Corticosteroids are a group of anti–inflammatory drugs similar to hormones produced by the body. They are used to treat a variety of allergic conditions, including asthma, hay fever and eczema. They work by reducing inflammation in the airways, opening the breathing tubes and allowing normal respiration.

Corticosteroids can be taken in several forms, with each of the different forms used to treat different conditions.

These forms include:

• Inhaled methods. Used long–term to preventatively treat allergies and asthma.
  
  
• Nasal sprays. Used to treat inflammation in the nose and sinuses.
  
  
• Topical creams. Used to treat inflammation of the skin (e.g., eczema, rash).
  
  
• Oral methods (e.g., pills, liquids). Used to quickly treat allergy and asthma episodes (e.g., allergic reaction, asthma attack).
  
  
• Intravenous methods. Used to quickly treat allergy and asthma episodes, and usually administered by a physician.

Most corticosteroids are available only with a physician’s prescription. However, some topical creams are available over–the–counter.

Corticosteroids can have a wide range of serious side effects – particularly when oral forms of the drugs are taken for long periods of time. Inhaled corticosteroids are more localized and do not cause as many side effects. Many types of other medications can interfere with corticosteroids, and the medication should be used only after talking with a physician.