Common types include allergic dermatitis (from fleas, food, or environment), contact dermatitis (from chemicals or plants), and bacterial or yeast dermatitis (often secondary to another condition). Symptoms vary but typically involve scratching, licking, redness, hot spots, or thickened skin. Diagnosis starts with a physical exam, skin scraping, and sometimes allergy testing or elimination diets. Treatment addresses the underlying cause: parasite control for flea allergy, dietary changes for food sensitivity, medicated baths for infections, and anti-itch medications for comfort. Chronic dermatitis may require long-term management plans combining multiple approaches.