Apart from parasites are there any other causes of skin disease in dogs?

itching or pruitus is an obvious sign of skin disease, and although frequently caused by parasites, itching occurs whenever the skin is damaged or inflamed. Itching is one of the major signs of allergic skin diseases. Important allergies in dogs are due to inhalation of pollens, moulds or house dust, insect bites and stings and direct skin contact with chemicals in soaps and detergents, carpets, flea collars, plastics etc. Although foodstuffs are often blamed they are rarely responsible. Bacterial infections can cause skin diseases. Hormonal disorders can cause loss of hair, which is identical on both sides of the body, occurring without any skin irritation. Skin can also be involved in the growth of tumors and at times is affected by very bizarre conditions such as cutaneous asthenia in which the skin can be stretched to extremes but also tears very easily and canine icthyosis where much of the body surface is covered with grey scales and feather-like projections.