What can cause itchiness and dandruff formation on the back of a dog?

Several conditions can result in scaly and itchy skin. The most common causes in the dog are dry and irritated skin, or an ectoparasite infection, such as a mite infestation (Cheyletiella). If you suspect a parasite infection you should book an appointment with a veterinarian. If the dog only seems to suffer from dry skin you can try using a mild dog shampoo and conditioner (purchased at your local veterinary clinic or pet store) to see if it alleviates the condition.