An allergic reaction to penicillin usually results in symptoms that affect the nose, throat, lungs, skin and gastrointestinal tract. These symptoms can be treated with several types of medications, including:

• Antihistamines. Medications that provide relief for hives, sneezing, runny nose and gastrointestinal symptoms. Antihistamines directly counteract the effects of histamines, which are chemicals responsible for most penicillin allergy symptoms. With mild symptoms, these drugs are usually administered orally. For more severe allergic reactions, a physician may recommend an injected form of the drug.
  
  

  

• Bronchodilators. Medications that open the airways of the lung, relieving symptoms such as shortness of breath or wheezing. They may be recommended for people whose penicillin allergies trigger asthma attacks or asthma–like symptoms. They are usually breathed directly into the lungs using an inhaler.
  
  
• Corticosteroids. Medications that reduce inflammation. These medications can be taken regularly to prevent allergic reactions.
  
  
• Epinephrine injection. A synthetic form of adrenaline that, when injected, is a powerful bronchodilator, opening breathing tubes and restoring normal respiration quickly. It is usually reserved for the most severe allergic reactions that involve anaphylactic shock. Most physicians recommend that individuals who are susceptible to severe penicillin reactions carry an injection of epinephrine with them at all times and understand how to self–administer the drug. A medical alert bracelet or necklace is also a good recommendation for these individuals.

Over time, most people who suffer from a penicillin allergy will eventually lose their sensitivity, or have symptoms decrease. However, most physicians recommend that those people who have had an allergic reaction to penicillin avoid the drug for the rest of their lives.

Some people can have their reaction to penicillin reduced through desensitization. This type of treatment involves a person being exposed to small amounts of penicillin every few minutes, gradually weakening the body's sensitivity to the drug for a short period. Typically, this type of treatment only works long enough to give the patient a full dose of penicillin. The next time penicillin is required, the patient must be completely desensitized again. This type of treatment carries some risk, and is generally used only if penicillin is absolutely necessary. Desensitization should only be performed by an experienced physician in a medical facility where the patient can be closely observed.