disharge or bad smell in the area around his ears, this could be the problem.
If your dog is anxious about anything or bored, it may manifest in itchy skin. Don't leave him alone for long periods of time, and try to keep him occupied, so he doesn't worry away at dry skin spots.
Itchy skin may not indicate serious health problems in your dog, but it's uncomfortable and irritating for him, and it may cause changes in his behaviour or depression if left untreated, so don't dismiss it as unimportant. Investigate the causes and treat the symptoms as soon as possible to ensure the problem does not accelerate to a stage where it is a threat to your dog's wellbeing.