Is there any medicines to prevent allergic reactions?

Antihistamines are the most common type of medication used to prevent allergic reactions. They work by blocking the effects of histamine, a chemical that is released by the body during an allergic reaction. Antihistamines can be taken orally, as a nasal spray, or as an eye drop.

Mast cell stabilizers are another type of medication that can be used to prevent allergic reactions. They work by preventing the release of histamine from mast cells, which are cells that are involved in the allergic response. Mast cell stabilizers are typically used in conjunction with antihistamines.

Decongestants can be used to relieve nasal congestion that is caused by allergies. They work by narrowing the blood vessels in the nose, which reduces swelling and inflammation. Decongestants are typically used in combination with antihistamines and/or mast cell stabilizers.

Corticosteroids are a type of medication that can be used to treat severe allergic reactions. They work by reducing inflammation and suppressing the immune system. Corticosteroids can be taken orally, as an injection, or as a nasal spray.

Immunotherapy is a type of treatment that can be used to reduce the sensitivity of the immune system to allergens. It involves exposing the person to small amounts of allergens over time, which helps the body to build up immunity to them. Immunotherapy is typically used for people who have severe allergies and who have not responded to other treatments.