There are several possible reasons why your pet is excessively itching. Common reasons may include:
Bacterial or fungal infections: Bacterial or fungal infections are a common cause of pruritus.
Atopic dermatitis: Also called allergic dermatitis, this is often caused by an allergen from the environment, such as from pollen, and plants, so it can be seasonal.
Flea allergy dermatitis: This is a type of allergy that occurs when fleas inject saliva into a pet's body. The proteins within the saliva trigger the immune system, causing itching that typically lasts several days.
Food allergies: Food allergies are often seen in pets with year-round itching.