Vitamin C is helpful in the treatment of allergies because it lowers the levels of antihistamine in the body. Allergies are not always life threatening such as in acute asthma attacks or anaphylactic shock; they can create annoying, chronic and therefore debilitating symptoms such as stuffy noses, runny noses, headaches and fatigue. Allergies can be identified through blood tests, skin patch tests and exclusion diets. Most allergies can be easily addressed by avoiding the allergens, however some allergens such as seasonal pollens are difficult to avoid. Vitamin C should also be regularly used to limit the impact and occurrence of allergies.