One of the final types of canine dermatitis is moist. This condition is characterized by the sudden development of raw, moist areas of skin. This type of dermatitis is most common in hot, humid weather. Environmental dermatitis takes time to pinpoint the exact cause because there are so many reasons for the reaction. Immune-mediated Skin Diseases are maladies result from irregular activity of immune system. These diseases are not contagious. Treatment for this disease is rarely successful. It happens to a dog when it is around 2-4 years old.