Treatment

Interventions for a drug allergy can be divided into two general strategies:

• Treatment for present allergy symptoms
• Treatment that may enable you to take an allergy-causing drug if it's medically necessary

Treating current symptoms

The following interventions may be used to treat an allergic reaction to a drug:

• Withdrawal of the drug. If your doctor determines that you have a drug allergy — or likely allergy — discontinuing the drug is the first step in treatment. In many cases, this may be the only intervention necessary.
• Antihistamines. Your doctor may prescribe an antihistamine or recommend an over-the-counter antihistamine such as diphenhydramine (Benadryl) that can block immune system chemicals activated during an allergic reaction.
• Corticosteroids. Either oral or injected corticosteroids may be used to treat inflammation associated with more-serious reactions.
• Treatment of anaphylaxis. Anaphylaxis requires an immediate epinephrine injection as well as hospital care to maintain blood pressure and support breathing.

Taking allergy-causing drugs

If you have a confirmed drug allergy, your doctor would not prescribe the drug unless it is necessary. In some cases — if the diagnosis of drug allergy is uncertain or there's no alternative treatment — your doctor may use one of two strategies to use the suspect drug.

With either strategy, your doctor provides careful supervision, and supportive care services are available to treat an adverse reaction. These interventions are generally avoided if drugs have caused severe, life-threatening reactions in the past.

Graded challenge

If the diagnosis of a drug allergy is uncertain and your doctor judges that an allergy is unlikely, he or she may recommend a graded drug challenge. With this procedure, you receive two to five doses of the drug, starting with a small dose and increasing to the desired dose.

If you reach the therapeutic dose with no reaction, then your doctor will conclude that you aren't allergic to the drug. You will be able to take the drug as prescribed.

Drug desensitization

If it's necessary for you to take a drug that has caused an allergic reaction, your doctor may recommend a treatment called drug desensitization. With this treatment, you receive a very small dose and then progressively larger doses every 15 to 30 minutes over several hours or days. If you can reach the desired dosage with no reaction, then you can continue the treatment.