The culprit that causes the allergy is called an allergen. To successfully cure the symptoms of allergy, the irritant allergen must be identified and avoided.
Common allergies come from flea bites, contact with foreign substances, inhalant and food allergies.
For flea bite allergy, the symptoms are hair loss and skin infections. The first step is to eliminate fleas by using flea powders, sprays, shampoos and dips. Follow instructions and avoid excessive exposure to these as chemicals are hazardous to health. Dog products are unique to dogs and can't be used on cats. Inhalant allergies come form inhaling pollen, house dust or mold.